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Tail-Biting Convolutional Codes for the Secondary Fast Feedback Channel: Fading Channel Results
Document Number: C802.16m-09/0910 Date Submitted: 2009-04-27
Source: Ericsson AB, Tsao-Tsen (Jason) Chen ([email protected]) Kai Yu
Sten SjöbergPer-Erik Östling
Re: Category: AWD comments / Area: Chapter 15.3.9 (UL-CTRL) “Comments on AWD 15.3.9 UL-CTRL” Venue:
Base Contribution:Purpose: To be discussed and adopted by TGm for the 802.16m AWD.Notice:
This document does not represent the agreed views of the IEEE 802.16 Working Group or any of its subgroups. It represents only the views of the participants listed in the “Source(s)” field above. It is offered as a basis for discussion. It is not binding on the contributor(s), who 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 802.16.
Patent Policy:The contributor is familiar with the IEEE-SA Patent Policy and Procedures:
<http://standards.ieee.org/guides/bylaws/sect6-7.html#6> and <http://standards.ieee.org/guides/opman/sect6.html#6.3>.Further information is located at <http://standards.ieee.org/board/pat/pat-material.html> and <http://standards.ieee.org/board/pat >.
Tail-biting convolutional codes (TBCC) for Secondary Fast Feedback Channel (SFBCH)
• Performances of TBCC [1] over fading channels are better than or about the same as other linear block codes [2] for SFBCH for payload 7 to 24 bits– 13 to 24 bits: 0.4dB~2.3dB gain @ PER=10-1 ~10-3
– 7 to 12 bits: about the same performances
• TBCC can be decoded efficiently by simple Wrap-Around Viterbi Algorithm (WAVA), with complexity much less than linear codes with MLD or trellis decoding for most payload cases [1]
TBCC w 1 Encoding: one 18-bit payload Linear Code w 2 Encodings: two 9-bit payloads
-6 -4 -2 0 2 4 6 8 10 12 1410
-4
10-3
10-2
10-1
100
EsN0 (dB)
PE
R
payload 18 bits, 1Tx2Rx, VehA 120Km/hr
Intel (30,9)
Samsung (30,9)LGe (30,9)
TBCC (60,18)
TBCC gains over the best of 3 linear codes: payload >12 bits (0.4dB~2.3dB)
ChannelModel
ChannelEstimation
Target PER
Payload 14 bits
Payload 16 bits
Payload 18 bits
Payload 20 bits
Payload 22 bits
Payload 24 bits
PedB-3 pilot avg 10% 0.54 0.54 0.47 0.43 0.42 0.42
VehA-120 pilot avg 10% 0.79 0.70 0.68 0.71 0.69 0.66
VehA-350 Perfect 10% 1.35 1.47 1.31 1.22 1.27 1.18
PedB-3 pilot avg 1% 0.49 0.53 0.50 0.42 0.38 0.43
VehA-120 pilot avg 1% 1.06 1.03 1.04 1.08 1.06 1.12
VehA-350 Perfect 1% 1.83 1.84 1.73 1.67 1.56 1.47
PedB-3 pilot avg 0.1% 0.57 0.45 NA NA NA NA
VehA-120 pilot avg 0.1% 1.66 1.68 1.78 1.96 2.05 2.34
VehA-350 Perfect 0.1% 2.12 2.18 1.99 1.91 1.82 1.76
TBCC losses over the best of 3 linear codes: payload ≤ 12 bits (about the same performances)
ChannelModel
ChannelEstimation
TargetPER
Payload 7 bits
Payload 8 bits
Payload 9 bits
Payload 10 bits
Payload 11 bits
Payload 12 bits
PedB-3 pilot avg 10% 0.09 0.09 0.08 0.06 0.05 0.07
VehA-120 pilot avg 10% 0.08 0.09 0.09 0.06 0.06 0.09
PedB-3 pilot avg 1% 0.07 0.09 0.07 0.04 0.05 0.09
VehA-120 pilot avg 1% 0.07 0.09 0.09 0.05 0.06 0.12
VehA-350 Perfect 1% -0.46 0.18 0.12 0.09 0.08 0.07
PedB-3 pilot avg 0.1% 0.05 0.10 0.08 0.04 0.05 0.12
VehA-120 pilot avg 0.1% 0.09 0.12 0.10 0.06 0.06 0.16
VehA-350 Perfect 0.1% 0.33 0.22 0.13 0.09 0.08 0.07
Conclusion and References
• We recommend that TBCC [1] be used to encode the SFBCH with payload sizes from 7 to 24 bits, with one encoding [1] for all payload cases.
• [1] IEEE C80216m-09_0506r3, “Tail-Biting Convolutional Codes with Expurgation and Rate-Compatible Puncturing for the Secondary Fast Feedback Channel”.
• [2] IEEE C80216m-09_0387, “Proposed Text for the Draft P802.16m Amendment on the PHY structure for UL control – merged version”.
Backup Slides
Simulation Assumptions
Channel Bandwidth 10MHz
FFT Size 1024
Cyclic Prefix Ratio 1/8
Channel Model PedB-3Km/hr, VehA-120Km/hr, VehA-350Km/hr
Antenna Scheme 1Tx2Rx
Modulation QPSK
Channel Estimation Perfect channel estimation and pilot averaging
Tile Structure 3 distributed 2x6 tiles, 2 pilots per tile
Decoder TBCC: Wrap-around Viterbi algorithm with simple termination condition and maximum 4 iterationsLinear codes: MLD
Error Statistics For linear codes with 2 smaller encoded packets per payload (13 bits to 24 bits), the overall packet is declared erroneous if either one of the 2 smaller encoded packets is in error