Wireless Communications
Elements of Information Theory (Wiley Series in Telecommunications and Signal Processing)
Elements of Information Theory (Wiley Series in Telecommunications and Signal Processing)
Keyholes, correlations, and capacities of multielement transmit and receive antennas
IEEE Transactions on Wireless Communications
Keyhole Effect in MIMO Wireless Channels: Measurements and Theory
IEEE Transactions on Wireless Communications
On the Error Probability of Orthogonal Space-Time Block Codes Over Keyhole MIMO Channels
IEEE Transactions on Wireless Communications
IEEE Transactions on Wireless Communications
IEEE Transactions on Information Theory
On the capacity of MIMO relay channels
IEEE Transactions on Information Theory
On the Outage Capacity Distribution of Correlated Keyhole MIMO Channels
IEEE Transactions on Information Theory
IEEE Communications Magazine
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A MIMO keyhole is a propagation environment such that the channel gain matrix has unit rank (single degree of freedom), irrespective of the number of deployed antennas or their correlations (spacing), thereby reducing the MIMO channel capacity to that of a SISO channel. Related literature seems to consider such degeneration hopeless. Contrary to this general belief, this paper demonstrates that cooperative diversity can mitigate keyhole effects. Precisely, provided that the source-relay channel is keyhole-free, we show that there exists a "cutoff" relay transmit power above which keyhole effects can be mitigated even when both the source-destination and the relay-destination channels incur keyhole effect. We explicit the closed form of this power threshold as function of the source transmit power and the channel matrices brought into play in the relay channel. Numerical examples confirm the relevance of our claim.