Effect of Bandwidth and Spreading Codes on Spectrum Utilization of Spectrally Overlaid CDMA Systems
نویسندگان
چکیده
In this paper, we analyze capacity and spectrum utilization of spectrally overlaid systems using single-code CDMA (SC-CDMA) and multi-code CDMA (MC-CDMA) techniques according to varying system parameters. The spectrum utilization defined as maximally achievable total throughput in the overlaid systems is compared with that of the un-overlaid systems. Analytical results show that the dominant parameter affecting the performance of the overlaid systems is the spectrum overlay ratio. Namely, multiuser interference is a dominant factor to affect the system performance comparing with mutual interference among multiple spreading codes assigned to users. Hence the use of SCCDMA technique is more desirable than MC-CDMA scheme for a higher capacity and spectrum utilization in spectrally overlaid CDMA systems.
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