BW REQ preamble Document Number IEEE C 802
BW REQ preamble Document Number: IEEE C 802. 16 m-09/1452 Date Submitted: 2009 -07 -06 Source: Jinyoung Chun, Bin-Chul Ihm, Youngsoo Yuk, Heejeoung Cho LG Electronics Re: Email: {jychun 03} @lge. com Category: AWD comments / Area: Chapter 15. 3. 9 (UL-CTRL) “Comments on AWD 15. 3. 9 UL-CTRL” Venue: IEEE Session #62 Purpose: To be discussed and adopted in the Amendment Working Document 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/sect 6 -7. html#6> and <http: //standards. ieee. org/guides/opman/sect 6. html#6. 3>. Further information located at <http: //standards. ieee. org/board/pat-material. html> and <http: //standards. ieee. org/board/pat >.
BW REQ channel in AWD n The procedure ü n The BW REQ channel structure ü ü n In the LZone with PUSC, a BW REQ tile is defined as four contiguous subcarriers by six OFDM symbols. The number of BW REQ tiles per BW REQ channel is three or six. Each BW REQ tile carries a BW REQ access sequence only. In the Mzone, a BW REQ tile is defined as six contiguous subcarriers by six OFDM symbols. Each BW REQ channel consists of three distributed BW-REQ tiles. Each BW REQ tile carries a BW REQ access sequence and a BW REQ message. The AMS may transmit the access sequence only and leave the resources for the quick access message unused. The BR REQ preamble part ü ü ü n There are two kinds of BR procedure: 5 -step regular procedure and 3 -step quick access procedure. 16 bits of information to be carried as the quick access message. A 5 -step regular procedure or an optional 3 -step quick access procedure may be supported concurrently. The 5 -step regular procedure is used independently or as a fallback mode for the 3 -step bandwidth request quick access procedure. Total 72 subcarriers (24 subcarrier per tile). BWREQ_PREAMBLE_INDEX is randomly selected in the Lzone with PUSC. 4 bits of the 16 information bits shall be carried in the BW REQ preamble part using the preamble index in the Mzone. The sequence and number of the preamble are TBD. The BW REQ message part ü ü Total 36 subcarriers (12 subcarrier per a tile). 12 bits are carried in the BW REQ message part using the 1/6 TBCC code. 2
BR preamble issues n 3/5 -step code partition ü n MS can transmits BR preamble with or without BR message. That is, BS received BRCHs which some of them has BR message and some of them hasn’t BR message. Therefore we need to distinguish between the preamble with message and the preamble without message. The number of preamble code ü To support two sets of the preamble, the number of preamble code is more than 16. But the extension of the number cause the performance degradation.
3/5 -step code partition n The problem without code partition ü n Degradation of the message detection performance. Because BS performs MMSE with the number of detected preamble codes. Simulation result 1 ü BR message detection performance n 1. 2. Code partition between preamble only and preamble + message. When BS know the number of message (code partition) When BS don’t know the number of message (no code partition) Simulation environment # Antenna 1 Tx, 4 Rx Channel Ped. B 3 km/h # tx users 4 users - 4 preambles - 1/2/4 messages Preamble detection Non-coherent detection (ML) Message detection MRC for 1 user if BS knows MMSE for others A case with code partition has about 1 d. B gain than a case without code partition.
3/5 -step code partition n The problem without code partition ü n After MMSE with the number of detected preamble codes, BS select some messages with signal power threshold, etc. What is exact threshold value? Simulation result 2 ü The signal power after MMSE. n n The range is the operation point. (1% ~0. 1% PER for preamble, 10%~1% PER for message) The value is the normalized value of signal power to noise and interference power. Tx SNR (d. B) The signal power of message part with message The signal power of message part without message (No signal) -8 0. 04 0. 03 -6 0. 09 0. 07 -4 0. 27 0. 18 -2 0. 38 0. 22 0 0. 46 0. 22 The table is shown that it’s difficult to choose a fixed threshold value to detect the message. It causes to increase message missing probability and false alarm probability.
The number of preamble code n The number of preamble code 1. 2. 3. n 24: orthogonal hadamard code of length 24, BPSK 32: punctured orthogonal hadamard code of length 36, BPSK 48: orthogonal hadamard code of length 48, QPSK Simulation result 3 ü The performance according to the number of code Simulation environment # Antenna 1 Tx, 4 Rx Channel Ped. B 3 km/h Preamble detection Non-coherent detection (ML) 32 codes has 0. 5 d. B loss than 24 codes. And 48 codes has 1 d. B loss than 24 codes.
Conclusion n n 3/5 -step code partition is needed. The number of preamble is over 32 to support code partition. ü ü For 3 -step code partition, 16 codes are supported. For 5 -step code partition, over 16 codes are supported. Adopt the proposed text in C 80216 m-09/1453.
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