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—The problem of efficient communication over a scalar quasi-static fading channel is considered. The single-layer transmission (SLT) and multi-layer transmission (MLT) schemes do not require any knowledge of the channel state information (CSI) at the transmitter, but their performance is also limited. It is shown that using Hybrid-ARQ (HARQ) can(More)
Opportunistic Spatial Orthogonalization (OSO) is a cognitive radio scheme that allows the existence of secondary users and hence increases the sum throughput, even if the primary user occupies all the frequency bands all the time. The key idea is to exploit the spatial dimensions to orthogonalize users and hence minimize interference. However, unlike the(More)
This paper focuses on studying the fundamental performance limits and linear dispersion code design for the MIMO-ARQ slow fading channel. The optimal average rate of well-known HARQ protocols is analyzed. The optimal design of space-time coding for the MIMO-ARQ channel is discussed. Information-theoretic measures are used to optimize the rate assignment and(More)
We investigate the effectiveness of cooperative diversity in interference limited ad hoc networks. The underlying cooperative techniques exploit space diversity through cooperative terminals' relaying signals for one another. We develop relay selection policy and channel allocation scheme to provide contention-free transmissions while acquiring capacity(More)
The performance analysis of the Zero-Forcing Successive Interference Cancellation (ZF-SIC) detector in Vertical Bell Labs Layered Space-Time (V-BLAST) is generally considered difficult mainly because of the nonlinear error propagation effect. In this paper we first present the nearly exact bit error rate (BER) analysis of ZF-SIC V-BLAST with Binary(More)
The paper provides an overview of a real-time spectrum sensing prototype operating in the TV white space. There has been considerable research on the feasibility of spectrum sensing in the TV white space. This is a challenge due to the very weak signal power levels specified by the FCC. In the TV white space there are a number of incumbent systems that must(More)
—We study the problem of optimal resource allocation for multiuser multiaccess wireless video communication from an information-theoretic point of view. We derive the optimal resource allocation policies by directly maximizing at the application layer the weighted sum of video qualities of all users, subject to information-theoretic multiaccess capacity(More)
This paper considers an uplink cellular system, in which each base station (BS) is equipped with a large number of antennas to serve multiple single-antenna user equipments (UEs) simultaneously. Uplink training with pilot reusing is adopted to acquire the channel state information (CSI) and maximum ratio combining (MRC) or zero forcing (ZF) reception is(More)