This concerns the power allocation problem for the CogMFDR based on a OSTBC system.
K], selected from a signal constellation using the OSTBC matrix, [G.
R] encodes the source message using the same OSTBC and forwards the encoded signal matrix [G.
The OSTBC rate is assumed to be the greatest achievable value, see e.
Zhang, "Performance analysis of OSTBC transmission in amplify-and-forward cooperative relay networks," IEEE Transactions on Vehicular Technology, vol.
In , it has been shown that no rate 1 OSTBC exists for more than two antennas.
DOSTBC: it uses a rate 1/2 OSTBC matrix and 16QAM modulation.
Different from delay-free cases, it was found in  that the open-loop OSTBC may outperform the closed-loop spatial diversity techniques in terms of the system capacity when the feedback delay grows large.
In order to exploit both the spatial and multiuser diversities, we consider three joint diversity schemes, including multiuser TMRC (M-TMRC), multiuser TAS (M-TAS), and multiuser OSTBC (M-OSTBC).
The first two are closed-loop TMRC and TAS, and the last one is the open-loop OSTBC.
OSTBC is an attractive low complexity spatial diversity scheme with full diversity order , .