Abstract
The adoption of multiple antennas both at the transmitter and the receiver will explore additional spatial resources to provide substantial gain in system throughput with the spatial division multiple access (SDMA) technique. Optimal multiuser MIMO linear precoding is considered as a key issue in the area of multiuser MIMO research. The challenge in such multiuser system is designing the precoding vector to maximize the system capacity. An optimal multiuser MIMO linear precoding scheme with LMMSE detection based on particle swarm optimization is proposed in this paper. The proposed scheme aims to maximize the system capacity of multiuser MIMO system with linear precoding and linear detection. This paper explores a simplified function to solve the optimal problem. With the adoption of particle swarm optimization algorithm, the optimal linear precoding vector could be easily searched according to the simplified function. The proposed scheme provides significant performance improvement comparing to the multiuser MIMO linear precoding scheme based on channel block diagonalization method.
Highlights
In recent years, with the increasing demand of transmitting high data rates, the (Multiple-Input Multiple-Output) MIMO technique, a potential method to achieve high capacity has attracted enormous interest [1, 2]
When multiple antennas are equipped at both base stations (BSs) and mobile stations (MSs), the space dimension can be exploited for scheduling multi-user transmission besides time and frequency dimension
It has been shown that time division multiple access (TDMA) systems can not achieve sum rate capacity of MUMIMO system of broadcast channel (BC) [5] while MUMIMO with spatial division multiple access (SDMA) could, where one BS communicates with several MSs within the same time slot and the same frequency band [6, 7]
Summary
With the increasing demand of transmitting high data rates, the (Multiple-Input Multiple-Output) MIMO technique, a potential method to achieve high capacity has attracted enormous interest [1, 2]. When multiple antennas are equipped at both base stations (BSs) and mobile stations (MSs), the space dimension can be exploited for scheduling multi-user transmission besides time and frequency dimension. MUMIMO based on SDMA improves system capacity taking advantage of multi-user diversity and precanceling of multiuser interference at the transmitter. Traditional MIMO technique focuses on point-to-point transmission as the STBC technique based on space-time coding and the VBLAST technique based on spatial multiplexing. The former one can efficiently combat channel fading while its spectral efficiency is low [8, 9]. When the MU-MIMO technique is adopted, both the multiuser diversity gain to improve the BER performance and the spatial multiplexing gain to increase the system capacity will be obtained. It is essential to have CSI at the BS since it allows joint processing of all users’ signals which results in a significant performance improvement and increased data rates
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