In this letter, we derive a lower bound on the diversity multiplexing tradeoff (DMT) in multiple-input multiple-output (MIMO) nonorthogonal amplify-and-forward (NAF) cooperative channels with resolution-constrained channel state feedback. It is shown that power control based on the feedback improves the DMT performance significantly in contrast to the no-feedback case. For instance, the maximum diversity increase is exponential in K with K-level feedback.

Cooperative relay selection, in which one of multiple relays is selected to retransmit the source signal to the destination, has received considerable attention in recent years, because it is a simple way to obtain cooperative diversity in wireless networks. The exact expression of outage probability for a decode-and-forward cooperative relay selection with multiple source and destination antennas over Rayleigh fading channels was recently derived in [9]. In this letter, we derive the exact expressions of outage probability and diversity-multiplexing tradeoff over independent and non-identically distributed Nakagami-m fading channels as an extension of [9]. We then analyze the effects of various parameters such as fading conditions, number of relays, and number of source and destination antennas on the outage probability.

In this letter, the diversity-multiplexing tradeoff (DMT) function for a special half-duplex dynamic decode and forward (DDF) relay protocol using two source-antennas, two destination-antennas, and more than two relay-antennas is derived. It is shown that the performance of the DDF relay protocol can be substantially improved by increasing the relay-antenna number, but only for low multiplexing gains.

In this paper, we consider multiple source and destination antennas based on relay selection scheme to improve the end-to-end outage performance for decode-and-forward cooperative networks. We derive an exact closed-form expression of the outage probability for the proposed system over a Rayleigh fading channel and describe the diversity-multiplexing tradeoff of the system. We then analyze the effects of the number of source and destination antennas on the outage probabilities and diversity-multiplexing tradeoffs.

The concept of regional diversity-multiplexing tradeoff (DMT) is introduced by extending the asymptotic outage probability expression for multiple-input multiple-output (MIMO) channels. It is shown that for both Rayleigh and Rician MIMO channels, the regional diversity gain is a linear function of the regional multiplexing gain and that the original DMT curve can be obtained from the set of regional DMT lines. As a result, vital information for capturing both finite and infinite signal-to-noise ratio characteristics in terms of DMT is provided.

In this paper, a new framework to characterize the tradeoff between diversity and multiplexing gains of Multi Input Multi Output (MIMO) wireless systems at finite Signal to Noise Ratios (SNRs) is presented. By suitable definitions of non-asymptotic diversity and multiplexing gains, we extract a useful tool to investigate the performance of space-time schemes at finite SNRs. Exact results on the diversity-multiplexing tradeoff (DMT) are derived for Multi Input Single Output (MISO), Single Input Multi Output (SIMO), and 22 MIMO channels. We show that our outcomes coincide with the Zheng and Tse's results at high SNRs. When the new definitions of non-asymptotic diversity and multiplexing gains are used, the resulted DMT converges to its asymptotic value at realistic SNRs. Furthermore, using these definitions enables the diversity gain to represent the outage probability with reasonable accuracy.