Antenna Selection in Space-Time Block Coded Systems: Performance Analysis and Low-Complexity Algorithm

Abstract

This paper presents outage probability analysis and a practical algorithm for antenna selection in multiple-input multiple-output wireless communication systems employing space-time block codes (STBC). First, to minimize the outage probability in these systems, a satisfactory antenna selection criterion for an STBC is to maximize the channel Frobenius norm. Analysis shows that the more receive antennas are selected, the better the performance. However, the performance of transmit antenna selection heavily depends on how fast the channel changes. When the channel changes slowly, since STBC averages the channel gains of the selected transmit antennas, selecting more transmit antennas causes lower coding gain and thus higher outage probability. When the channel is fast changing, it is shown analytically that the system can no longer provide transmit selection diversity in the high SNR regime. Since the transmit diversity can be still provided by using STBC, the best STBC scheme varies with SNR. Although the outage analysis helps determine the STBC scheme, finding the optimal antenna subsets with maximum channel Frobenius norm for each fading state is still a challenging problem. This is because solving the problem optimally requires an exhaustive search with exponentially growing complexity. When the numbers of antennas are large, the problem becomes intractable. To reduce the complexity, this problem is formulated as a quadratically constrained quadratic programming (QCQP) problem. Despite the fact that the problem is nonconvex, a semidefinite relaxation of QCQP enables the problem to be solved approximately in polynomial time. Simulation results indicate that the loss of semidefinite relaxation to optimal selection is negligible.Index Terms-Antenna selection, multiple-input-multipleoutput (MIMO), outage analysis, space-time block codes (STBC).

Energy Efficiency of Transmit Diversity Systems Under a Realistic Power Consumption Model

“…, and after replacing E T BF , P ⋆ T BF , and γ by (10), (9) and (2), we can determine a sufficient distance d T BF,T BF (M ′ , M ′′ ) from which using M ′′ transmit antennas is more energy efficient than using M ′ antennas (M ′′ > M ′ ), as shown in (11). Thus, using more transmit antennas is not always a more energy efficient solution in TBF.…”

Capacity of Orthogonalized Weibull MIMO Channels Under Different Adaptive Transmission Techniques

“…It is assumed that the rate of STBC is R and the average transmitted power is S. The effective signal to noise (SNR) at the output of the STBC decoder, denoted by γ , can be expressed as [4] …”

“…Orthogonal space time block codes (STBCs) are an open-loop transmit diversity scheme that decouple the MIMO channel, thereby reducing the space time decoding into a scalar detection process [2,3]. The technology of STBCs can set off fading effectively and increases frequency spectrum efficiency [4].…”

Performance analysis of OFDM system with transmit antenna selection using delayed feedback

“…Performance analysis of MIMO systems with antenna selection is well documented in literature, a few of them are [10,11]. However, most of them have considered flat fading channels.…”