1. Page 1 C30-20070108-60 ----------------------------------------------------------------------------------------------------------------- Title: Traffic activity based RPC for OFDM data channel ----------------------------------------------------------------------------------------------------------------- Abstract ： In this contribution, we propose additional process of OSI bit in the procedure of AT power spectral density (PSD) control for reverse OFDM traffic channel to improve the reliability of OSI bit and avoid error change of PSD that causes performance degradation. ----------------------------------------------------------------------------------------------------------------- Source: ZTE Corporation Yuanli Fang Fang.yuanli@zte.com.cn Yu Xin Xin.yu@zte.com.cn ----------------------------------------------------------------------------------------------------------------- Data: January 6,2007 ----------------------------------------------------------------------------------------------------------------- Recommendation ：Fang.yuanli@zte.com.cn TSG-WG3 -------------------------------------------------------------------------------------------------------------------------------------------------------- The contributors grant a free, irrevocable license to 3GPP2 and its Organizational Partners to incorporate text or other copyrightable material contained in the contribution and any modifications thereof in the creation of 3GPP2 publications; to copyright and sell in Organizational Partner's name any Organizational Partner's standards publication even though it may include all or portions of this contribution; and at the Organizational Partner's sole discretion to permit others to reproduce in whole or in part such contribution or the resulting Organizational Partner's standards publication. The contributors are also willing to grant licenses under such contributor copyrights to third parties on reasonable, non-discriminatory terms and conditions for purpose of practicing an Organizational Partner’s standard which incorporates this contribution. This document has been prepared by the contributors to assist the development of specifications by 3GPP2. It is proposed to the Committee as a basis for discussion and is not to be construed as a binding proposal on the contributors. The contributors specifically reserve the right to amend or modify the material contained herein and nothing herein shall be construed as conferring or offering licenses or rights with respect to any intellectual property of the contributors other than provided in the copyright statement above.

2. Page 2 C30-20070108-60 Introduction  Power control for OFDM traffic channel (R-DCH) was described in LBC framework (C30-20060731-040R4).  It is power spectral density (PSD) based power control according to the other sector interference (OSI), include F-OSICH( update per super frame ) and F-FOSICH ( update per phy frame ). When OSI values received from nearby sectors indicate ‘0’ (unloaded), AT tries to increase its PSD for R-DCH. When OSI values received from nearby sectors indicate ‘1’ (loaded) or ‘2’ (fully loaded), AT tries to decrease its PSD for R-DCH.  Every sector controls its IoT through OSI-based PSD control :

3. Page 3 C30-20070108-60 Introduction (Cont ’ d) At the transmitter, F-OSICH carries a three-state quantity that is modulated as a phase on TDM pilots 2 and 3 and has no error correction. Due to the complicate wireless environment, the OSI bit AT demodulate may exists misdetection and false alarm. when AT receive these error OSI bit, according to the OSI-based RPC algorithm, the PSD △ P may change at wrong direction, thus leads to high IoT for other sectors and performance degradation.

4. Page 4 C30-20070108-60 PSD Control Using filtered OSI Bit To avoid the situation described in the previous slides, we propose additional filtering processing of OSI bits at AT PSD control algorithm. The procedure is following:  AP set filter time constant to AT through air interface messages, this step can be omitted if AT use fixed time constant;  AT demodulate the F-OSICH&F-FOSICH and get soft OSI bit information;  AT shall generate filtered OSI by filtering soft OSI bits use a FIR type or IIR type filter.  AT use a threshold detector to hard limiting filtered OSI and generate the instantaneous OSI bit (value is ‘0’,’1’,’2’ );  AT use instantaneous OSI bit as the input of RPC algorithm to adjust output power. The demo IIR filter equation is : y(n) = ( 1 – a )*y(n-1) + (1/a)*y(n) a is the time constant, this parameter can be fixed at AT or received from AP.

5. Page 5 C30-20070108-60 The advantage of using filtered OSI Bit  It can improve the reliability of the OSI bits receive by AT and easy to implement;  AT can maintain a stable and smooth PSD control;  It can avoid big fluctuation of AT traffic;