Abstract: The variation of the distances between the base station and the border areas of hexagon shape of the mobile leads to the existence of certain dead zones (gaps) in the coverage at the border of the cell. Relay station is a promising solution to enhance coverage in these gaps. Furthermore, these relay stations can also be used to enhance the capacity of network by using Load Balance Technique. This study discusses the effect of adding three relay stations to the network. Results show that with proper frequency plan for assign channels to relays, relaying can have a significant effect on the coverage, the outage probability, average spectral efficiency and call blocking probability.