[Show abstract][Hide abstract] ABSTRACT: This paper investigates optimal transmission of space-time block codes (STBCs) in distributed multiple-input multiple-output (D-MIMO) Rayleigh fading channels. The optimal diversity performance is achieved through transmit power allocation implemented at the receiver based on transmit and receive correlations to minimize the average symbol error rate (SER). Evaluation of SER performance of uncoded STBCs over a generalized distributed antenna (DA) topology is first presented, with exact analytical SER expressions derived for MQAM and MPSK symbols. SER upper bounds are also derived, based on which two criteria for complexity reduced antenna subset selection with sub-optimal power allocation are further proposed, whose performance approaches optimal over correlated D-MIMO channels. Moreover, a novel simplified but close SER approximation scheme is devised to significantly facilitate optimal SER calculation. We continue to thoroughly analyze how the optimal diversity is affected by large scale fading, targeted data rate, antenna correlations and transmit power. Finally, we develop a surprisingly close and useful analogy between open loop STBCs in co-located MIMO and optimal STBCs in D-MIMO with minimum feedback (i.e., n bits for n DAs in Criterion 2 with power allocation scheme 2 which equally allocates power to the selected DAs). Extensive simulation results have been presented to demonstrate the effectiveness of our analysis.
IEEE Transactions on Wireless Communications 07/2008; · 2.42 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: High spectral efficiency distributed antenna systems (DAS) require vertical Bell-Labs layered space-time (V-BLAST) like spatial multiplexing schemes. However, unlike normal point-to-point multiple input multiple output (MIMO) channels, DAS channels have different large-scale fadings from different transmit antennas, thus making equal power and rate transmission that is feasible in MIMO channels unrealistic in DAS channels. This paper proposes a novel transmit antenna selection scheme with power and rate allocation. The scheme is based on large-scale fading (shadow fading and path loss) and is suitable for V-BLAST structures with zero-forcing and successive interference cancellation (ZF-SIC) receivers, ensuring balanced average symbol error rate (SER) performance in each layer. On the receiver side, a fixed detection order is used, which is obtained in the transmit antenna selection process. Simulation results show that the proposed scheme gives good performance gains over equal power and rate transmission systems without antenna selection.
[Show abstract][Hide abstract] ABSTRACT: This paper studies downlink transmits antenna selection with power and rate allocation in generalized distributed wireless communication systems (G-DWCS). Based on the large-scale fading statistics (path loss and shadow fading) at the transmitter, antenna selection criteria have been proposed for combined space time block code (STBC) and Vertical Bell-Labs Layered Space Time (V-BLAST) structure, where each layer of V-BLAST is composed of co-located multiple antennas for independent STBC transmission. The sub-optimal antenna set, sub-optimal power and rate allocation are determined to minimize an upper bound on the symbol error rate (SER). At the receiver a fixed detection order is followed which is obtained meanwhile in the antenna selection process at the transmitter. It's verified by Monte Carlo simulation that our proposed antenna selection criteria can judiciously select the optimal antenna set and allocate proper power and rate, and are very suitable for G-DWCS system
Personal, Indoor and Mobile Radio Communications, 2005. PIMRC 2005. IEEE 16th International Symposium on; 10/2005
[Show abstract][Hide abstract] ABSTRACT: The paper studies the downlink single user average capacity of a generalized distributed wireless communication system (G-DWCS). For equal transmission power, the upper bound and an approximate expression of the average capacity are derived. Transmit power can also be allocated in a water-filling like fashion which may further increase power utilization efficiency. In a random antenna layout, the capacity advantage of G-DWCS over standard cell multiple input multiple output (SC MIMO) systems is analysed. Also, sub-optimum antenna selection algorithms are proposed for maximization of the average capacity. Simulation results verify the capacity analysis and capacity improvement due to antenna selection algorithms.
[Show abstract][Hide abstract] ABSTRACT: In this paper, performance of smart antenna in multipath macrocell environment is studied. The system capacity and coverage of TD-SCDMA systems in the macrocell environment are studied and simulated without/with base station smart antenna which is used for dynamic channel allocation, beam forming and power control. System capacity and coverage of TD-SCDMA systems are found to be enlarged greatly by smart antenna. There exist many tradeoff issues that deserve careful planning between cell coverage, capacity, mobile user's maximum transmit power and number of smart antenna elements. For areas with different mobile user density, smart antennas with different elements are to be implemented to reduce costs.
Mobile Communications, 7th CDMA International Conference, CIC 2002, Seoul, Korea, October 29 - November 1, 2002, Revised Papers; 01/2002