doc.: IEEE /1387 r0 Submission November 2014 Packet Encoding Solution for 45GHz Date: Authors: NameAffiliationsAddressPhone Liguang LiZTE CorporationShenzhen Jun XuZTE CorporationShenzhen Zhifeng YuanZTE CorporationShenzhen Bo SunZTE Ke YaoZTE Kaibo TianZTE Shiwen HeSoutheast University (SEU) Nanjing Haiming Wang Southeast University (SEU) Nanjing Slide 1 Liguang Li(ZTE Corp.)

doc.: IEEE /1387 r0 Submission November 2014 Traditional data packet processing: – Code Block Segmentation -> FEC Encoding -> Data Y (transmit). Slide 2 Liguang Li(ZTE Corp.) Background: Traditional Packet

doc.: IEEE /1387 r0 Submission November 2014 The longer a data packet is, the worse PER it will get –The PER(Packet Error Rate) of traditional data packet: PER=1-(1-BCER)^a ≈ a × BCER, where a is the number of FEC code blocks, BCER denotes Block Code Error Rate of FEC A simple and effective solution is necessary to improve reliability of data packet in aj. –802.11aj is used for ultra high speed data and video transmission. Therefore, wide range of data octets of the PSDU will cause quite a lot of FEC code blocks. Slide 3 Liguang Li(ZTE Corp.) Background: Traditional Packet

doc.: IEEE /1387 r0 Submission November 2014 Procedure: Code block segmentation -> Adding CRC -> LDPC Encoding -> Packet Encoding -> Bits Selection -> Data Y (transmit). Slide 4 Liguang Li(ZTE Corp.) Proposed: Packet Encoding Solution

doc.: IEEE /1387 r0 Submission November 2014 Encoding Process: –Adding CRC: Divide the source data into a groups of k bits, where k=328 for code rate 1/2, k=412 for code rate 5/8, k=496 for code rate 3/4, k=538 for code rate 13/16. Adding 8 bits CRC sequence to each group. Then all groups are encoded to create LDPC code blocks (C 0,C 1,C 2,…, C a-1 ) with length of 672 bits. –Packet Encoding: parity packet is created by:, where the symbol is XOR. The length of parity packet is 672 bits. Slide 5 Liguang Li(ZTE Corp.) Details of the Proposed Solution

doc.: IEEE /1387 r0 Submission November 2014 Encoding Process: –Bits Selection: the punctured bits number (ei, i=0 、 1 、 … 、 a-1) of a LDPC code blocks are set by: 1 、 if 1<a<=15: 2 、 if a>15: Where, 3 、 if a==1: e0=0 ； The punctured bits number (ei,i=a) of parity packet is set by: Where, n is the size of LDPC code and n=672. Slide 6 Liguang Li(ZTE Corp.) Details of the Proposed Solution

doc.: IEEE /1387 r0 Submission November 2014 Encoding Process: –Data Y is generated by: Slide 7 Liguang Li(ZTE Corp.) Details of the Proposed Solution

doc.: IEEE /1387 r0 Submission November LDPC code blocks LDPC code blocks Examples: Slide 8 Liguang Li(ZTE Corp.) Proposed: Packet Encoding Solution

doc.: IEEE /1387 r0 Submission November 2014 Simulation parameters: –Channel: AWGN. –Modulation Mode: QPSK, 16QAM, 64QAM. –Code Rate: 1/2, 5/8, 3/4, 13/16. –The number of LDPC code blocks in a data packet: 10, 20, 50,100. Performance Comparison: –Compensation of 8 CRC bits for traditional packet:, where k is the information bits length of LDPC code. The value of k is 328 for code rate 1/2, 412 for 5/8, 496 for 3/4 and 538 for 13/16. Slide 9 Liguang Li(ZTE Corp.) Simulation

doc.: IEEE /1387 r0 Submission November 2014 Performance(QPSK, AWGN): –Rate of 13/16, gain(PER=0.1): 10 LDPC: 0.2dB ； 50 LDPC: 0.6dB ； 100 LDPC: 0.8dB 。 –Rate of 1/2, gain (PER=0.1): 10 LDPC: 0.1dB ； 50 LDPC: 0.3dB ； 100 LDPC: 0.3dB 。 Slide 10 Liguang Li(ZTE Corp.) Simulation

doc.: IEEE /1387 r0 Submission November 2014 Performance(16QAM, 64QAM, AWGN): –20 LDPC ， 64QAM ， gain(PER=0.1): Rate of 5/8: 0.3dB ； Rate of 3/4: 0.3dB ； Rate of 13/16: 0.6dB. –20 LDPC, 16QAM ， gain(PER=0.1): Rate of 1/2: 0.3dB; Rate of 3/4: 0.2dB. Slide 11 Liguang Li(ZTE Corp.) Simulation

doc.: IEEE /1387 r0 Submission November 2014 Transmitter –1. cumulative XOR module (parallel or serial) for packet encoding. 2. buffer (size of 672 bits) for results of XOR. Receiver –1. Buffers for LLR of LDPCs decoded failure and result of cumulative XOR of LDPCs decoded correctly. 2. Decoder of XOR(min-sum, parallel or serial). Conclusion: Low complexity Slide 12 Liguang Li(ZTE Corp.) Complexity Analysis

doc.: IEEE /1387 r0 Submission November 2014 Why does it work? –According to Information Theory, for any single FEC (Forward Error Correction) code, the longer it is, the better performance it will get. –LDPC can not support any code length and the length can not be very long due to complexity. –Usually, the large traditional data packet is divided into small FEC code blocks, the PER of the whole data packet can be proximately equal to BCER*a. Where a is the number of FEC code blocks. BCER is a relatively constant value for a certain setting. So the longer of the large data packet is, the worse PER it will get using traditional processing. –The proposed solution builds relationship among all the code blocks, so that we will get a gain similar to that of a large data packet using LDPC encoding. –Of course the operation we introduced is XOR instead of the complex LDPC, so the gain will not be so large as LDPC. And in order to reach the same rate as traditional data packet processing we puncture some bits which will affect the gain. These effects can hardly be derived algebraically, therefore simulation is an effective way to measure it. Slide 13 Liguang Li(ZTE Corp.) Effectiveness Analysis

doc.: IEEE /1387 r0 Submission November 2014 We proposed a packet encoding solution for group discussion. The simulation results show that the packet encoding solution brings a good gain compared to the traditional method with adding low complexity for both transmitter and receiver. Slide 14 Liguang Li(ZTE Corp.) Summary