Multiuser decision-feedback detectors (DFDs) for direct-sequence code-division multiple access, based on the minimum mean-squared error (MMSE) performance criterion, are described. Both successive and parallel feedback (interference cancellation) with hard decisions are considered. An iterative DFD is presented, which consists of cascaded DFDs, each performing successive cancellation. The two-s...

We consider a MIMO fading broadcast channel and compute achievable ergodic rates when channel state information is acquired at the receivers via downlink training and explicit channel feedback is performed to provide transmitter channel state information (CSIT). Both “analog” and quantized (digital) channel feedback are analyzed, and digital feedback is shown to be potentially superior when the...

Random linear network coding (RLNC) is asymptotically throughput optimal in the wireless broadcast of a block of packets from a sender to a set of receivers, but suffers from heavy computational load and packet decoding delay. To mitigate this problem while maintaining good throughput, we partition the packet block into disjoint generations after broadcasting the packets uncoded once and collec...

To combat the detrimental effects of the variability in wireless channels, we consider cross-layer rate adaptation. We study communication systems that utilize the limited feedback in the form of linklayer Automatic Repeat-reQuest (ARQ) to maximize the physical-layer transmission rate, subject to a certain upper bound on the expected packet error rate. We assume that there is no knowledge of th...

The closed-loop transmit diversity technique is used to increase the capacity of the downlink channel in multiple-input-multiple-output (MIMO) communication systems. The WCDMA standard [1] endorsed by 3GPP [2] adopts two modes of downlink closedloop schemes based on partial channel information that is fed back from the mobile unit to the base station through a low-rate uncoded feedback bit stre...