We consider the analysis of in nite half-duplex systems which consists of nite state machines that communicate over unbounded channels. The property half-duplex for two machines and two channels (one in each direction) says that each reachable state has at least one channel empty. The contributions of this paper are (a) to give a nite description of the reachability set of such systems, which h...

In this paper, we present preliminary results on achievables rates in half-duplex cooperative multiple access channels (CMAC). We show that the upper bound on the capacity of the half-duplex CMAC can be solved using convex optimization techniques. Under a Gaussian model, we study the maximal achievable rate by every node in the network. We propose a number of scenarios, encompassing existing an...

New families of computation-efficient parallel prefix algorithms for message-passing multicomputers are presented. The first family improves the communication time of a previous family of parallel prefix algorithms; both use only half-duplex communications. Two other families adopt collective communication operations to reduce the communication times of the former two, respectively. The precond...

In this paper, we propose a novel reception/transmission scheme for half-duplex base stations (BSs). In particular, we propose a half-duplex BS that employes in-band uplink-receptions from user 1 and downlink-transmissions to user 2, which occur in different time slots. Furthermore, we propose optimal adaptive scheduling of the in-band uplink-receptions and downlink-transmissions of the BS such...

As a key in cognitive radio networks (CRNs), dynamic spectrum access needs to be carefully designed to minimize the interference and delay to the primary (licensed) users. One of the main challenges in dynamic spectrum access is to determine when the secondary (unlicensed) users can use the spectrum. In particular, when the secondary user is using the spectrum, if the primary user becomes activ...