Presentation is loading. Please wait.

Presentation is loading. Please wait.

LAN LAN 2001. 9. 11 (02) 820-5299 21.

Similar presentations

Presentation on theme: "LAN LAN 2001. 9. 11 (02) 820-5299 21."— Presentation transcript:

1 LAN LAN (02)



4 Wireless Access Beyond 3 rd Generation

5 Wireless Data Solutions

6 Standardization of Broadband Wireless Access Network

7 BRAN (1) BRAN, ISDN : 25Mbps 155Mbps : ATM 16Kbps 16Mbps LAN ATM IP : OFDM Medium Access Control (MAC) AP (Access Point) Scheduler ( ) Dynamic Reservation TDMA/TDD

8 BRAN (2) Type HIPERLAN/1 - : 19 Mbps - MAC : CSMA/CD - : GMSK - : 200 m - : 5.2 GHz ( ) ETS ISO Mbps LAN HIPERLAN/2 - : 6-54 Mbps - MAC : Dynamic Reservation TDMA/TDD - : OFDM - : 200 m - : 5.2GHz ( ) EP-BRAN HIPERLAN/1 - IMT-2000, ATM, IP - WATM-WG ATM HIPERACCESS / HIPERMAN - : 25 Mbps - MAC : Dynamic Reservation TDMA/TDD - : 5 Km ( ) - : GHz EP-BRAN ( ) - / (B-WLL) - HIPERACCESS for LOS : milimeter wave - HIPERMAN for NLOS : below 10 GHz - IEEE HIPERLINK - : 155 MHz - MAC : Dynamic Reservation TDMA/TDD - : 150 m - : 17.1 GHz ( ) EP-BRAN HIPERACCESS HIPERLAN (155 Mbps)

9 Standardization of IEEE Task Group IEEE TG a - IEEE U-NII 5GHz 6~54Mbps OFDM - ETSI BRAN, MMAC - NTT, Lucent, BreezeCom IEEE TG b - IEEE GHz 10Mbps Alantro, Lucent/Harris, Micrilor IEEE TG d - regulatory domains (countries) IEEE TG e - QoS MAC - Security IEEE TG f - Inter AP Protocol IEEE TG g GHz 20 Mbps - Intersil OFDM TI PBCC IEEE TG h - DFS TPC

10 MMAC : Multimedia Mobile Access Communication Ultra high speed, high quality Multimedia information anytime and anywhere with seamless connections to optical fiber networks Launch target date : 2002 MMAC - PC (MMAC Promotion Council) Technical Committee High Speed Wireless Access 30Mbps SHF 3-60 GHz Ultra High Speed Wireless LAN 155Mbps ATM LAN (30 – 300GHz) 5GHz Band Mobile Access 20 – 25Mbps ATM LAN 5GHz Wireless Home-link PC / 100Mbps SHF 3-60 GHz (IEEE1394) MMAC in JAPAN

11 Spectrum Allocation in 5GHz 20Mhz Channel separation few carrier frequencies Coexistence with other radio systems Need for a Dynamic Frequency Selection (DFS) Technique

12 Other Forums OFDM Forum To foster a single, compatible OFDM standard, needed to implement cost-effective, high-speed wireless networks on variety of devices Launched in Mar by Wi-LAN, Phillips, Ericsson, Nokia, Samsung EM and Caltrans. Later Alcatel, Intersil, Solectek, Infineon Tech., Motorola joined. HIPERLAN2 Global Forum (H2GF) To drive the adoption of HIPERLAN/2 as a global broadband wireless technology in 5GHz, with bandwidth anywhere between Mbps using OFDM. Launched in Sep by 6 founding members, Bosch, Dell, Ericsson, Nokia, Telia and TI. Later Nortel and Xilinx joined.

13 LAN LAN 5 GHz Task Group 1 : 5 GHz 2 :, 3 : LAN, ETRI : 2 : 3 :

14 IEEE b

15 IEEE Chipset (1) Intersil PRISM Chipset PRISM I 2 Mbps, 2.4 GHz, IEEE PRISM II (5 chip solution) 11 Mbps, 2.4 GHz, IEEE b –HFA3983 – 2.4 GHz Power Amplifier and Detector –HFA3683A – 2.4 GHz RF/IF Converter and Synthesizer (RF/IF) –HFA3783 – IQ Modulator/Demodulator and Synthesizer (IF) –HFA3861B – Baseband Processor with Rake Receiver and Equalizer (BBP) –HFA3842 – MAC PRISM 2.5 (4 chip solution) 11 Mbps, 2.4 GHz, IEEE b –ISL3984 – 2.4 GHz Power Amplifier and Detector (die shrinks) –ISL3685 – 2.4 GHz RF/IF Converter and Synthesizer (die shrinks)

16 IEEE Chipset (2) –HFA3783 – IQ Modulator/Demodulator and Synthesizer –ISL3873 – Integrated MAC and Baseband Processor PRISM 3 (2 chip solution ) 11 Mbps, 2.4 GHz, Direct Down Conversion architecture –ISL3684 – Direct Up/Down Converter – Single Chip PHY –ISL3871 – Integrated Baseband/MAC PRISM Indigo (4 chip solution) 54 Mbps, 5 GHz, IEEE a, HIPERLAN/2 –ISL3987 – 5 GHz Power Amplifier –ISL3877 – MAC with Baseband Processor –ISL3787 – 1.2 GHz IF/BB Converter with AGC and Synthesizer –ISL3687 – 5 GHz RF/IF Converter with Integrated Synthesizer

17 IEEE b (1)

18 IEEE b (2) IEEE b 2.4GHz High Rate PHY Specification High rate extension of the PHY for the DSSS system Direct Sequence Spread Spectrum frequency band: 2.4~2.4835GHz ISM band data rate: 1, 2, 5.5, 11Mbps modulation: DBPSK / DQPSK / CCK 11-chip Barker sequence same occupied channel bandwidth same PLCP preamble and header basic HR/DSSS and DSSS PHY can co-exist in the same BSS optional modes CCK PBCC(Packet Binary Convolutional Coding) shorter PLCP preamble mode (2, 5.5, 11M)

19 IEEE b (3) Modulation Modes 4 possible spreading sequences 64 possible spreading sequences

20 IEEE b (4) Long PLCP PPDU Format SYNC: scrambled one s (scrambler initial state: [ ]) SFD: [ ] preamble and header: 1Mbps DBPSK Short PLCP PPDU Format shortSYNC: 56 bits scrambled zero s (scrambler initial state: [ ]) shortSFD: 16 bits backward SFD preamble: 1Mbps DBPSK / header: 2Mbps DQPSK – 96us - SIGNAL Field X 0A / X 14 / X 37 / X 6E for 1 / 2 / 5.5 / 11 Mbps - CRC Field

21 IEEE b (5) Block Diagram (DSSS) Performance processing gain: 11 (10.4dB) AWGN / Indoor Model

22 IEEE MAC (1) Multiple/random Access Protocol ALOHA : send packet, receive packet, send ACK packet success if no ACK received during 200 ~ 1500ns, fail then retransmit packet after random backoff delay simple but low throughput(max. 18%) for a large no. of stations Multiple/random Access Protocol Slotted ALOHA : max. throughput 37% CSMA : Sense the status of a channel before transmitting (max. 80%) CSMA/CD(IEEE 802.3, Ethernet) : sense the carrier by measuring the current or voltage in the cable CSMA/CA(IEEE ) : avoid collision by random backoff procedure

23 IEEE MAC (2)

24 IEEE MAC (3) Coordination Functions Distributed coordination function(DCF) : contention – based protocol,CSMA/CA DCF with handshaking (DFW : distribution four-way handshake) if collision occurs, far less BW is wasted for a large data MPDU hidden node problem(63%) can be alleviated Point coordination function(PCF) Contention-free(priority-based, polling) access protocol usable on infrastructure network containing a controller called a point coordinator within AP DCF options Never use RTS/CTS Use RTS/CTS whenever MSDU size > RTS_Threshold Always use RTS/CTS

25 IEEE MAC (4) DCF Carrier sense mechanism physical carrier sense (channel assessment) virtual carrier sense : duration field is placed in the station s Network Allocation Vector(NAV) Inter Frame Space(IFS) Short IFS(SIFS) : highest priority level ACK, CTS frame PCF IFS(PIFS) DCF IFS(DIFS) Large MSDU is broken up into multiple fragments

26 IEEE MAC (5)


28 Core network independent with QoS support Support of IP transporting networks, ATM networks, 3 rd Generation, Firewire, etc. Radio access network specifications (physical layer, data link control layer and convergence layer) Interoperability standard with conformance test specifications A cellular multi-cell radio network capable of offering access, switching and management functions within a large coverage area Centralized mode (mandatory) and direct mode (optional) Mobility management Power management - Uplink power control, downlink power setting, sleep mode Capable of handling different interference and propagation situations Link Adaptation with multiple modulation and channel coding schemes HIPERLAN/2 Main Requirements (1)

29 Supporting asymmetrical traffic load fluctuating in uplink and downlink as well as for different users Range of radio cell: m in a typical office indoor environment, 150 m in a large open indoor or typical outdoor environment No frequency planning Dynamic Frequency Selection Multicast and broadcast HIPERLAN/2 Main Requirements (2)

30 HIPERLAN/2 Protocol Architecture Standardization scope : air interface, service interfaces of the radio access system and the convergence layer functions

31 TDMA/TDD with a fixed frame duration of 2 ms 3 transmission possibilities : AP to MT (Downlink), MT to AP (Uplink), and MT to MT (Direct Link) Centralized scheduling (not specified) Air interface frame creation in the AP Resource allocation by the AP Resource requests from MTs Dynamic assignment of capacity in uplink and downlink – no fixed slot structure Could consider QoS and link adaptation modes Random access scheme Association and resource request transmissions from MTs Random access in mobile stations: slotted ALOHA with exponential increase of contention window Peer-to-peer and multicast support Sector antenna support HIPERLAN/2 DLC: Medium Access Control

32 Basic MAC Frame Structure A Single Sector System A Multiple Sectors System

33 Protocol Stack: RLC Functional Entities Association Control Radio Resource Control DLC User Connection Control

34 Main difference between a and HIPERLAN/2: Preamble due to different multiple access scheme Several physical layer modes are provided Link Adaptation selects the most appropriate mode. Physical layer modes of HIPERLAN/2 & IEEE a: Physical Layer Modes ModulationCode rateNet bit rateSystem BPSK1/26 MbpsH/2 and IEEE BPSK3/49 MbpsH/2 and IEEE QPSK1/212 MbpsH/2 and IEEE QPSK3/418 MbpsH/2 and IEEE 16 QAM1/224 MbpsIEEE 16 QAM9/1627 MbpsH/2 16 QAM3/436 MbpsH/2 and IEEE 64 QAM2/348 MbpsIEEE 64 QAM3/454 MbpsH/2 and IEEE


36 Transmission Techniques for Wireless LAN (DSSS, FHSS) OFDM 902 ~ 928 MHz 2.4 ~ GHz ~ GHz ~ GHz 3×10 11 Hz (LED ) 5.15 ~ 5.24 GHz 5.25 ~ 5.35 GHz ~ GHz (ISM ) 105 ~ 800 ft (32 ~ 244 m) 40 ~ 130 ft (12 ~ 40 m) 30 ~ 80 ft (9 ~ 24 m) 80 ~ 600 ft (24 ~ 183 m) - - ( ) - (10Mbps) - - ( ) - DSSS: Chip rate FHSS: - - ( ) - ( ) - - FFT - (, ) Orinoco (Lucent, 11Mbps, DSSS) Altair (Motorola, 10Mbps) Infra LAN (BICC, 4.16Mbps) IEEE a (54Mbps) HIPERLAN/2 (54Mbps)

37 Frequency Division Multiplexing entire bandwidth is divided into many narrow subchannels serial-to-parallel conversion, parallel transmission low bit rate transmission at each subchannel : flat fading ideally bandlimited transmission spectrum: no ISI and ICI practical case: guard band is needed lower bandwidth efficiency Multicarrier Modulation (1)

38 Multicarrier Modulation (2) bandpass filter and oscillator bank scheme 1: high complexity due to the filters with sharp transition scheme 2: orthogonally overlapped spectrum for high bandwidth efficiency and lower filter complexity

39 Orthogonal Frequency Division Multiplexing (1) all subchannels are orthogonally overlapped without bandlimiting filter efficient implementation by use of IFFT / FFT transmission signal is rectangular windowed in time-domain each subchannels spectrum is sinc function

40 Orthogonal Frequency Division Multiplexing (2)

41 Cyclic Prefix (1) OFDM transmission is block processing inter-block interference (ISI) guard interval insertion between two successive OFDM symbols zero-valued guard interval vs. cyclic prefix

42 Cyclic Prefix (2) zero-valued guard interval cyclic prefix no ISI but ICI no ISI and ICI

43 Filtering and Windowing Transmission Spectrum no bandlimits in frequency-domain rectangular window in time-domain large spectrum outside transmission band Filtering or Windowing raised-cosine window in time-domain bandlimit filter in frequency-domain Virtual Carriers unused subcarriers

44 COFDM (1) Frequency-Selective Fading Channel deep fading over several subcarriers burst error: error floor OFDM combined with Forward Error Correction Coding coded OFDM (COFDM) convolutional coding and Reed-Solomon coding concatenated coding, TCM, turbo coding interleaving: bit or/and symbol or/and OFDM symbol


46 Multiple Access Schemes For single carrier systems, multiple access techniques for multi-user system FDMA, TDMA, CDMA (conflict-free access methods) For OFDM systems uplink and downlink : TDD uplink : OFDM/TDMA downlink : OFDM-FDMA, OFDM-TDMA, OFDM-CDMA TDMA : centralized node (Hub) CSMA : peer-to-peer

47 Spatial Division Multiple Access (SDMA) Improves bandwidth efficiency System capacity increases with number of antennas by exploiting spatial diversity Antenna array processing at base station for Tx and Rx OFDM reduces the complexity of baseband SDMA processing

48 Frame Structure of Spatially Extended MAC Protocol

49 OFDM/SDMA Architecture with Per-carrier Processing

50 Applications Military Application (1950s – 1960s) KINEPLEX and Kathryn Broadcasting Digital Audio Broadcasting(DAB), Digital Terrestrial TV Broadcasting(DVB) Wired Communications (DMT) Asymmetric Digital Subscriber Line(ADSL) Very-High-Bit-Rate Digital Subscriber Line(VDSL) Power-Line Communication Wireless ATM and Wireless LAN Magic WAND, IEEE a, HIPERLAN/2, IEEE , Wireless IEEE 1394 Cellular-based Communications Advanced Cellular Internet Service(ACIS) Disadvantages of Multicarrier Transmission Sensitive to carrier frequency offset and timing offset High PAR(peak-to-average ration), sensitive to nonlinear distortion

51 IEEE a

52 IEEE a PHY (1) HIPERLAN/2 Physical layer : OFDM Frequency band : , , GHz U-NII band Data rate : 6, 9, 12, 18, 24, 36, 48, 54 Mbps (variable rate); 6,12,24 Mbps (mandatory) Subcarriers : 52 (N=64) Modulation : BPSK/QPSK/16QAM/64QAM FEC : 1/2, 2/3, 3/4 convolutional code Information data rate 6, 9, 12, 18, 24, 36, 48 and 54 Mbit/s (6, 12, 24 Mbit/s are mandatory) Modulation BPSK-OFDM QPSK-OFDM 16-QAM-OFDM 64-QAM-OFDM Error Correction Code K=7 (64 states) Convolutional code Coding rate 1/2, 2/3, 3/4 Number of subcarriers 52 OFDM symbol duration 4.0 us Guard interval 0.8 us (T GI ) Occupied Bandwidth 16.6 MHz

53 IEEE a PHY (2) IEEE a Data RateModulation Coding rate R Coded bits per subcarrier N BPSC Coded bits per OFDM symbol N CBPS Data bits per OFDM symbol N DBPS 6 Mbit/sBPSK1/ Mbit/sBPSK3/ Mbit/sQPSK1/ Mbit/sQPSK3/ Mbit/s16QAM1/ Mbit/s16QAM3/ Mbit/s64QAM2/ Mbit/s64QAM3/

54 IEEE a PHY (3) OFDM ParameterValue Sampling rate fs=1/T20 MHz Useful symbol part duration T U 64*T 3.2 s Cyclic prefix duration T CP 16*T 0.8 s (mandatory) 8*T 0.4 s (optional) Symbol interval Ts 80*T 4.0 s (T U + T CP ) 72*T 3.6 s (T U + T CP ) Number of data sub-carriers N SD 48 Number of pilot sub-carriers N SP 4 Total number of sub-carriers N ST 52 (N SD + N Sp ) Sub-carriers spacing f MHz (1/ T U ) Spacing between the two outmost sub-carriers MHz (N ST * f )

55 Measurement Site and Location of Antennas

56 Statistics of RMS Delay Spread (threshold=30dB) Ant. Sep.MeanStd. DevMinMax 5MLOS MNLOS MLOS MNLOS MNLOS MNLOS

57 Performance of IEEE a (1) Ideal Condition - AWGN, Hard decision, Truncation depth = 35 - BPSK, QPSK : - M - QAM :

58 AWGN Indoor Channel Performance of IEEE a (2)

59 IEEE a PLCP PLCP Transmit Procedure PLCP Receive Procedure

60 IEEE a PLCP Frame Format IEEE a PPDU IEEE a

61 (1) Signal Detection, AGC (2) Estimate Coarse Carrier Frequency Offset Estimate Symbol Timing Offset (3) Estimate Fine Carrier Frequency Offset Estimate Channel IEEE a Preamble

62 Short Training Symbol (B) Long Training Symbol IEEE a Training Symbols

63 HIPERLAN/2 Broadcast Burst Preamble Enables signal detection, automatic gain control symbol timing synchronization (coarse and fine) carrier frequency synchronization channel estimation and equalization Preamble has a low PAR (3dB) so nonlinearities of PA do not affect AGC

64 H/W Block Diagram for IEEE a Modem

65 H/W Block Diagram for OFDM Modem ASIC

66 Development Environment for OFDM MODEM ASIC Chip Floating Point Simulation SPW, C, MATLAB OFDM simulator Fixed Point Simulation Fixed Point Simulator bit -ADC, DAC, FFT(external, internal), Equalizer, ( symbol, coarse/fine frequency offset, estimator, compensator, tracking) VHDL Coding FPGA APEC 100 Gate, QUARTUS ASIC Chip I&C Tech 0.25 um 208 MQFP package Soft-decision Viterbi detector Full-digital synchronization and tracking On-chip ADC and DAC

67 Block Diagram of OFDM ASIC Chip

68 IEEE vs. HIPERLAN/2 Characteristics b802.11aHIPERLAN/2 ModulationFH/DSSSDSSSOFDM Carrier frequency2.4 GHz 5 GHz Max. physical rate2 Mb/s11 Mb/s54 Mb/s Max. data rate, layer 31.2 Mb/s5 Mb/s32 Mb/s Medium access control / Media sharing CSMA/CA Central resource control / TDMA / TDD ConnectivityConn.-less Conn.-oriented MulticastYes QoS supportPCF ATM / 802.1p / RSVP / DiffServ (full control) AuthenticationNo Encription40-bit RC4 DES, 3DES Handover supportNo Fixed network supportEthernet Ethernet, IP, ATM, UMTS, FireWire, PPP Management MIB HIPERLAN/2 MIB Radio link quality controlNo Link Adaptation

69 LAN LAN RF o 5GHz Access Point/ o 5GHz SSPA CMOS RF (LAN ) o Access Point / MAC o IEEE a HIPERLAN/2 o IEEE a HIPERLAN/2 MAC (54Mbps) o MAC LAN o QoS MAC o DFS TPC o / - /, MIMO, OFDM/SDMA -, - PAPR o LAN TCP o 5GHz LAN - Access Point(802.11a H/2 ) - MAC - MAC - Access Point o LAN Macro Micro o IMT-2000 o IEEE1394 ( 1394) 5GHz TFT

70 ETSI BRAN, Broadband Radio Access Networks(BRAN); HIgh Performance Radio Local Area Network (HIPERLAN) Type 2; requirements and architectures for wireless broadband access and interconnection, TR v2.2.1 Jan ETSI BRAN, Broadband Radio Access Networks(BRAN) HIPERLAN Type 2; Physical (PHY) layer, TS v1.2.1 Nov ETSI BRAN, Broadband Radio Access Networks(BRAN) HIPERLAN Type 2; Data Link Control (DLC) Layer Part 1: Basic Data Transport Functions, TS , v1.1.1 Apr ETSI BRAN, Broadband Radio Access Networks(BRAN) HIPERLAN Type 2; Data Link Control (DLC) Layer Part 2: Radio Link Control (RLC) sublayer, TS , v1.1.1 Apr IEEE a, High Speed Physical Layer in the 5 GHz Band, 1999 ETSI BRAN web page, IEEE web page, OFDM Forum web page, HIPERLAN2 Global Forum web page, OFDM,, 2001 VLSI - CDMA, OFDM, MC-CDMA,, 2001 IEEE a LAN,, 16 10, pp , 1999 LAN (HIPERLAN/2),, 17 11, pp , 2000,, 18 4, 2001 References

Download ppt "LAN LAN 2001. 9. 11 (02) 820-5299 21."

Similar presentations

Ads by Google