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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 1 YC Maa et al., InProComm, Inc. Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs) Submission Title: A Wise AFH Solution for WPAN Date Submitted: November 1, 2001 Source: YC Maa, HK Chen, Shawn Liu and KC Chen Company: Integrated Programmable Communications, Inc. Address:Taiwan Laboratories Address: P.O. Box , Hsinchu, Taiwan 300 TEL , FAX: , {ycmaa, hkchen, shawnliu, Re: [IEEE /367r1, IEEE /082r1, IEEE /246r1, IEEE /252r0, IEEE /366r1, IEEE /382r0, IEEE /385r0, IEEE /386r0, IEEE /443r0, IEEE /471r0, IEEE /491r0] Abstract:This document presents a wise AFH scheme for TG2 Coexistence Mechanism. Purpose:Submission to TG2 for AFH draft consideration. Notice:This document has been prepared to assist the IEEE P 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 acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 2 YC Maa et al., InProComm, Inc. A Wise AFH Solution for WPAN KC Chen,YC Maa, HK Chen, and Shawn Liu Integrated Programmable Communications, Inc.

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November, 2001 doc.: IEEE /501r0 Submission Slide 3 YC Maa et al., InProComm, Inc. Outline Review on Channel Naming Considerations Regulation Change Effect Implementation and Complexity Conclusion and Recommendation Appendix: Complexity Estimation for AFH

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 4 YC Maa et al., InProComm, Inc. Review on Channel Naming

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 5 YC Maa et al., InProComm, Inc. Channels are classified into 3 groups: (dynamic classification) Usable channel set S U : uninterfered or good channels (size = N U ) Kept channel set S K : interfered channels kept for AFH (size = N K ) Removed channel set S R : interfered channels left out in AFH (size = N R ) N U + N K + N R = 79 Define N min to be the minimum number of channels that a Bluetooth device must hop over. Usable and Kept need to be considered, based on N min, N U : N min N U : only use usable channels in the hopping sequence N min > N U : require kept channels in addition to usable channels in the new hopping sequence, where kept channels N K = N min –N U When kept channels are required, both partition sequence and mapping mechanisms are executed. Mode L uses usable and fill-in channels blindly When kept channels are not required, only mapping mechanism is executed. Review of AFH Channel Naming

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 6 YC Maa et al., InProComm, Inc. Considerations

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 7 YC Maa et al., InProComm, Inc. Worldwide Regulations United States (FCC): Currently FH devices must hop over a minimum of 75 channels. NPRM suggests a new minimum hopset of 15 channels. Two other proposed rule changes on the same NPRM –DSSS processing gain –new Digital Transmission Technologies (DTS) Decision for ruling may drag on Europe (ETSI): FH devices must hop over a minimum of 20 channels, France allows operation at GHz, a total of 37MHz, but Bluetooth devices only use 23 channels. Spain recently increased to a total of 79 channels Japan: No restriction on the minimum number of channels today. Asia (especially China) Rule change usually falls behind US or Europe by 2+ years.

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 8 YC Maa et al., InProComm, Inc. Mode H & L under FCC/Global Regulation Mode H works under current FCC regulation Works for all Bluetooth devices (type 1, 2, 3) today Will always work under FCC regulation, regardless what N min may be. Mode L may not always work under current FCC Does not work for type 1 & 2 Bluetooth devices (high power) May work only for type 3 device (low power constraints) May work better under future FCC regulation (if N min = 15) Mode H always complies with current and future FCC/global regulation, while mode L does not As the ISM band gets more crowded, the benefit of Mode H is more significant.

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 9 YC Maa et al., InProComm, Inc. Important Usage Scenarios: Three b APs (01/443r0) Agreed by all, including TI and Bandspeed, as very important scenario in Mar01 meeting. Three collocated access points (on channel 1, 6, 11) will be common in the enterprise environment. The three networks will occupy a total (30-dB) bandwidth of 66 MHz, which implies that these networks occupy 67 Bluetooth channels. only 12 Bluetooth channels are free of interference (N U = 12). if N min = 15, then we are forced to use 3 kept channels in the adapted hopping sequence. if N min = 20 then we are forced to use 8 kept channels in the adapted hopping sequence. Kept channels must be used intelligently, otherwise - Higher packet error rate, which leads to unacceptable voice quality Lower throughput.

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 10 YC Maa et al., InProComm, Inc. Effects of the NPRM (01/443r0) Proposed rules in NPRM are less strict than the current rules. NPRM was issued to allow new modulation schemes, such as PBCC-22 and OFDM, into the 2.4 GHz band. An OFDM signal has a larger bandwidth than the current IEEE b signals. Spectral mask 20dB-Bandwidth: 22MHz Spectral mask 28dB-Bandwidth: 40MHz Thus, spectrum free of interference will become even more difficult to find!

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 11 YC Maa et al., InProComm, Inc. Regulation Change Effect New NPRM seems to justify Mode L. Yet new application scenarios, enabled by NPRM - Booming enterprise WLAN deployments New technologies, such as OFDM, PBCC-22 will lead to a more crowded ISM band spectrum, which will not leave enough Usable channels for Mode L or FH schemes with small hopset! Mode H is significantly more effective in a more crowded ISM band.

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 12 YC Maa et al., InProComm, Inc. Implementation and Complexity Implementation One shot design vs. Incremental redesign One-shot design –Design right at the first time –Works under any regulation Incremental redesign –Occurs as regulation changes –Overwhelming effort and complexity at a great cost Complexity Relative complexity In % gates to a typical implementation In % MIPS to a typical C processing power Much cheaper than the incremental redesign cost!!

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 13 YC Maa et al., InProComm, Inc. Complexity Estimates for mode H & L (01/471r0) Examined: Mapping & Partition functions Software and hardware realizations Left out: Channel classification algorithm Pseudo-random number generator Assumption: The basic time unit for AFH mechanisms is one slot – 625 us.

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 14 YC Maa et al., InProComm, Inc. AFH Complexity Estimation Summary Hardware complexity mode H - 5.1K gates mode L - 3.1K gates Difference of 2k gates, or 2% for a typical 100K-gate Bluetooth design, or 0.4% for a typical 500K-gate co-located Bluetooth/WLAN design Software complexity mode H ~0.64 MIPS mode L MIPS up to 1.18% more, based on a 40-MIPS micro-controller The added complexities are miniscule Compared to todays HW & SW design overall complexity Compared to the overwhelming incremental-redesign costs For details, please refer to Appendix

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 15 YC Maa et al., InProComm, Inc. Conclusion & Recommendation

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 16 YC Maa et al., InProComm, Inc. Conclusion and Recommendation (1) NPRM leads to more crowded ISM band use Booming enterprise WLAN deployments & new technologies, such as OFDM, PBCC-22 Insufficient usable channels for mode L Mode H not only conforms to current and future FCC regulation, but also adapts to future ISM band wireless boom. Only < 2% complexity added by Partition Sequence, a universal design spares a lot of re-design/re-spin cost and efforts. works all over the world.

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 17 YC Maa et al., InProComm, Inc. Conclusion and Recommendation (2) AFH merger proposal (01/382r0) and AFH draft (01/491r0)- Wise AFH Solution for WPAN Technically, intelligent AFH Scheme Product-wise, deal with current and future market needs while avoiding re-design cost Industry-wise, a wise decision to harmonize AFH schemes in TG2 and Bluetooth SIG Coexistence WG

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 18 YC Maa et al., InProComm, Inc. Appendix : Complexity Estimation for AFH

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 19 YC Maa et al., InProComm, Inc. Appendix: Complexity Estimation for AFH Examined: Mapping & Partition functions Software and hardware realizations Left out: Channel classification algorithm Pseudo-random number generator Assumption: The basic time unit for AFH mechanisms is one slot – 625 us.

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 20 YC Maa et al., InProComm, Inc. Software Implementation Assumption(1) Division/Mod operation A=B*Q+R, Q=floor(A/B), R = A mod B It can be implemented in software by long-division. Each iteration requires 8 operations: –Two shift operations –One compare –One conditional jump –One subtraction, and one addition –Two instructions for loop: one subtraction, and one conditional jump Number of iterations required is equal to the width ( number of bits) of A, W A. The total instruction cycles required is roughly 8* W A.

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 21 YC Maa et al., InProComm, Inc. Software Implementation Assumption(2) Multiplication Many processors have special instruction for multiplication (C=A*B). If not, it can be implemented in software Each iteration requires 5 operations: –Two shift operation –One conditional addition –Two instructions for loop: one subtraction, and one conditional jump Number of iterations required is equal to min{W A,W B } The total instruction cycles required is roughly 5*(min{W A,W B })

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 22 YC Maa et al., InProComm, Inc. Software Implementation: Mode L Mapping Instructions Mod operation x 1: Assume 12-bits pseudo-random signal, thus 12-bit mod operation 96 instruction cycles Misc. instructions Add/if-then-else/table-lookup/load-store variables 10 instruction cycles Totally 106 instruction cycles Load 106/625us = MIPS

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 23 YC Maa et al., InProComm, Inc. Software Implementation : Mode H Partition Sequence-SCO (1) For the first MAU (master-slave pair) Distribution unit: Variables initial calculations Six div/mod operations –27bits x 1, 9bits x 1, 8bits x 1, 7bits x 3 –8*( *3)= 520 instruction cycles Two multiplications –2bits x 2 –2*5*2=20 instructions cycles Misc instructions(logic/compare/jump/add-sub/load) –30 instruction cycles Arrangement unit: if-then-else/table-lookup –10 instruction cycles Totally 580 instruction cycles

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 24 YC Maa et al., InProComm, Inc. Software Implementation : Mode H Partition Sequence-SCO (2) For the remaining MAUs within one superframe Distribution unit: Variables update 25 instructions cycles Arrangement unit: if-then-else/table-lookup 10 instruction cycles Totally 35 instruction cycles For MAUs after one superframe The partition sequence is periodic with superframe The maximum length of superframe is 3*79 MAUs Require 237 bits (about 30 bytes) to store one period Table-lookup/index update: 10 instructions

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 25 YC Maa et al., InProComm, Inc. Software Implementation: Mode H Mapping Instructions Mod operation x 1: Assume 12-bits pseudo-random signal, thus 12-bit mod operation 96 instruction cycles Misc instructions Add/if-then-else/table-lookup/load-store variables 15 instruction cycles Totally 111 instruction cycles Load 111/625us = MIPS

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 26 YC Maa et al., InProComm, Inc. Software Implementation: Mode H The complexity of mode H is the sum of mapping and partition sequence Note that partition sequence is not calculated every slot, but every MAU (two slots) For the first MAU: MIPS + 580/(625us*2) = MIPS For the remaining MAUs within one superframe MIPS + 35/(625us*2) = MIPS After one superframe MIPS + 10/(625us*2) = MIPS

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 27 YC Maa et al., InProComm, Inc. Hardware Implementation Assumption(1) Unit of gate count: NAND gate. Use one hardware block for multiple occurrences of the same operation. Ex: there may be several mod operations, but only one div/mod hardware is needed. Variable storage/mapping table: 4 gates per bits. Division/Mod operation A=B*Q+R, Q=floor(A/B), R = A mod B It can be implemented in hardware by long-division: Multiple clock implementation, shift-in one bit of operand A at each clock. Require W A clocks to finish one operation. Gate count required is in proportional to W B.

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 28 YC Maa et al., InProComm, Inc. Hardware Implementation: Mode L Mapping Hardware blocks: Adder 12-bits Gate count = 0.1K Mod W B =7 Gate count = 1K Mapping table 79*7 bits Gate count = 2K Total gate count = 3.1K

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 29 YC Maa et al., InProComm, Inc. Hardware Implementation: Mode H Mapping Hardware blocks: Adder 12-bits Gate count = 0.1K Mod W B =7 Gate count = 1K Mapping table 79*7 bits Gate count = 2K Misc 0.2 K Total gate count = 3.3K

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 30 YC Maa et al., InProComm, Inc. Hardware Implementation: Mode H Partition Sequence Hardware blocks: Multiplier: 8bit x 8 bit, parallel multiplier Gate count = 0.5K Division/Mod W B =8 Gate count = 1K Add/Sub Gate count = 0.1K Variable storage and procedure control Gate count = 1K Misc Gate count = 0.2K Total gate count = 2.8 K

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 31 YC Maa et al., InProComm, Inc. Hardware Implementation: Mode H The complexity of mode H is the sum of mapping and partition sequence Direct summation of the two gate count numbers: 3.3K + 2.8K = 6.1K Note that the mod/division block can be further shared Gate count can be reduced to 5.1K

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Integrated Programmable Communications, Inc. November, 2001 doc.: IEEE /501r0 Submission Slide 32 YC Maa et al., InProComm, Inc. Complexity Considerations with Reference Numbers for Bluetooth The hardware implementation of LC is about 70K-100K gates The computation power required for LMP, L2CAP, and HCI is about 10 ~ 20 MIPs, while typical processors can easily provide up to 40 MIPs. The complexity added, in software or hardware, is miniscule!

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