摘要：This paper investigates joint design and optimization of both low density parity check （LDPC） codes and M-algorithm based detectors including iterative tree search （ITS） and soft-output M-algorithm （SOMA） in multiple-input multiple-output （MIMO） systems via the tool of extrinsic information transfer （EXIT） charts. First, we present EXIT analysis for ITS and SOMA. We indicate that the extrinsic information transfer curves of ITS obtained by Monte Carlo simulations based on output log-likelihood rations are not true EXIT curves, and the explanation for such a phenomenon is given, while for SOMA, the true EXIT curves can be computed, enabling the code design. Then, we propose a new design rule and method for LDPC code degree profile optimization in MIMO systems. The algorithm can make the EXIT curves of the inner decoder and outer decoder match each other properly, and can easily attain the desired code with the target rate. Also, it can transform the optimization problem into a linear one, which is computationally simple. The significance of the proposed optimization approach is validated by the simulation results that the optimized codes perform much better than standard non-optimized ones when used together with SOMA detector.

摘要：As one of the key characteristics in cognitive wireless networks(CWNs),network environment awareness techniques have received much attention *** of traditional spectrum sensing technology that suffers from problems of miss detection,false alarm,hidden node,and inefficiency,cognitive pilot channel(CPC) technology has been proposed as one of the candidate solutions for an efficient and accurate network information delivery scheme to user equipment(UE).The aim of the CPC technology is to provide the necessary information for the reconfiguration of the UE using the public signaling *** ensure the efficient information delivery,the whole geographical area covered by the CPC is divided into square meshes of the same ***,two typical network information transmission modes for CPC deployment are also proposed:broadcast CPC mode and on-demand CPC *** further improve the efficiency of network information delivery,an efficient dynamic mesh grouping scheme has been designed which is based on the fractal theory for the broadcast CPC mode,where adaptive rectangular sized meshes are used to approximately cover the whole *** to the traditional fixed size mesh division strategy,results show that the proposed dynamic mesh grouping scheme significantly reduces the number of meshes by grouping similar meshes together,and the average delay of receiving CPC information on the UE side is therefore reduced.

摘要：Cooperative communication networks have been studied and analyzed for many years for enhancing system performance,capacity,and reducing interference with the least focus on handover in cooperative communication *** paper focuses on trial field testing system for evaluating the proposed handover scheme called slide handover(HO).An automatic power allocation technique is coupled with slide HO scheme and its performance is also evaluated under cooperative *** proposed scheme has achieved 100%successful HO executions in our field trial *** error rate(BLER)and slide HO are tested and analyzed in this trial system,and it is shown that the capacity of cooperative networks in these trials implementation has improved and maintained the expected quality of *** below1%is noted at different testing locations which occasionally reached to 10%.Real-time video streaming performance is tested at different trial locations,and uniform streaming performance is noted at all different locations including during the HO *** implies the improved HO delay of the proposed slide HO as compared to traditional HO techniques.