Linan Sun

Base station cooperation based on location-aided in cellular system

Base station cooperation will bring a certain delay due to a series of signaling information exchange, cooperation strategy on base station based on location-aided is proposed in this paper. Future location information is provided by moving speed and direction to predict track of user. Signal strength and adjacent cell load combining with location information will be constraints to selecting cooperative base station. User can execute signaling interaction in advance with network before signal strength down to an intolerable to reduce delay to increase satisfaction of users. Meanwhile, Quality of signal in edge of cell is improved due to base station cooperation and handover requests decrease in the process of user mobility. Then unnecessary handover is avoided. Comparing with no location-aided, pseudo cooperative request and cooperative setting updating will be reduced. It was shown that base station cooperation based on location-aided we provided can reduce system overhead and increase system capacity.

Capacity analysis of downlink MRT-SC in distributed antenna system

This paper investigates the downlink capacity of maximal ratio transmission-selection combining (MRT-SC) in the distributed antenna system (DAS). Composite fading channels are assumed, which include path loss, lognormal shadowing and multi-path Rayleigh fading. Analytical approximation of the capacitys cumulative distribution function (CDF) is derived by means of a moment generation function (MGF) based approach. The influence of transmit/receive antenna number on the capacity distribution and the impact of receiver location on the 10% outage capacity are investigated. Simulation results agree with the analytical approximations well. Furthermore, it shows that the 10% outage capacity of MRT-SC presents an approximately uniform distribution over most of the interested area, and its value is almost the same with maximal ratio transmission-maximal ratio combining (MRT-MRC).

Implementation of coded cooperation using a kind of convolutional codes

User cooperative communication can bring spatial diversity, and improve cell boundary uplink quality. This paper gives a kind of convolutional codes suitable for user cooperation with lower complexity than Turbo codes and LDPC codes, and can guarantee good inter-user communication quality when cooperation succeeds, and also good uplink communication quality when cooperation defeats. Simulation results show that when we use 50% cooperation, under the condition that the two users have similar uplink quality and perfect inter-user channel, at BER=10−3, this kind of coded cooperation can provide almost 11 dB performance gains, compared with non-cooperation. Moreover, performance of user cooperation using this kind of convolutional codes is better than that using rate-compatible punctured convolutional codes.