Deployment of multi-layer TDMA cellular network with distributed coverage for traffic capacity enhancement

In second generation TDMA cellular systems, traffic increase is achieved via cell size reduction. But, to handle moving mobile stations (MS) and ensure coverage on the whole served area, a 2-layer network has to be deployed and radio resource management techniques such as directed retry (DR) are implemented for spectrum efficiency. Optimally, fast (respectively, slow) moving MS should be served by the macrocell (respectively microcell) layer. So, in such network organization, traffic performance is sensitive to both coverage quality and accuracy of estimation of MS speed. Conventional microcell layer deployment suffers from coverage holes and uncertainty of speed estimate (making it impossible to exploit the full capacity of such networks). This paper proposes to replace the usual layer of microcells by a distributed coverage. Strategies for serving base transceiver station (BTS) selection and channel allocation dependent on MS position over the service area, are implemented. Both the communication quality and the accuracy of estimation of MS speed are improved. This makes DR more efficient and enhances the overall traffic performance.