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A PHY/MAC Proposal for IEEE WRAN Systems

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1 A PHY/MAC Proposal for IEEE 802.22 WRAN Systems
Month Year doc.: IEEE yy/xxxxr0 March 2006 A PHY/MAC Proposal for IEEE WRAN Systems IEEE P Wireless RANs Date: Authors: Name Company Address Phone John Benko France Telecom (FT) USA Yoon Chae Cheong SAIT Korea Carlos Cordeiro Philips Wen Gao Thomson Inc. Chang-Joo Kim ETRI Hak-Sun Kim Samsung Electro-mechanics Stephen Kuffner Motorola Joy Laskar Georgia Institute of Technology Ying-Chang Liang Institute for Infocomm Research Singapore Notice: This document has been prepared to assist IEEE It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard." Early disclosure to the Working Group of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chair Carl R. Stevenson as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE Working Group. If you have questions, contact the IEEE Patent Committee Administrator at > ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

2 Georgia Institute of Technology
Month Year doc.: IEEE yy/xxxxr0 March 2006 Co-Authors Name Company Address Phone Myung-Sun Song ETRI Korea Soon-Ik Jeon Gwang-Zeen Ko Sung-Hyun Hwang Bub-Joo Kang Chung Gu Kang KyungHi Chang Yun Hee Kim Moon Ho Lee HyungRae Park Martial Bellec France Telecom France Denis Callonnec Luis Escobar Francois Marx Patrick Pirat Kyutae Lim Georgia Institute of Technology USA Youngsik Hur ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

3 Co-Authors March 2006 Month Year doc.: IEEE 802.22-yy/xxxxr0 Name
Company Address Phone Wing Seng Leon I2R Singapore Yonghong Zeng Changlong Xu Ashok Kumar Marath Anh Tuan Hoang Francois Chin Zhongding Lei Peng-Yong Kong Chee Wei Ang Yufei Blankenship Motorola USA Brian Classon Fred Vook Jeff Zhuang Kevin Baum Tim Thomas David Grandblaise France ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

4 Samsung Electro-Mechanics Samsung Electronics Co. Ltd.
March 2006 Co-Authors Name Company Address Phone Dagnachew Birru Philips USA Kiran Challapali Vasanth Gaddam Monisha Ghosh Gene Turkenich Duckdong Hwang SAIT Korea Chung Jaehak Kim Jaemyeong Ashish Pandharipande Yoo Sangjo Jeong Suk Lee Samsung Electro-Mechanics Chang Ho Lee Wangmyong Woo David Mazzarese Samsung Electronics Co. Ltd. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

5 Samsung Telecom America
March 2006 Co-Authors Name Company Address Phone Baowei Ji Samsung Telecom America USA Max Muterspaugh Thomson Inc. Hang Liu Paul Knutson Josh Koslov ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

6 Presentation Outline PHY Proposal Updates to the MAC Proposal
March 2006 Presentation Outline PHY Proposal Updates to the MAC Proposal Conclusions ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

7 Presentation Outline PHY Proposal Updates to the MAC Proposal
March 2006 Presentation Outline PHY Proposal Updates to the MAC Proposal Conclusions ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

8 March 2006 Disclaimer The following set of slides represent the joint ETRI-France Telecom-I2R-Motorola-Philips-Samsung-Thomson PHY proposal This is in contrast to the MAC presentation, which is confined to describe only the updates ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

9 PHY Outline Overview/ Channel bonding Fractional Bandwidth
March 2006 PHY Outline Overview/ Channel bonding Fractional Bandwidth Sub-Channelization, pilot insertion Error Correction Coding Multiple antenna Sensing ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

10 PHY Overview OFDMA both in uplink and downlink
March 2006 PHY Overview OFDMA both in uplink and downlink QPSK, 16-QAM, and 64-QAM, transformed-QPSK More than 30 sub channels per TV channel Contiguous channel bonding upto 3 TV channels (and beyond in a stack manner) Data rate range from 5Mbps to 70Mbps TDD, FDD ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

11 What We Have Proposed …. Adaptive OFDMA Known and proven technology
March 2006 What We Have Proposed …. Adaptive OFDMA Known and proven technology for broadband fixed/mobile wireless access (e.g., IEEE d/e – WiBro in Korea) Adaptively scalable to spectrum availability Channel Bonding New frame structure for CR-enabled operation Enhanced PHY features - Adaptive sub-carrier allocation - Adaptive pilot insertion - Enhanced channel coding (LDPC, Turbo Code, SBTC) - Multiple antenna options ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

12 Advantages of Adaptive OFDMA Proposal
Month Year doc.: IEEE yy/xxxxr0 March 2006 Advantages of Adaptive OFDMA Proposal Flexible Bandwidth Allocation To use the partial bandwidth (1, 2, 3, 4, 5, 6, 7, 8 MHz) adaptively, depending on the channel state information (availability) To fully utilize available bandwidth under a unified PHY framework Single Sampling Frequency Sampling frequency is the same for all FFT modes. Constant Subcarrier Spacing The subcarrier spacing is constant for all different channel bandwidths  Robust to the frequency offset ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

13 PHY (Baseband) Architecture
Month Year doc.: IEEE yy/xxxxr0 March 2006 PHY (Baseband) Architecture ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

14 System Parameters: Proposed
Month Year doc.: IEEE yy/xxxxr0 March 2006 System Parameters: Proposed Parameters Specification Remark Frequency range 54~862 MHz Service coverage Typical range 33 km, Bandwidth Mandatory: 6, 7, 8 MHz with channel bonding Optional: fraction BW Allows the fractional use of TV channel and channel bonding up to 3 TV channels Data rate Maximum: 70 Mbps Minimum: 4.5 Mbps Maximum of 23 Mbps for 6 MHz Spectral Efficiency Maximum: 3.94 bits/s/Hz Minimum: 0.75 bits/s/Hz Single TV channel BW of 6 MHz Modulation QPSK, 16QAM, 64QAM Transmit power Default 4W EIRP Multiple Access Adaptive OFDMA Partial bandwidth allocation FFT Mode 1024, 2048, 4096, 6144 Cyclic Prefix Mode 1/4, 1/8, 1/16, 1/32 Duplex TDD or FDD Network topology Point-to-Multipoint Network ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

15 Channel Bonding: Motivation
March 2006 Channel Bonding: Motivation Spectrum occupancy measurements conducted by Shared Spectrum Company from January/2004 to August/2005 have shown that: “There is a significant amount of spectrum available in continuous blocks that are 1 MHz and wider ” “A dynamic spectrum sharing radio with a low agility, contiguous waveform will provide high utility” The November 18, 2005, study from Freepress and New America Foundation (entitled “Measuring the TV “White Space” Available for Unlicensed Use”) reveals that there exists a considerable amount of contiguous vacant TV channels (especially in the upper UHF band) More can be expected in other countries ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

16 Contiguous open spectrum available!
March 2006 Contiguous open spectrum available! Example: Jackson, Mississippi Source: “Measuring the TV ‘White Space’ Available for Unlicensed Wireless Broadband”, Nov 18, 2005, New America Foundation ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

17 March 2006 Channel Bonding Make opportunistic and simultaneous use of multiple contiguous TV channels Benefits: More data rate or range Initial link-budget analysis showed that single-TV channel can not support full data rate (e.g., 18Mbps) upto 30 Km range Multi-path Diversity Small BW signal can have deep fade or flat fade Wider-bandwidth signal provides more frequency/multipath diversity Interference Wider-band reduces the amount of interference ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

18 Channel Bonding: Capacity
March 2006 Channel Bonding: Capacity Aggregate TV channels to get more capacity Shannon: C = B.log2(1+S/N) capacity proportional to BW, but logarithmic with SNR or signal power If S/N is fixed, then capacity increases linearly with bandwidth If signal power is fixed, but bandwidth is increased C = B.log2(1+S/(BNo)) Capacity still increases as bandwidth is increased ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

19 March 2006 Capacity of aggregated channels as a given signal power is spread over more channels ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

20 Preliminary Link Budget (LOS)
March 2006 Preliminary Link Budget (LOS) Difficult to achieve 19Mbps over 30Km channel bonding needed to achieve long range ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

21 Channel Bonding Scheme
March 2006 Channel Bonding Scheme 6, 12, 18 MHz channels Constant inter-carrier spacing Depends on availability Several receiver techniques to deal with flexible BW Selectable analog filters Up sampling digital filters ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

22 Channel bonding structure
March 2006 Channel bonding structure 6K FFT over 3 TV channels 2K per TV channel Null out the outer carriers for 1 or 2 TV channels Fixed inter-carrier spacing Several implementation possibilities 6 MHz 12 MHz 18 MHz ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

23 FFT Mode for WRAN Systems
Month Year doc.: IEEE yy/xxxxr0 March 2006 FFT Mode for WRAN Systems No. of Bonded Channel Basic FFT Mode 1 2 3 1K 2K NA 4K 6K ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

24 Superframe Structure March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

25 Preamble Superframe preamble Frame preamble: 1-3 TV channels
March 2006 Preamble Superframe preamble Over 1512 sub-carriers (every fourth or second non-zero), 5 MHz BW Simply duplicate for additional TV channels 1 MHz gap between adjacent channels to relax filtering 2 symbol duration (1 more for data) Frame preamble: 1-3 TV channels 1728*N sub-carriers Short preamble is optional Example structure (short) (long) ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

26 Preamble Preamble has the repetition pattern in the time domain:
Month Year doc.: IEEE yy/xxxxr0 March 2006 Preamble Preamble has the repetition pattern in the time domain: Time synchronization Frequency synchronization Channel estimation Cell ID detection Preamble is modulated using BPSK modulation. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

27 Transformed QPSK/OFDMA
March 2006 Transformed QPSK/OFDMA Spread data over some sub-carriers (QPSK only) Hadamard Two-carrier FFT based unitary pre-coding Frequency offset DFT Depending on the receiver structure, this can Increase capturing of multipath diversity Increase resiliency to interferers Receiver structures MMSE Approximate ML ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

28 OFDMA Parameters/Single Channel (6MHz)
Month Year doc.: IEEE yy/xxxxr0 March 2006 OFDMA Parameters/Single Channel (6MHz) Mode 1K 2K 4K 6K FFT Size 1024 2048 4096 6144 Bandwidth (k = 1, 2, …, 6) k MHz Sampling Factor 8/7 No. of Used Subcarriers (including pilot, but not DC) 140 * k 280 * k 560 * k 840 * k Sampling Frequency 48/7 MHz Subcarrier Spacing 6.696 kHz(***) 3.348 kHz 1.674 kHz 1.116 kHz Occupied Bandwidth 6.696 kHz*140*k 3.348 kHz*280*k 1.674 kHz*560*k 1.116 kHz*840*k Bandwidth Efficiency(*) 93~94 % FFT Time us us us 896 us Cyclic Prefix Time(**) 37.33 us 74.66 us 224 us OFDMA Symbol Time us us us 1120 us (*) Bandwidth Efficiency = Subcarrier Spacing * (Number of Used Subcarriers + 1)/BW (**) It is assumed that cyclic prefix mode is 1/4. (***) Italics indicate an approximated value. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

29 OFDMA Parameters/Single Channel (7MHz)
Month Year doc.: IEEE yy/xxxxr0 March 2006 OFDMA Parameters/Single Channel (7MHz) Mode 1K 2K 4K 6K FFT Size 1024 2048 4096 6144 Bandwidth (k = 1, 2, …, 7) k MHz Sampling Factor 8/7 No. of Used Subcarriers (including pilot, but not DC) 120 * k 240 * k 480 * k 720 * k Sampling Frequency 8 MHz Subcarrier Spacing 7.812 kHz(***) 3.906 kHz 1.953 kHz 1.302 kHz Occupied Bandwidth 7.812 kHz*120*k 3.906 kHz*240*k 1.953 kHz*480*k 1.302 kHz*720*k Bandwidth Efficiency(*) 93~94 % FFT Time 128 us 256 us 512 us 768 us Cyclic Prefix Time(**) 32 us 64 us 192 us OFDMA Symbol Time 160 us 320 us 640 us 960 us (*) Bandwidth Efficiency = Subcarrier Spacing * (Number of Used Subcarriers + 1)/BW (**) It is assumed that cyclic prefix mode is 1/4. (***) Italics indicate an approximated value. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

30 OFDMA Parameters/Single Channel (8MHz)
Month Year doc.: IEEE yy/xxxxr0 March 2006 OFDMA Parameters/Single Channel (8MHz) Mode 1K 2K 4K 6K FFT Size 1024 2048 4096 6144 Bandwidth (k = 1, 2, …, 8) k MHz Sampling Factor 8/7 No. of Used Subcarriers (including pilot, but not DC) 105 * k 210 * k 420 * k 630 * k Sampling Frequency 64/7 MHz Subcarrier Spacing 8.928 kHz(***) 4.464 kHz 2.232 kHz 1.488 kHz Occupied Bandwidth 8.928 kHz*105*k 4.464 kHz*210*k 2.232 kHz*420*k 1.488 kHz*630*k Bandwidth Efficiency(*) 93~94 % FFT Time 112 us 224 us 448 us 672 us Cyclic Prefix Time(**) 28 us 56 us 168 us OFDMA Symbol Time 140 us 280 us 560 us 840 us (*) Bandwidth Efficiency = Subcarrier Spacing * (Number of Used Subcarriers + 1)/BW (**) It is assumed that cyclic prefix mode is 1/4. (***) Italics indicate an approximated value. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

31 OFDMA parameters – channel bonding
March 2006 OFDMA parameters – channel bonding Parameter 3 TV bands 2 TV bands 1 TV bands 18 21 24 12 14 16 6 7 8 Inter-carrier spacing, DF (Hz) 3348 3906 4464 FFT period, TFFT (ms) 298.66 256.00 224.00 Total no. of sub-carriers, NFFT 6144 4096 2048 No. of guard sub-carriers, NG (L, DC, R) 1104 (552,1,551) 736 (368,1,367) 368 (184,1,183) No. of used sub-carriers, NT = ND + NP 5040 3360 1680 No. of data sub-carriers, ND 4680 3120 1560 No. of pilot sub-carriers, NP 360 240 120 Occupied bandwidth (MHz) 16.884 19.698 22.512 11.256 13.132 15.008 5.628 6.566 7.504 Bandwidth Efficiency (%) 93.8 ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

32 Data Rate Bandwidth = 6 MHz FFT size = 2048 Cyclic prefix mode = 1/4
March 2006 Data Rate Bandwidth = 6 MHz FFT size = 2048 Cyclic prefix mode = 1/4 No pilot, no quiet periods assumed Unit: Mbps Code Rate Modulation 7/8 5/6 3/4 2/3 1/2 64QAM 23.63 22.50 20.25 18.00 13.50 16QAM 15.75 15.00 12.00 9.00 QPSK 7.88 7.50 6.75 6.00 4.50 Data Rate = No. of used subcarriers * code rate * no. of bits per modulation symbol/OFDM symbol time ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

33 Data Rate – Channel Bonding
March 2006 Data Rate – Channel Bonding Bandwidth = 3*6 MHz FFT size = 2048 Cyclic prefix mode = 1/4 No pilot, no quiet periods assumed Unit: Mbps Code Rate Modulation 7/8 5/6 3/4 2/3 1/2 64QAM 70.89 67.50 60.75 54.00 40.50 16QAM 47.25 45.00 36.00 27.00 QPSK 23.64 22.50 20.25 18.00 13.50 Data Rate = No. of used subcarriers * code rate * no. of bits per modulation symbol/OFDM symbol time * no. of channel bonded ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

34 Spectral Efficiency Single channel bandwidth = 6 MHz FFT size = 2048
Month Year doc.: IEEE yy/xxxxr0 March 2006 Spectral Efficiency Single channel bandwidth = 6 MHz FFT size = 2048 Cyclic prefix mode = 1/4 No pilot, no quiet periods assumed The spectral efficiency is same for all fractional BW mode Unit : bps/Hz Code Rate Modulation 7/8 5/6 3/4 2/3 1/2 64QAM 3.94 3.75 3.38 3.00 2.25 16QAM 2.63 2.50 2.00 1.50 QPSK 1.31 1.25 1.13 1.00 0.75 Spectral Efficiency = No. of used subcarrier*code rate*no. of bits per modulation symbol/OFDM symbol time/BW ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

35 Minimum Peak Throughput per CPE
Month Year doc.: IEEE yy/xxxxr0 March 2006 Minimum Peak Throughput per CPE Bandwidth = 6 MHz FFT size = 2048 Cyclic prefix mode = 1/4 No. of CPE’s = 512 CPE’s/oversubscription ratio 50 ~ 11 CPE’s No pilot, no quiet periods assumed Unit : Mbps Code Rate Modulation 7/8 5/6 3/4 2/3 1/2 64QAM 2.15 2.05 1.84 1.64 1.23 16QAM 1.43 1.36 1.09 0.82 QPSK 0.72 0.68 0.61 0.55 0.41 Min. Peak Throughput = No. of used subcarriers*code rate*no. of bits per modulation symbol/OFDM symbol time/no. of CPE’s ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

36 Fractional BW Usage March 2006 Month Year doc.: IEEE 802.22-yy/xxxxr0
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

37 Fractional Bandwidth Usage
Month Year doc.: IEEE yy/xxxxr0 March 2006 Fractional Bandwidth Usage If wireless microphones are in operation in TV channel, the WRAN systems may be clear the entire TV channel The number of used sub-carriers is proportional to the fractional bandwidth The fractional BW mode is identified by using a Preamble Example: ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

38 Fractional Bandwidth Mode
Month Year doc.: IEEE yy/xxxxr0 March 2006 Fractional Bandwidth Mode Total Number of Fractional BW Mode To Detect : 36 Start position of fractional BW mode 1 2 3 4 5 6 7 8 Null 1 2 3 4 5 6 7 8 Fractional BW mode zone Fractional BW of 1 MHz Fractional BW Real BW of 8 MHz Not applicable Null Start position of fractional BW mode ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

39 Preamble Sequence for Fractional BW Usage (2K FFT)
Month Year doc.: IEEE yy/xxxxr0 March 2006 Preamble Sequence for Fractional BW Usage (2K FFT) Index Fractional BW Start Position PN Sequence (1680 bits) 1 0x251D994101EDA04D8BD0B8EA6FA20AE590C2CC199AB083C6AE61F091F2DD41D989EC164B1481D611BE9CEA0094AFE9DB56A4763F55B26E54EAB73ACD7D4BBA64C1421BC3EB9D67113A5FB9C529AADC9CAB1FB CDB69AFCBADDF8B42314A7985B5F87C D350454FF FADAE4711DD0CC5DACEDF7CD5DF1177D60EBA4DBE657F19F08189EFC6B5DE6C2CFDCD13195DE077586B8EE01E00B6468B10A53FAAC1DD846E2A D444B6AD0D34C34EC9CFD EC9FBAE498F5A20614BDF3E4B22D 2 3 4 5 6 7 8 9 10 11 12 13 14 33 34 35 This sequence will be determined to minimize the PAPR ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

40 Flow Diagram of Fractional BW Mode Detection
Month Year doc.: IEEE yy/xxxxr0 March 2006 Flow Diagram of Fractional BW Mode Detection CPE Power On Fractional BW Mode Detection Using Preamble Fractional BW Usage Mode Signal Detection & Automatic Gain Control Decoding Superframe Control Header (SCH) Channel Bonding Information Superframe Preamble Start Position Detection Decoding Frame Synchronization & Channel Estimation ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

41 Simple Mode Detection Procedure (1)
Month Year doc.: IEEE yy/xxxxr0 March 2006 Simple Mode Detection Procedure (1) Search the Fractional BW Usage Mode (Correlation with All Preamble Sequence) CPE Power On CorrelationOut>TH ? NO YES Confirm the Fractional BW Usage Mode (Correlation with Previous Preamble Sequence) ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

42 Simple Mode Detection Procedure (2)
Month Year doc.: IEEE yy/xxxxr0 March 2006 Simple Mode Detection Procedure (2) Example: Transmitted SuperPreamble Index … … … … Fractional mode changed Correlated SuperPreamble Index All 0 … … … … The Correlation Out is less than the Threshold Detected SuperPreamble Index … … … … Search all fractional mode again ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

43 Subchannelization March 2006 Month Year doc.: IEEE 802.22-yy/xxxxr0
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

44 Symbol Structure For AMC/Diversity Subchannel
Month Year doc.: IEEE yy/xxxxr0 March 2006 Symbol Structure For AMC/Diversity Subchannel The concept of AMC subchannel is same to that of The concept Diversity subchannel is same to the DL optional FUSC of Just the number of used subcarriers is different 802.16e: no. of subchanel=32, no. of subcarriers per subchannel=54 802.22: no. of subchanel=30, no. of subcarriers per subchannel=56 So the basic permutation sequence will be slightly modified ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

45 Pilot Pattern Design (1)
Month Year doc.: IEEE yy/xxxxr0 March 2006 Pilot Pattern Design (1) Pilot pattern is varied with channel condition Pilot pattern is controlled by adjusting the pilot symbol interval and pilot subcarrier interval A robust channel parameter estimation is required for reliable pilot design ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

46 Pilot Pattern Design (2)
Month Year doc.: IEEE yy/xxxxr0 March 2006 Pilot Pattern Design (2) RMS delay spread of WRAN profile (Approximated) Pilot subcarrier interval can be determined as follows Pilot subcarrier interval*subcarrier spacing < coherent bandwidth Multipath Profile A B C D RMS Delay Spread 692 ns 847 ns 1073 ns 5917 ns (*) (*) We assume that the 6-th path has the excess delay of 60 ns and relative amplitude of -10 dB Multipath Profile Parameters A B C D Coherent Bandwidth (kHz) 90% 28.90 23.61 18.63 3.38 50% 289.02 236.13 186.39 33.80 Pilot Subcarrier Interval 8.63 7.05 5.56 1.00 86.32 70.52 55.67 10.09 1) We assume that the BW is 6 MHz and FFT mode is 2K. 2) 90% coherent BW=1/(50*rms delay spread), 50% coherent BW=1/(5*rms delay spread) ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

47 Pilot Pattern Design (3)
Month Year doc.: IEEE yy/xxxxr0 March 2006 Pilot Pattern Design (3) Coherent Time 1/fm, where, fm is the maximum doppler shift Pilot symbol interval can be determined as follows Pilot symbol interval*OFDMA symbol time < coherent time Multipath Profile Parameters A B C D Maximum Doppler Shift (Hz) 2.5 Coherent Time (sec) 0.4 Pilot Symbol Interval 1071.4 Here, we assume that the BW is 6 MHz, FFT mode is 2K, and GI mode is 1/4. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

48 Pilot Pattern For AMC Subchannel
Month Year doc.: IEEE yy/xxxxr0 March 2006 Pilot Pattern For AMC Subchannel Typical BIN structure Set of 14 contiguous subcarriers within an OFDMA symbol AMC subchannel consists of 4 contiguous bins 12 Data Subcarriers 2 Pilot Subcarriers ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

49 Pilot Pattern For Diversity Subchannel
Month Year doc.: IEEE yy/xxxxr0 March 2006 Pilot Pattern For Diversity Subchannel All the pilot subcarriers are allocated first And then the remaining subcarriers are used exclusively for data transmission Number of used subcarriers are divided into 14 contiguous subcarriers in which two pilot subcarriers are allocated The position of the pilot subcarriers in 14 contiguous subcarriers varies according to the index of OFDMA symbol which contains the subcarriers Pilot subcarrier index: k : pilot subcarrier index, 0,…,239 for 2K mode m : [symbol index] mod 3 ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

50 Advanced Channel Coding
Month Year doc.: IEEE yy/xxxxr0 March 2006 Advanced Channel Coding ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

51 Channel Coding Coding Scheme Selected Code Rates
Month Year doc.: IEEE yy/xxxxr0 March 2006 Channel Coding Coding Scheme Mandatory: Convolutional Code -> similar to Optional: Duo Binary Turbo Code LDPC Code (IEEE e LDPC) New Shortened block turbo code New Optional advanced codes currently undergoing cross-simulations Will compare results and select best optional code(s) Selected Code Rates R = 1/2, 2/3, 3/4, 5/6 ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

52 Duo-Binary Turbo-Code Summary
Month Year doc.: IEEE yy/xxxxr0 March 2006 Duo-Binary Turbo-Code Summary Excellent performance for wide range of blocks Have optimized parameters for blocks from 6 bytes to 240 bytes Highly flexible scheme Same encoder/decoder for all blocksizes/coding rates Reasonable complexity ~35% decrease in complexity/decoded bit compared to Binary TC. Mature Technology Code Reuse/ Already in following standards IEEE / WiMAX; HomePlug, DVB-RCS, DVB-RCT, ETSI HIPERMAN ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

53 Low-Density Parity-Check Codes
Month Year doc.: IEEE yy/xxxxr0 March 2006 Low-Density Parity-Check Codes Motivation for LDPC Near capacity performance High-throughput low-complexity implementation Code reuse between 802 specifications Features of IEEE e LDPC codes Compact representation of code matrices Simplified structured encoder/decoder architecture across all code rates Low-complexity differential-style encoding Enhanced Layered Decoding to reduce the number of iterations Special design feature in rate 1/2, 2/3 code provides further throughput doubling in layered decoding ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

54 Month Year doc.: IEEE yy/xxxxr0 March 2006 LDPC Code Reuse Within 802 LDPC codes adopted in DVB-S2, e, n IEEE Initial WiMax profile includes CC and CTC, Chase Combining HARQ for CTC Future WiMAX profiles likely to include… CTC with incremental redundancy (IR) HARQ IR may add little value for fixed access LDPC with Chase Combining Missed first profile due to time-to-market considerations IEEE n IEEE e-style LDPC codec adopted as the only advanced channel coding scheme in January 2006 joint proposal Selecting LDPC for would lead to additional reuse to/from indoor antenna radio 802.11n radio Common baseband elements to/from rooftop antenna ethernet ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

55 Shortened Block Turbo Code (SBTC)
March 2006 Shortened Block Turbo Code (SBTC) Turbo product code (TPC) is an advanced coding option in STBC is an improved form of TPC SBTC has lower decoding complexity than TPC without performance loss Component code Extended Hamming code Native code: (16,11), (32,26) and (64,57) Other code rate through shortening Parity check code (8,7) and (16,15) ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

56 Parity Check Matrices for Hamming Codes
Month Year doc.: IEEE yy/xxxxr0 March 2006 Parity Check Matrices for Hamming Codes N’ = 15 K’ = 11 N’ = 31 K’ = 26 N’ = 63 K’ = 57 Special parity check matrix design simplifies the decoding complexity. The syndrome value gives the error position, thus, look-up table is not needed. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

57 Multiple Antennae Options
Month Year doc.: IEEE yy/xxxxr0 March 2006 Multiple Antennae Options ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

58 Multiple Antenna Options
Month Year doc.: IEEE yy/xxxxr0 March 2006 Multiple Antenna Options Multiple antennae techniques offer various advantages in various scenarios, including inherent benefits for the protection of incumbents. We are studying the following options. Final decisions on which ones are included will be based on performance and complexity. Equal Gain Transmit Beamforming Using Codebooks. Downlink Closed Loop SDMA. Adaptive Beam-Forming Techniques. Space Time Block Coding (STBC). Combined Diversity/Spatial multiplexing/Delay Management. Uplink “Virtual” SDMA MIMO. 그럼 이번 연구의 내용인 HPi system을 위한 적응 빔 형성 알고리즘에 대하여 설명하겠습니다. 이 그림은 HPi systme의 상향 링크용 스마트 안테나 알고리즘으로서 이는 High-resolution DOA algorithm에 기반을 두었습니다. 그래서 먼저 원하는 신호와 간섭 신호의 도래각을 추정한 후 원하는 신호의 방향으로는 main beam을 형성하고 간섭 신호의 방향으로는 null을 형성하는 알고리즘 입니다. 먼저 배열 안테나를 이용하여 신호를 수신한후, FFT를 취합니다. 그리고 원하는 신호의 주파수 bin을 추출신호가 있는 주파수를 선택하여 covariance matrix를 추정합니다. Covariance matrix에 대하여 eigen-decomposition 과정을 거친후 DOA를 추정합니다. 추정된 DOA를 통하여 간섭과 잡음의 covariance matrix를 생성 합니다. 그후, 생성된 covariance matrix를 이용하여 beam-forming weight vector를 계산합니다. 그리고 계산된 weight vector를 이용하여 beam pattern을 형성합니다. 이 알고리즘에 대하여 약간 구체적으로 살펴보겠습니다. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

59 Equal Gain Transmit Beamforming
March 2006 Equal Gain Transmit Beamforming When multiple antennae are used for transmission, it is very important to have equal gain transmissions from each antenna, especially when used with OFDM. Eigen-beamforming, when used in an asymmetrical situation (NT > NR), DOES NOT guarantee equal power. Single-stream or multiple stream transmission is proposed ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

60 Quantized Equal Gain Beamformer For Single Stream
March 2006 Quantized Equal Gain Beamformer For Single Stream NT transmit antennae and NR receive antennae (NR could be 1). Objective: find quantized beamformer Q (NT X 1). Method: All entries of Q are restricted to be First entry is fixed at 1+ j Q is picked to maximize No. of bits required to specify Q: 2*(NT -1) per frequency bin. If p consecutive frequencies are grouped, Q is picked to maximize e.g: 2x1 beamformer, grouping 4 tones over 64 tones bandwidth would require only 4 bytes of feedback, with ~ 1dB degradation. Multiple streams: find multiple beamformers of that form for the simultaneous transmission of multiple streams to 1 user ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

61 Quantized Equal Gain Beamformer Performance Summary
March 2006 Quantized Equal Gain Beamformer Performance Summary Performance summary was presented in January 2006 [doc.: IEEE /0005r1] Very simple and efficient codebook based beamforming, ensuring equal gain transmissions. About 6 –7dB downlink gain with 2 transmit antennae. About 11-12dB downlink gain with 4 transmit antennae. Similar gains on uplink, with receive-diversity at base-station. Gains can be realized with about 4 bytes of feedback per user for 2 transmit antennae and 12 bytes per user for 4 transmit antennae. CPE could have more receive antenna than transmit antennae, for added performance, without changing the feedback requirements. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

62 March 2006 Downlink Closed-Loop SDMA (CL-SDMA) Linear processing with downlink channel sounding Throughput performance was presented in January 2006 [doc.: IEEE /0016r1] Very large throughput can be achieved by the use of reliable channel state information at the transmitter in slowly fading channels, to allow for coordinated beamforming between the transmitter and the receivers Practical implementation: In FDD or TDD: CL-SDMA Mode 1 (2 base station antennas) No channel reciprocity requirement: finite-rate quantized feeedback In TDD: CL-SDMA Mode 2 (2 or more base station antennas) Requires channel reciprocity: direct uplink sounding Use on adjacent permutation subcarriers with multiuser diversity ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

63 March 2006 CL SDMA Overview The Base Station has N transmit antennas, and uses N beamforming vectors M1 … MN CPEs have N or more receive antennas, and use beamforming vectors W1 , W2 … WN CL SDMA Mode 1 is only applicable with N = 2 transmit antennas. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

64 Base Station Transmitter and CPE Receiver Structures
March 2006 Base Station Transmitter and CPE Receiver Structures Receiver or user k ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

65 Adaptive Beam-Forming
Month Year doc.: IEEE yy/xxxxr0 March 2006 Adaptive Beam-Forming Adaptive beam-forming (ABF) for systems: Mitigate co-channel interference (CCI) inherent to OFDMA systems Since all CPEs are fixed at known locations, their directions-of- arrival (DOAs) may easily be obtained at the BS. Large cell in networks also makes beam-forming problem simple from 2D to 1D problem: easy DOA estimation. With the transmit and/or receive diversity, adaptive beam-forming may significantly increase the cell radius. More efficient than fixed-beam array 그럼 이번 연구의 내용인 HPi system을 위한 적응 빔 형성 알고리즘에 대하여 설명하겠습니다. 이 그림은 HPi systme의 상향 링크용 스마트 안테나 알고리즘으로서 이는 High-resolution DOA algorithm에 기반을 두었습니다. 그래서 먼저 원하는 신호와 간섭 신호의 도래각을 추정한 후 원하는 신호의 방향으로는 main beam을 형성하고 간섭 신호의 방향으로는 null을 형성하는 알고리즘 입니다. 먼저 배열 안테나를 이용하여 신호를 수신한후, FFT를 취합니다. 그리고 원하는 신호의 주파수 bin을 추출신호가 있는 주파수를 선택하여 covariance matrix를 추정합니다. Covariance matrix에 대하여 eigen-decomposition 과정을 거친후 DOA를 추정합니다. 추정된 DOA를 통하여 간섭과 잡음의 covariance matrix를 생성 합니다. 그후, 생성된 covariance matrix를 이용하여 beam-forming weight vector를 계산합니다. 그리고 계산된 weight vector를 이용하여 beam pattern을 형성합니다. 이 알고리즘에 대하여 약간 구체적으로 살펴보겠습니다. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

66 Adaptive Beam-Forming Algorithms
Month Year doc.: IEEE yy/xxxxr0 March 2006 Adaptive Beam-Forming Algorithms DOA Based Sample Matrix Inversion (SMI) Algorithm where is the steering vector for incident angle q and is the estimated interference-plus-noise covariance matrix. Reference Signal Based SMI Algorithm where is the correlation vector and is the estimated covariance matrix. Reference signal is required! 이는 두 신호의 방위각이 각각 10도와 20도 에서 입사한 경우 MUSIC Minimum-norm, CBF 알고리즘 성능을 비교한 것입니다. 이를 통하여 CBF는 도래각을 분리 추정할 수 없으며, High-resolution algorithm은 모두 수신 신호의 도래각을 분리, 추정함을 알 수 있습니다. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

67 Adaptive Beam-Forming Performance Summary
March 2006 Adaptive Beam-Forming Performance Summary Performance summary was presented in January 2006 [doc.: IEEE /0005r1] Efficient CCI cancellation by simple adaptive beam-forming algorithms In uplink, the reference signal method seems more effective due to Simplicity in implementation Robustness to calibration errors due to self-healing nature However, in case of a very large delay spread, the DOA based approach seems preferable. Selective usage according to environments may be necessary. In downlink, the DOA based adaptive beam-forming seems more desirable. Robustness to calibration errors in downlink ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

68 Figure. Block diagram of an STBC-OFDM system
Month Year doc.: IEEE yy/xxxxr0 March 2006 General STBC Figure. Block diagram of an STBC-OFDM system ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

69 STBC Performance Summary
March 2006 STBC Performance Summary Performance summary was presented in January 2006 [doc.: IEEE /0005r1] 2K FFT OFDMA, 2 OFDM symbols preamble, and channel estimation Partitioned MMSE estimation performed by using the preamble SNR in MMSE: 20dB RMS delay parameter in MMSE: 9ms About 3 –7dB downlink gain for r=0.7, when employing (2 x 1) STBC scheme. Additional ~2.5dB gain when employing (2 x 1) closed loop transmit diversity. Even in a highly correlated case, for example r=0.9, the performance improvement is rather significant. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

70 Full Diversity Full Rate Scheme
March 2006 Full Diversity Full Rate Scheme While Space-Time Coding (STC) aims for transmit diversity gain, Spatial Multiplexing (SM) increases the throughput in MIMO channels. Full Diversity Full Rate (FDFR) schemes strike both the diversity and multiplexing at the same time. In FDFR, complexity at the receiver is much higher than SM. We propose a scheme, which facilitates successive interference cancellation at the receiver with slight loss in rate. Thus, the proposed scheme is FD but almost FR. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

71 Basic Transmit Beamforming (BTB)
March 2006 Basic Transmit Beamforming (BTB) In DL, beamformer only directs transmission to the path/cluster with the strongest gain per user. Other directions are suppressed – reducing overall delay Frequency domain beamforming for each user (subchannel) – different directions ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

72 Transmit Beamforming with Diversity/Spatial Multiplexing
March 2006 Transmit Beamforming with Diversity/Spatial Multiplexing In DL, beamformers direct transmission several pathss/cluster Uncorrelated eigen-channels may be used for diversity transmission (CDD) or spatial multiplexing. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

73 Beamforming with Channel Delay Management
March 2006 Beamforming with Channel Delay Management When the overall channel delay exceeds the cyclic prefix period, spatial resolution of multipaths in the angular domain allows to alleviate the inter-block interference. Reflector 1 Or repeater Reflector 2 CPE Rich local scatters Beam 1 Beam 2 Delay 1 T1 = τ1+ D1 Delay 2 T2 = τ2+ D2 Overall Delay |T1-T2| +δ Pre-alignment & beamforming Stream 1 Stream 2 By adjusting timings D1 and D2, the overall delay of the channel can be changed. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

74 Uplink SDMA (formerly Virtual MIMO)
March 2006 Uplink SDMA (formerly Virtual MIMO) Uplink Multiple Antennas at BS and single antenna at each CPE Multiple CPEs share the same physical channel Spectrum efficiency increase linearly with CPE number if the CPE number is less than the number of BS antennas Base CPE 1 CPE 2 ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

75 IEEE 802.16e Uplink Channel Sounding
March 2006 IEEE e Uplink Channel Sounding Presented in January 2006: _Uplink_Channel_Sounding.ppt ULCS is a means of providing channel response information to the BS on an as-needed basis CPE transmits sounding waveform on the UL to enable the BS to measure the channel response Intended for TDD systems where UL&DL RF reciprocity can be leveraged ULCS enables Closed-Loop Transmit Antenna Array Techniques on the DL in TDD: Baseband digital transmit beamforming Transmit Spatial Division Multiple Access (SDMA) Closed-loop Multiple Input Multiple Output (MIMO) ULCS provides an easier and better-performing alternative to other e Closed-Loop techniques with minimal added complexity to the CPE Lower channel measurement delay Better frequency-response tracking Future-Proof: Transmit array algorithms can be upgraded at the BS with no impact on CPE Technique is independent of the number of BS antennas Handles asymmetric bandwidth occupancy of UL&DL transmissions ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

76 Multiple antennas on-going work
March 2006 Multiple antennas on-going work A spatial channel model for the WRAN is currently under development by the joint proposers. Supporting features, such as uplink channel sounding, specific preamble design, MAC messages. Performance evaluation and selection of the proposed schemes. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

77 Spectrum Sensing March 2006
ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

78 Spectrum Sensing : Fact
March 2006 Spectrum Sensing : Fact Spectrum sensing should be accurate enough to protect incumbent users Spectrum sensing should be fast enough to support the sensing protocol in MAC Spectrum sensing block should be able to be implemented by reasonable cost/resources “Spectrum sensing technology” is implementation technology. There is no single sensing technology can meet all the sensing requirement. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

79 Spectrum Sensing : What we proposed
March 2006 Spectrum Sensing : What we proposed We proposed a “sensing system architecture”, not an individual sensing technology, which we believe is the most efficient way to support MAC while sustain accuracy. Within this system architecture, multiple sensing technologies can be chosen to meet the sensing requirements (time, sensitivity) by the manufacturer We’ve been trying to include various sensing technologies for primary user group to feel comfortable on WRAN ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

80 Sensing Receiver Architecture
Month Year doc.: IEEE yy/xxxxr0 March 2006 Sensing Receiver Architecture Omni Antenna Fine/Feature MAC RFE Control Energy Detection ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

81 Spectrum Sensing Strategy
Month Year doc.: IEEE yy/xxxxr0 March 2006 Spectrum Sensing Strategy Begin Sensing Energy Detection for wide band (Analog, RSSI, MRSS, FFT…) Fine/Feature Detection for single channel MAC (Select single channel) Spectrum Usage Database (BS) FFT CSFD Field Sync Optimum Radiometer Spectral Correlation AAC ATSC Segment Sync Multi-cycle Detector Y occupied? End Sensing N ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

82 List of sensing techniques included in the proposal
Month Year doc.: IEEE yy/xxxxr0 March 2006 List of sensing techniques included in the proposal Energy detection Analog integrator MRSS (Samsung/GT) RSSI (Philips) FFT Fine/Feature Detection Cyclo-Stationary Feature Detection (Samsung) Field-sync detection (Philips) ATSC Segment Sync (Thomson) FFT based (Philips and Huawei) Optimum radiometer (France Telecom) Multi-cycle detector (France Telecom) Analog Auto-Correlation (Samsung/GT) Spectral correlation (Huawei) ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

83 Spectrum Sensing : What we will do
March 2006 Spectrum Sensing : What we will do Each of the sensing technology will be rigorously evaluated by the procedure to be defined. Individual sensing technologies that pass the evaluation process shall be included the draft as an optional. Our proposal is open to new innovative sensing technology. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

84 March 2006 Backup Slides ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

85 Equal Gain Beamformer For Multiple Streams
March 2006 Equal Gain Beamformer For Multiple Streams Let received vector be: NT: No. of transmit antennae. NR : No. of receive antennae (assumed here to be = no of streams) H is the channel matrix (NR X NT), Q is the beamforming matrix (NT X NR). x is the data vector (NR X 1), Transmitted vector: Equal-gain constraint implies that each row of Q has the same power. Let H = USVH be the SVD of H. Then, if NT = NR, and Q = V, we get equal gain beamforming because V is an orthonormal matrix. If NT > NR, and Q = V(:, 1:NR), then each row of Q does not have the same power => unequal gains. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

86 Quantized Equal-Gain Beamformer Simulation Scenario
March 2006 Quantized Equal-Gain Beamformer Simulation Scenario 2K FFT, 64 tones per user, all tones used for data transmission. ¼ cyclic prefix. Subchannelization: 16 groups of 4 tones, equally spaced over 6 MHz bandwidth. Each packet simulated had a randomly generated subcarrier set. Channel: 2msec RMS delay spread (total impulse response spread = 20msec), exponential Rayleigh fading, uncorrelated channels from each antenna. 1000 byte packets, each packet goes through a different channel realization, simulation run until 100 packet errors are accumulated. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

87 Quantized Equal-Gain Beamformer Performance
March 2006 Quantized Equal-Gain Beamformer Performance ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

88 CL SDMA Flowchart March 2006 CSI = channel state information
CQI = channel quality indicator ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

89 March 2006 Performance of downlink closed-loop SDMA with correlated fading at the transmitter 3GPP LTE suburban-macro small-scale fading channel model (mean CINR = 7.5 dB) ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

90 Adaptive Beam-Forming (2)
Month Year doc.: IEEE yy/xxxxr0 March 2006 Adaptive Beam-Forming (2) Adaptive array vs. Fixed-beam array More Efficient CCI Suppression: Adaptive array system steers the main beam to the direction of a desired signal, while steering nulls to the directions of undesired signals. 그럼 이번 연구의 내용인 HPi system을 위한 적응 빔 형성 알고리즘에 대하여 설명하겠습니다. 이 그림은 HPi systme의 상향 링크용 스마트 안테나 알고리즘으로서 이는 High-resolution DOA algorithm에 기반을 두었습니다. 그래서 먼저 원하는 신호와 간섭 신호의 도래각을 추정한 후 원하는 신호의 방향으로는 main beam을 형성하고 간섭 신호의 방향으로는 null을 형성하는 알고리즘 입니다. 먼저 배열 안테나를 이용하여 신호를 수신한후, FFT를 취합니다. 그리고 원하는 신호의 주파수 bin을 추출신호가 있는 주파수를 선택하여 covariance matrix를 추정합니다. Covariance matrix에 대하여 eigen-decomposition 과정을 거친후 DOA를 추정합니다. 추정된 DOA를 통하여 간섭과 잡음의 covariance matrix를 생성 합니다. 그후, 생성된 covariance matrix를 이용하여 beam-forming weight vector를 계산합니다. 그리고 계산된 weight vector를 이용하여 beam pattern을 형성합니다. 이 알고리즘에 대하여 약간 구체적으로 살펴보겠습니다. Figure. Adaptive array vs. fixed-beam array ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

91 ABF Performance Evaluation
Month Year doc.: IEEE yy/xxxxr0 March 2006 ABF Performance Evaluation Antenna Array Array type: Linear equi-spaced array with half wavelength spacing consisting of 8 antenna elements. Root-MUSIC is used to estimate the DOAs of incident signals. All incident signals are assumed to have zero elevation angle. Angular Spread Laplacian model All clusters are assumed to have the angular spread of 0.3o. Others No. of OFDM symbols for reverse link preamble is 1. No. of sub-carriers assigned to users is 256. No. of sub-carriers per sub-band is 16 for reference signal method. No channel coding employed 이는 두 신호의 방위각이 각각 10도와 20도 에서 입사한 경우 MUSIC Minimum-norm, CBF 알고리즘 성능을 비교한 것입니다. 이를 통하여 CBF는 도래각을 분리 추정할 수 없으며, High-resolution algorithm은 모두 수신 신호의 도래각을 분리, 추정함을 알 수 있습니다. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

92 Channel Parameters for ABF Simulation (1)
Month Year doc.: IEEE yy/xxxxr0 March 2006 Channel Parameters for ABF Simulation (1) ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

93 Channel Parameters for ABF Simulation (2)
Month Year doc.: IEEE yy/xxxxr0 March 2006 Channel Parameters for ABF Simulation (2) ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

94 Performance Evaluation : ABF Algorithms (1)
Month Year doc.: IEEE yy/xxxxr0 March 2006 Performance Evaluation : ABF Algorithms (1) 이는 두 신호의 방위각이 각각 10도와 20도 에서 입사한 경우 MUSIC Minimum-norm, CBF 알고리즘 성능을 비교한 것입니다. 이를 통하여 CBF는 도래각을 분리 추정할 수 없으며, High-resolution algorithm은 모두 수신 신호의 도래각을 분리, 추정함을 알 수 있습니다. Figure. Comparison of BER performance for reverse link (INR = 25dB, interference DOAs =(20o, 30o), relative amplitude = (0dB, -3dB) ) ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

95 Performance Evaluation : ABF Algorithms (2)
Month Year doc.: IEEE yy/xxxxr0 March 2006 Performance Evaluation : ABF Algorithms (2) Perfect interference cancellation : Output SINR = 24dB 이는 두 신호의 방위각이 각각 10도와 20도 에서 입사한 경우 MUSIC Minimum-norm, CBF 알고리즘 성능을 비교한 것입니다. 이를 통하여 CBF는 도래각을 분리 추정할 수 없으며, High-resolution algorithm은 모두 수신 신호의 도래각을 분리, 추정함을 알 수 있습니다. Figure. Average output SINR vs. azimuth difference for reverse link ( Profile A, SNR = 15dB, INR = 25dB, relative amplitude = (0dB, -3dB) ) ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

96 Performance Evaluation : ABF Algorithms (3)
Month Year doc.: IEEE yy/xxxxr0 March 2006 Performance Evaluation : ABF Algorithms (3) Error distribution: truncated Gaussian Ref. signal method: insensitive due to self-healing nature DOA based method: relatively insensitive 이는 두 신호의 방위각이 각각 10도와 20도 에서 입사한 경우 MUSIC Minimum-norm, CBF 알고리즘 성능을 비교한 것입니다. 이를 통하여 CBF는 도래각을 분리 추정할 수 없으며, High-resolution algorithm은 모두 수신 신호의 도래각을 분리, 추정함을 알 수 있습니다. Figure. Channel mismatch effect for reverse link ( Profile A, INR = 25dB, interference DOAs = (20o, 30o), relative amplitude = (0dB, -3dB) ) ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

97 Performance Evaluation : ABF Algorithms (4)
Month Year doc.: IEEE yy/xxxxr0 March 2006 Performance Evaluation : ABF Algorithms (4) Error distribution: truncated Gaussian Ref. signal method: extremely sensitive DOA based method: relatively insensitive 이는 두 신호의 방위각이 각각 10도와 20도 에서 입사한 경우 MUSIC Minimum-norm, CBF 알고리즘 성능을 비교한 것입니다. 이를 통하여 CBF는 도래각을 분리 추정할 수 없으며, High-resolution algorithm은 모두 수신 신호의 도래각을 분리, 추정함을 알 수 있습니다. Figure. Effect of channel mismatch for forward link ( Profile A, INR = 25dB, interference DOAs = (20o, 30o), relative amplitude = (0dB, -3dB) ) ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

98 Performance Evaluation : STBC (1)
Month Year doc.: IEEE yy/xxxxr0 March 2006 Performance Evaluation : STBC (1) Performance gain: 3.7dB ~ 7.5dB at 10-2 ~ 10-3 BER Figure. BER performance of Alamouti’s scheme in environments (QPSK, degree of correlation r = 0.7) ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

99 Performance Evaluation : STBC (2)
Month Year doc.: IEEE yy/xxxxr0 March 2006 Performance Evaluation : STBC (2) Performance gain: 3.4dB ~ 7.0dB at 10-2 ~ 10-3 BER Figure. BER performance of Alamouti’s scheme in environments (16QAM, degree of correlation r = 0.7) ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

100 Performance Evaluation : STBC (3)
Month Year doc.: IEEE yy/xxxxr0 March 2006 Performance Evaluation : STBC (3) Performance gain: 3.1dB ~ 6.0dB at 10-2 ~ 10-3 BER Figure. BER performance of Alamouti’s scheme in environments (64QAM, degree of correlation r = 0.7) ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

101 Performance Evaluation : STBC (4)
Month Year doc.: IEEE yy/xxxxr0 March 2006 Performance Evaluation : STBC (4) Figure. BER performance vs. degree of correlation in environments (Profile A, QPSK) ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

102 Degree of Correlation vs. Antenna Separation
March 2006 Degree of Correlation vs. Antenna Separation Figure. Degree of correlation vs. antenna separation for various angular spreads (Laplacian model, zero nominal azimuth angle) ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

103 March 2006 FDFR The combination of pre-coder and the delay elements makes the error matrices full rank.  FD. The loss by the tail edges becomes negligible as the block size increases. The interference from the previous vectors are subtracted while that from the later vectors are suppressed. The symbols within a vector are jointly decoded via ML, sphere decoder or any types of linear decoder. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

104 Presentation Outline PHY Proposal Updates to the MAC Proposal
March 2006 Presentation Outline PHY Proposal Updates to the MAC Proposal Conclusions ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

105 March 2006 Disclaimer The following set of slides are restricted to describe only the updates to the MAC proposal described in documents and (presented in January/2006) The following updates together with document represent the entire joint ETRI-France Telecom-I2R-Motorola-Philips-Samsung-Thomson MAC proposal ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

106 MAC Presentation Outline
March 2006 MAC Presentation Outline MAC Protocol MAC layer data communication Support for Adaptive Antenna System (AAS) Explicit outband signalling for hidden incumbent detection Channel switch procedure Coexistence Opportunistic in-band sensing Credit tokens based rental protocol for inter-BS dynamic resource sharing Enhanced measurement and channel management capabilities Clarifications Frequency hopping Support for Single Channel CPEs Quiet period management for sensing Performance Evaluation Synchronization of overlapping BSs CBP ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

107 MAC Presentation Outline
March 2006 MAC Presentation Outline MAC Protocol MAC layer data communication Support for Adaptive Antenna System (AAS) Explicit outband signalling for hidden incumbent detection Channel switch procedure Coexistence Opportunistic in-band sensing Credit tokens based rental protocol for inter-BS dynamic resource sharing Enhanced measurement and channel management capabilities Clarifications Frequency hopping Support for Single Channel CPEs Quiet period management for sensing Performance Evaluation Synchronization of overlapping BSs CBP ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

108 March 2006 MAC Highlights Some aspects of MAC have been inspired by the MAC E.g., Frame format and QoS model However, major enhancements have been made A new superframe structure for better coexistence and self-coexistence, synchronization, Part 74 beacon support, support for bonding, etc. Support for multiple channel operation (contiguous or not) Enhanced support for Adaptive Antenna System Coexistence with both incumbents and itself (self-coexistence); Incumbent user avoidance and Spectrum measurements (incumbents and itself) Channel classification and Management Dynamic resource sharing, Coexistence Beacon Protocol (CBP), and Etiquette Synchronization of overlapping BSs and quiet periods Two-stage fast and fine sensing mechanism and opportunistic sensing Embedded wireless microphone beacon mechanism Clustering support ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

109 Support for Adaptive Antenna System (AAS)
March 2006 Support for Adaptive Antenna System (AAS) Optional mode MAC takes advantage of the increased capacity and range offered by AAS Similar to e Frame structure simultaneously support AAS and non-AAS traffic ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

110 Support for Adaptive Antenna System (AAS)
March 2006 Support for Adaptive Antenna System (AAS) For AAS downlink synchronization, a CPE utilizes the broadcast preamble For network entry and initialization, two options are possible: CPE receives enough energy from the broadcast channel that allows it to decode control information (e.g., UCD/DCD and maps) Hence, proceeds with network entry and initialization Otherwise, BS shall dedicate a fixed and pre-defined portion of the superframe structure as initial ranging contention slots Sufficient slots are used by the CPE as to allow the BS enough time to beamform towards the CPE CPE shall wait for transmission from BS before retry Network entry and initialization proceeds after that ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

111 Support for Adaptive Antenna System (AAS)
March 2006 Support for Adaptive Antenna System (AAS) Alert-Window (AW) Contention slots for initial ranging Used by AAS CPEs and by single channel CPEs ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

112 Support for Adaptive Antenna System (AAS)
March 2006 Support for Adaptive Antenna System (AAS) Channel state information can be done in two ways: Reciprocity: Assumes the upstream channel state estimation as the downstream channel state Feedback: CPE explicitly transmits the estimated channel to the BS Two channel feedback options are available: New MAC control messages (namely, AAS-CFB-REQ and AAS-CFB-RSP) have been defined Piggybacked together with the existing measurement reports used for incumbents and other systems Bandwidth request, incumbent notifications, measurement reports, etc.: Can be done using either the broadcast allocations or by polling ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

113 Hidden Incumbent Systems
March 2006 Hidden Incumbent Systems A WRAN System is on service in channel x. CR BS sensed some channels and it recognized channel x was available, or BS just started the service based on its database information. Some CPEs inside the incumbent system radio area may not be able to decode the CR BS signal because of strong interference. So, the CPEs cannot report the existence of the incumbent system and current status to the BS. BS cannot recognize this situation because of no information. Also, some incumbent users have experienced interference from the WRAN system. Ch x CPE Incumbent System CR System Not overlapped CR CPE Overlapped CR CPE (cannot decode CR Signal and cannot report anything) Incumbent user ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

114 March 2006 Hidden incumbent case occurs When a BS starts the service,
The BS changes the service channel Candidate channel broadcasting by BS and sensing reports for the candidate bands by CPEs can reduce the possibility of hidden incumbent system. But, BS may change its service channel without notification. Problem CPEs inside the overlapped area are aware of the strong interference by incumbent system. How to report it to BS? Implicit hidden incumbent case detection A BS periodically sends sensing request and all CPEs respond. If a BS did not receive sensing responses from some CPEs, then sends again. After some trials, if still some CPEs don’t respond, BS notices hidden incumbent system appearance and changes the channel. Still there remains some problems  some CPEs power off ( Confuses BS as if hidden incumbent case occurs)  CPEs inside the overlapped area just turn on, hence the BS doesn’t know the existence of CPEs. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

115 Explicit OutBand Signaling for Hidden Incumbent Case Detection
March 2006 Explicit OutBand Signaling for Hidden Incumbent Case Detection Hidden Incumbent System Case Method BS periodically broadcasts the information on current channel in some of other unoccupied channels (e.g. candidate channels). Out-band signal: control signal on the band other than current band. This broadcasting signal follows the same PHY and MAC frame architecture (not to necessitate additional protocol or PHY module). CPEs that are not able to decode the BS’s current service channel try to sense other channels to locate the BS signal. If CPEs receive the explicit out-band broadcast signal, It recognizes the current service channel id. If the current channel is already sensed and is found to be not decodable, then the CPE sends a report to the BS using the upstream in out-band. After noticing the existence of the hidden incumbent, BS changes its service channel to other available band. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

116 BS CPE March 2006 Explicit outband signaling period channel
CPE that cannot decode the current service channel will try to sense other channels Outband Signal broadcast Ch C The CPE finally receives at least one of the periodic outband broadcast signals Ch B Ch A Time Explicit outband signaling period It can be decided by incumbent system detection time requirement. Current Service Channel Outband Signal broadcast Outband Signal broadcast Outband Signal broadcast Outband Signal broadcast Not available Outband Signal broadcast Not available Ch A Ch B Ch C Ch D Ch E Ch F Ch X Ch Y BS Frequency Outband Signal broadcast service signal Report Ch A Ch B Ch C Ch D Ch E Ch F Ch X Ch Y CPE Frequency Not available Not available Not available ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

117 S C H March 2006 Explicit out-band broadcast signal
Follow the usual PHY and MAC frame architecture like in the service channel In SCH: need a flag to differentiate Regular service MAC frame (in service channel) Out-band broadcast signal MAC frame (for broadcasting channel) In DS-Bust: include service channel information Service channel numbers, candidate channel numbers, … Hidden incumbent case report When a CPE receives a out-band signal and if the current service channel is not decodable by the CPE, then Sends “Hidden incumbent report” to BS using the broadcasting US-Burst FCH US-MAP DS - Burst DS- MAP US- Burst S C H ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

118 March 2006 Hidden Incumbent System Report CPE report can be either of
“the current service channel x is not decodable” “the current service channel x is used by a incumbent system” If the CPE can recognize incumbent signal. CPE report can also include sensing result for some other channels. US resource (data-burst) allocation for “hidden incumbent report” report. BS may allocate explicit resource to each CPE after CPE initialization procedure – overhead BS may list up slotted US busts for unknown CPEs, which possibly reply their reports using one of the slotted busts. Slotted US burst size can be determined in accordance with the maximum hidden incumbent report size . CPEs that need to send “hidden incumbent report” contend each other Random back-off to send a message. Some overheads necessary in BS to broadcast out-band signals in different channels. CPEs do not need any change on their implementation. Implicit method can supplement the explicit method. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

119 Channel Switch Procedure
March 2006 Channel Switch Procedure WRAN system build a candidate channel list using distributed sensing. When incumbent users and other WRAN system are detected in the current operating channel, The BS selects a channel CHselect from the candidate channel list, either randomly or based on some algorithms. Randomly selects a wait time twait from a time window [ Tmin, Tmax ] Start a wait timer with Twait as the expiration time Advertises the channel selection using backhaul channel or WRAN air interface before jumping to CHselect. Meanwhile the WRAN system sense CHselect for incumbent signals and other WRAN systems If the channel CHselect is still idle/available, it jumps to CHselect when the wait timer expires. If incumbent signals or other WRAN systems exist in CHselect , it goes back to the beginning to select another channel from the candidate channel list or its previously operated channel if occupied by incumbent users If collision occurs after channel switch, it increase tmax and goes back to the beginning to select another channel from the candidate channel list or its previously operated channel if not occupied by incumbent users Otherwise, it decrease Tmax and remove CHselect from the candidate channel list. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

120 March 2006 ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson
Detect incumbent users and other WRAN system on the current operating channel Selects a channel CHselect from the candidate channel list Randomly selects a wait time Twait from a time window [ Tmin, Tmax ] Start a wait timer with Twait as the expire time Stop the wait timer Add previously operating channel not occupied by incumbents to the candidate channel list Advertise the channel selection CHselect Sense channel CHselect Remove CHselect from the candidate channel list no Channel CHselect idle? yes no Wait timer expire? yes Switch to channel CHselect yes Increase Tmax Incumbent users and other WRAN system on Channel CHselect? no Remove CHselect from the candidate channel list and reduce Tmax Stop ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

121 MAC Presentation Outline
March 2006 MAC Presentation Outline MAC Protocol MAC layer data communication Support for Adaptive Antenna System (AAS) Explicit outband signalling for hidden incumbent detection Channel switch procedure Coexistence Opportunistic in-band sensing Credit tokens based rental protocol for inter-BS dynamic resource sharing Enhanced measurement and channel management capabilities Clarifications Frequency hopping Support for Single Channel CPEs Quiet period management for sensing Performance Evaluation Synchronization of overlapping BSs CBP ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

122 The Opportunistic In-band Sensing Scheme
March 2006 The Opportunistic In-band Sensing Scheme Applicable for those cases where the traffic is low, and so sensing can take place within a frame For these cases, the opportunistic in-band sensing can have performance benefits such as reducing detection time and improving detection accuracy This scheme may be able to run in parallel with the out-of-band sensing algorithm: However, whenever there is contention between the opportunistic in-band sensing and out-of-band sensing, out-of-band sensing shall take precedence ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

123 The Opportunistic In-band Sensing Scheme (cont.)
March 2006 The Opportunistic In-band Sensing Scheme (cont.) The main idea is to use common “sensing-eligible” frames to do in-band sensing A “sensing-eligible” frame is: A frame with no traffic, i.e. no US or DS traffic A frame at which the backlogged traffic (both US and DS) is less than the remaining capacity in the current superframe and no sensing frame has been allocated in the superframe The last frame of the superframe and no sensing frame has been allocated in the superframe A “sensing-eligible” frame is designated as a sensing frame if it is not marked for use for out-of-band sensing ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

124 The Opportunistic In-band Sensing Scheme (cont.)
March 2006 The Opportunistic In-band Sensing Scheme (cont.) The opportunistic in-band sensing scheme ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

125 Month Year doc.: IEEE yy/xxxxr0 March 2006 Credit Tokens based Rental Protocol for Inter-BS Dynamic Resource Sharing Rental Protocol Offeror Renter Problem: How to deal access/usage contention issues when several renters compete to access to the same offer at the same time ? How to schedule the competing renters in a fair fashion while maximizing the spectrum efficiency ? The proposed mechanism complements the existing proposal It introduces a cooperative sharing negotiation protocol: credit tokens based rental protocol between one offeror and several renters ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company

126 March 2006 Credit Tokens based Rental Protocol for Inter-BS Dynamic Resource Sharing (cont.) Definition Radio channel: time*frequency. BIN = time unit*frequency unit. A radio channel = a number of BINs. Credit Tokens (CT): « money like » unit. What can be shared/negotiated? Number of BINs for a given time duration. The starting time of the sharing. The ending time of the sharing. Principles Each offeror and renter BS is prior allocated with a given credit tokens budget. A BIN is charged as a number of CT per time*frequency unit. A radio channel can be shared by exchanging CT between offeror and renter. The exchange is dynamic and supported through the CT transactions. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

127 March 2006 Credit Tokens based Rental Protocol for Inter-BS Dynamic Resource Sharing (cont.) Principles Transactions rely on the real time and dynamic usage of reserve price auctionning and bidding mechanisms (e.g. ascending bid auction) to solve contention issues between renters BSs: Offeror = auctionner Renter = bidder BSs do not manipulate money. CT is used for self coordination in a distributed fashion between BS (self gouvernance). Incentive for sharing and fairness support is achieved through CT awarding. The credit tokens usage at each BS is ruled by the radio etiquette. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

128 Credit Tokens based Scheduling Cycle
March 2006 Credit Tokens based Scheduling Cycle based auctioning/bidding First iteration (n = 1) of the dynamic credit tokens phase expressing Interest (1) Awareness/Advertising (3) Inform bidding phasing (2) Express interest (5) 1st Bidding results (4) Express initial bidding Offeror BS Renter BS Advertising phase Resource Usage phase (10) BW Granting (9) Transaction (8) Final Bidding results/Pricing (5) (n-1)th Bidding results (6) Express new bidding (nth) (7) nth Bidding results Offeror BS Renter BS nth iteration (n > 1) of the dynamic credit tokens based auctioning/bidding phase Final pricing and Transaction phase Credit tokens based BW Granting phase ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

129 March 2006 Credit Tokens based Rental Protocol for Inter-BS Dynamic Resource Sharing (cont.) This credit tokens based rental protocol can be implemented: either over the air (MAC level) or the backhaul (wired) For the over air implementation, the credit tokens based rental protocol rules the MAC frame structure sharing between renters and offerors Scalable for different resoure renting timescales Different auctioning strategies can be applied depending on the time constraints for the negotiation Credit token charging mechanisms (different auctioning strategies) can be dynamically tuned to the context through the radio etiquette Space time traffic intensity variations in each cell Number of bidders ... ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

130 Enhanced Measurement Capability
March 2006 Enhanced Measurement Capability Besides the detailed and on-channel report, a CPE can now send a Consolidated Spectrum Occupancy Report A Consolidated Spectrum Occupancy Report conveys a summary of the overall spectrum occupancy from the point of view of a CPE For a particular channel, the CPE reports its state as a 3 bit field: Unmeasured Vacant Occupied (i.e., energy detected) Occupied by an Incumbent Occupied by ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

131 Enhanced Channel Management Capability
March 2006 Enhanced Channel Management Capability Based on the measurement reports from CPEs, a BS can transmit a Channel Occupancy Update message to CPEs Allows quicker recovery, more efficient measurements, etc. Similar to a CPE, for a particular channel the BS reports its state as a 3 bit field: Unmeasured Vacant Occupied (i.e., energy detected) Occupied by an Incumbent Occupied by ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

132 MAC Presentation Outline
March 2006 MAC Presentation Outline MAC Protocol MAC layer data communication Support for Adaptive Antenna System (AAS) Explicit outband signalling for hidden incumbent detection Channel switch procedure Coexistence Opportunistic in-band sensing Credit tokens based rental protocol for inter-BS dynamic resource sharing Enhanced measurement and channel management capabilities Clarifications Frequency hopping Support for Single Channel CPEs Quiet period management for sensing Performance Evaluation Synchronization of overlapping BSs CBP ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

133 Frequency Hopping Purpose
March 2006 Frequency Hopping Purpose To dismiss any presumption that the proposed MAC does not allow frequency hopping Treated as an optional implementation issue provided the technical hurdles can be overcome In order to avoid an in-band quiet period, a WRAN may hop to a Channel A provided: The Channel A evaluation meets the Channel Availability Check Time as specified in the FRD The Channel A is not occupied by any incumbent The Channel A is not occupied by any network Otherwise, it may be worse than sticking to your current channel Adjacent channels have also been checked for the presence of incumbents, as to adhere to the EIRP profile ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

134 Support for Single Channel CPE
March 2006 Support for Single Channel CPE At this point, channel bonding (of up to 3 contiguous TV channels) is an optional feature This implies that BSs and CPEs may have different capabilities What happens if a BS is in channel bonding mode when a single channel CPE attempts to joint the network? To support this feature, an Alert Window (AW) is added to the superframe structure Used to notify the BS about incoming CPEs who cannot operate in the same mode as the BS ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

135 Support for Single Channel CPE (cont.)
March 2006 Support for Single Channel CPE (cont.) Alert-Window (AW) Contention slots for initial ranging Used by AAS CPEs and by single channel CPEs ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

136 Quiet Period Management for Sensing
March 2006 Quiet Period Management for Sensing Background A potentially very large number of channels (up to N±15) have to be periodically sensed for the presence of incumbents At the same time, support to QoS traffic requires delays as low as 20ms (see FRD) Question How is sensing done as to meet these requirements? Answer Sensing is a two-stage process Stage 1: Fast sensing (e.g., energy detection) Stage 2: Only if needed, perform fine sensing (feature detection) ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

137 Quiet Period Management for Sensing (cont.)
March 2006 Quiet Period Management for Sensing (cont.) Quiet period structure The fast sensing is performed in-band only May or may not be scheduled by the BS (e.g., between two consecutive MAC frames) Upon BS request, a consolidated report on the fast sensing outcome is sent by CPEs BS then determines the need for the next fine sensing and how much time is required ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

138 Quiet Period Management for Sensing (cont.)
March 2006 Quiet Period Management for Sensing (cont.) ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

139 Quiet Period Management for Sensing (cont.)
March 2006 Quiet Period Management for Sensing (cont.) Since quiet periods from overlapping cells are synchronized, sensing is highly effective ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

140 Quiet Period Management for Sensing (cont.)
March 2006 Quiet Period Management for Sensing (cont.) Given that the nature of incumbent appearance on a channel is sparse (e.g., new TV stations do not come on the air every hour): The fast sensing stage will be enough most of the time Hence, the fine sensing stage will not need to be performed Even if the fine sensing stage is required to be performed, its duration will exactly fit how much is required to be measured Therefore, with this mechanism: Not only will incumbents have their protection guaranteed The stringent QoS requirements specified in the FRD will be met ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

141 MAC Presentation Outline
March 2006 MAC Presentation Outline MAC Protocol MAC layer data communication Support for Adaptive Antenna System (AAS) Explicit outband signalling for hidden incumbent detection Channel switch procedure Coexistence Opportunistic in-band sensing Credit tokens based rental protocol for inter-BS dynamic resource sharing Enhanced measurement and channel management capabilities Clarifications Frequency hopping Support for Single Channel CPEs Quiet period management for sensing Performance Evaluation Synchronization of overlapping BSs CBP ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

142 Performance Evaluation
March 2006 Performance Evaluation Two aspects of the proposal are further evaluated Distributed synchronization of overlapping cells Four (4) step-by-step scenarios Overall convergence time for tens of thousands of scenarios Additional CBP protocol evaluation, which assesses Self-coexistence Distributed quiet period synchronization of overlapping cells ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

143 Synchronization of Overlapping WRANs
March 2006 Synchronization of Overlapping WRANs For all simulations Number besides a node is the superframe transmission time (STT) Red line between nodes means nodes in range and STT NOT aligned Blue line between nodes means nodes in range and STT aligned Units Time is milliseconds Space is kilometers ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

144 Synchronization of Overlapping WRANs: Scenario 1
March 2006 Synchronization of Overlapping WRANs: Scenario 1 A total of 24 WRANs are considered BSs and CPEs have a radio range of 25 Km ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

145 March 2006 ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

146 Synchronization of Overlapping WRANs: Scenario 2
March 2006 Synchronization of Overlapping WRANs: Scenario 2 A total of 30 WRANs are considered All WRANs power up at the same time (worst case analysis) BSs and CPEs have a radio range of 20 Km ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

147 March 2006 ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

148 Synchronization of Overlapping WRANs: Scenario 3
March 2006 Synchronization of Overlapping WRANs: Scenario 3 A total of 10 WRANs are considered All WRANs power up at the same time (worst case analysis) Random STT at startup BSs and CPEs have a radio range of 20 Km ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

149 March 2006 ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

150 Synchronization of Overlapping WRANs: Scenario 4
March 2006 Synchronization of Overlapping WRANs: Scenario 4 A total of 10 WRANs are considered All WRANs power up at the same time (worst case analysis) Random STT at startup BSs and CPEs have a radio range of 20 Km ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

151 March 2006 ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

152 March 2006 ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

153 March 2006 ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

154 March 2006 ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

155 March 2006 ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

156 March 2006 ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

157 March 2006 ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

158 March 2006 ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

159 Synchronization of Overlapping WRANs: Overall Convergence Time
March 2006 Synchronization of Overlapping WRANs: Overall Convergence Time Comprehensive evaluation of the synchronization mechanism Used for self-coexistence (e.g., CBP) as well as for quiet periods Results show the quick convergence and efficiency of the algorithm A similar scheme is used in the WiMedia UWB MAC ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

160 March 2006 CBP/Synchronization Evaluate the self-coexistence mechanisms of the proposed MAC Synchronization CBP in every frame The number of overlapping cells are progressively increased Up to 4 cells are simulated BSs and CPEs start at random Network is fully loaded and traffic is uniform 1 cell: 2 cells: ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

161 CBP/Synchronization (cont.)
March 2006 CBP/Synchronization (cont.) 3 cells: 4 cells: ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

162 CBP/Synchronization (cont.)
March 2006 CBP/Synchronization (cont.) Simple scheduler CBP together with Synchronization can provide significant performance improvements Since CBP is under control of the BS, it can be made adaptive ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

163 Presentation Outline PHY Proposal Updates to the MAC Proposal
March 2006 Presentation Outline PHY Proposal Updates to the MAC Proposal Conclusions ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson

164 Conclusions Presented the PHY proposal and updates to the MAC proposal
Month Year doc.: IEEE yy/xxxxr0 March 2006 Conclusions Presented the PHY proposal and updates to the MAC proposal The proposal contains numerous mechanisms to protect incumbents while meeting the requirements set forth by the WG PHY Based on OFDMA Flexible channel configurations TV and Part 74 service detection and protection MAC Coexistence is a key feature Incumbent protection Self-coexistence CBP, dynamic resource sharing, channel bonding, etc. ETRI, FT, I2R, Motorola, Philips, Samsung, Thomson John Doe, Some Company


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