Ad Hoc Networks Oriented Distibuted Space-Time Coding Techniques

In cooperative communication, DSTC (Distributed Space-Time Coding)technology, which is the application of STC (Space-Time Coding) in “Virtual MIMO”,can improve the system performance by cooperation among single antenna mobilestations (nodes). DSTC can be used in some networks which has limited power, size andcost. Researches on DSTC mostly relate to relay selection and power allocation, buthardly from the point of view of transmission distance. The potential of distributedAlamouti coding in extending transmission distance will be researched in this thesis.This thesis researches two cooperative models in Ad hoc network: three nodes (oneAF relay) model and four nodes (two AF relays) model. With the analysis of codingmethod for the problem of ISI (Inter Symbol Inteference) in distributed Alamouticoding, theoretical analysis and simulations of the performance of distributed Alamouticoding are carried out from the point of view of transmission distance. Results indicatethat different conditions, i.e. models, path loss factors and BER, can cause differenttransmission performance. Compared with one transmission of SISO, one transmissionof distributed Alamouti coding has a maximum extension of6.6in both two models, theextension in four nodes model is bigger than1, but the extension in three nodes modelmaybe less than1with a small probability. All in all, the application of distributedAlamouti coding in Ad hoc network can obtain a huge distance extension, in otherwords, it can save energy and improve the lifetime of the whole Ad hoc network greatlyif the transmission distance is the same as SISO.