05-04-2012, 02:01 PM
Antenna Selection Algorithm for MIMO Broadcast Channel
Antenna Selection Algorithm for MIMO Broadcast Channel.doc (Size: 552.5 KB / Downloads: 43)
INTRODUCTION
Multiple-Input Multiple-Output (MIMO) is one of the important communication techniques that allow wireless systems to achieve higher data rate [1] – [3]. Another benefit of MIMO is the use of spatial diversity which can be used to provide more reliable communication [4]. MIMO can achieve maximum spatial diversity gain by using Space-time Block coding (STBC)[5].One key benefit of using MIMO is the resultant high spatial multiplexing gain which can be obtained by sending independent message streams over any transmit- receive antenna pair simultaneously. The very well known DPC (Dirty Paper Coding) has established the idea that wireless systems can achieve data rate very close to the fundamental capacity limit of the system by serving multiple users simultaneously. In multi-user MIMO systems which have many users at the receiver side,
SYSTEM MODEL
The wireless MIMO system that is considered here has M transmit antennas at the base station and N number of users with each users having K number of receive antennas as shown in Fig. 1. So there are K x N number of receive antennas in all from which the base station selects M for communication. The received signal by the nth user at any timeslot is
SIMUALTIONS AND RESULTS
In this section we present the simulation results for the throughput analysis for the proposed scheduling algorithm according to (4). The simulation is performed for M=2 and K=2 over 10000 iterations. In Fig.2, the simulation result for the achievable throughput versus number of users is shown for 0, 5 and 10 dB SNR respectively.
CONCLUSIONS
We have investigated various multiuser antenna selection algorithms for MIMO broadcast channel. Our approach differs from the other antenna selection in that both the users as well as the antenna selection are done at the transmitter side whereas in other antenna selection algorithms the antenna selection is done at the user side. The total throughput achieved by our approach is more than the other antenna selection approach at the slight cost of feedback load. It is also seen in the modified approach that the feedback load is greatly reduced, by implementing a selection based on a threshold value of SINR, with an insignificant loss in the total throughput. All the discussed antenna selection algorithms assume the channel to be IID. For future work the antenna selection algorithm approach can be implemented for non-IID channels.