Journal ArticleDOI
Multiple-antenna channel hardening and its implications for rate feedback and scheduling
TLDR
A central limit theorem is proved for MIMO channels with a large number of antennas, which is described as a "channel-hardening" result for data and voice services, scheduling, and rate feedback.Abstract:
Wireless data traffic is expected to grow over the next few years and the technologies that will provide data services are still being debated. One possibility is to use multiple antennas at base stations and terminals to get very high spectral efficiencies in rich scattering environments. Such multiple-input/multiple-output (MIMO) channels can then be used in conjunction with scheduling and rate-feedback algorithms to further increase channel throughput. This paper provides an analysis of the expected gains due to scheduling and bits needed for rate feedback. Our analysis requires an accurate approximation of the distribution of the MIMO channel mutual information. Because the exact distribution of the mutual information in a Rayleigh-fading environment is difficult to analyze, we prove a central limit theorem for MIMO channels with a large number of antennas. While the growth in average mutual information (capacity) of a MIMO channel with the number of antennas is well understood, it turns out that the variance of the mutual information can grow very slowly or even shrink as the number of antennas grows. We discuss implications of this "channel-hardening" result for data and voice services, scheduling, and rate feedback. We also briefly discuss the implications when shadow fading effects are included.read more
Citations
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Journal ArticleDOI
Cognitive radio: brain-empowered wireless communications
TL;DR: Following the discussion of interference temperature as a new metric for the quantification and management of interference, the paper addresses three fundamental cognitive tasks: radio-scene analysis, channel-state estimation and predictive modeling, and the emergent behavior of cognitive radio.
Journal ArticleDOI
Capacity limits of MIMO channels
TL;DR: An overview of the extensive results on the Shannon capacity of single-user and multiuser multiple-input multiple-output (MIMO) channels is provided and it is shown that the capacity region of the MIMO multiple access and the largest known achievable rate region (called the dirty-paper region) for the M IMO broadcast channel are intimately related via a duality transformation.
Book
Random Matrix Theory and Wireless Communications
Antonio M. Tulino,Sergio Verdu +1 more
TL;DR: A tutorial on random matrices is provided which provides an overview of the theory and brings together in one source the most significant results recently obtained.
Journal ArticleDOI
Guaranteeing Secrecy using Artificial Noise
Satashu Goel,Rohit Negi +1 more
TL;DR: This paper considers the problem of secret communication between two nodes, over a fading wireless medium, in the presence of a passive eavesdropper, and assumes that the transmitter and its helpers (amplifying relays) have more antennas than the eavesdroppers.
References
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Layered space-time architecture for wireless communication in a fading environment when using multi-element antennas
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