Generalized spatial modulation (GSM) uses N antenna elements but fewer
radio frequency (RF) chains (R) at the transmitter. Spatial modulation and
spatial multiplexing are special cases of GSM with R=1 and R=N,
respectively. In GSM, apart from conveying information bits through R
modulation symbols, information bits are also conveyed through the indices of
the R active transmit antennas. In this paper, we derive lower and upper
bounds on the the capacity of a (N,M,R)-GSM MIMO system, where M is the
number of receive antennas. Further, we propose a computationally efficient GSM
encoding (i.e., bits-to-signal mapping) method and a message passing based
low-complexity detection algorithm suited for large-scale GSM-MIMO systems.Comment: Expanded version of the IEEE Communications Letters pape