Mc-ss System, The H-arq

The evolution of digital communication has increased the demands for reliable data communication. But multi paths and Doppler shift will severely degrade the system performance Under poor channel conditions, specially in high data rate and high speed environment. Thus efficient error control technique becomes a major concern of current wireless communication. So far there are two kinds of technique used for error control: FEC (Forward Error Correction) and ARQ (Automatic Repeat Request). Hybrid ARQ(Hybrid Automatic Repeat Request), which combines the high efficiency of FEC and reliability of ARQ, is used in 3G/B3G or future wireless mobile communication system broadly to match the various requirements of Qos (Quality of service) for data service.In MAGNET(My Personal Adaptive Global Net) air interfaces for PANs(Personal Area Networks) are investigated. SISO-MC-SS(single input single output Multi-Carrier Spread Spectrum) System is one of Candidate air interfaces for the high data rate (HDR).SISO-MC-SS is an OFDM based air interface with spreading in frequency domain. In this Paper,three kind of H-ARQ schemes combined with SISO-MC-SS system are proposed to improve the performance of SISO-MC-SS system.Then simulation paramters are setup and simulation results are compared between various schemes.Antenna array at both the transmitter and receiver to transmit multiple data streams,termed the MIMO technology, can be used to increase spectral efficiency. V-BLAST (Vertical Bell Laboratories Layerd Space-Time) can be combined with OFDM to achieve high data rate transmission in frequency selective fading channels .As OFDM effectively divides the frequency selective channel into a number of flat fading subchannels..Combined with HARQ and OFDM, MIMO can potentially provide higher throughput packet data services with higher reliability...