AT TOP	Paper 1428	US-T-P	DOWN
SIR prediction for downlink packet access.
Ling,Jonathan		Lucent, Bell Labs
Tureli,Uf		Stevens Institute of Technology
Abstract: In cellular networks signals from basestations interfere with each other on downlink. In such systems with frequency reuse equal to one, typically more than forty percent of the cell area faces an signal to interference ratio of 0 dB or less. To improve system throughput, packet transmissions to mobiles are scheduled by the base when signal to interference ratio is higher than its own average. A frequency duplex system is assumed where the mobile measures the downlink pilots from the serving base station and an interfering basestation, and feeds back the SIR as a measure of the achievable rate. We examine the prediction of the channel and signal to interference ratio by the mobile. Both powers are modeled as auto-regressive (AR) stochastic processes. We derive the probability distribution function of the prediction error to determine the backoff margin required for a percentage of packets to be decoded successfully. The performance improvement due to prediction for a proportional fair scheduled system is shown through simulation.
Jonathan joined the Wireless Communications Research Department of Bell Laboratories, Holmdel, NJ in 1994. He has contributed to radio propagation measurements and modeling for cellular as well as for DARPA MNM project. His interests are channel prediction, and link and network level modeling and performance of wireless systems. He is currently pursing a Ph.D. in electrical engineering at Stevens.