Short message service and paging cluster size impact on the DCCH capacity (TIA/EIA/IS-136)

This paper evaluates the signaling capacity of the digital control channel (DCCH) on both downlink and up-link on the basis of the short message service (SMS), the number of mobile stations (MS) in a paging cluster and the SMS transaction rate per MS. Performance figures such as voice call setup message failure rate, SMS failure rate, and MS registration failure rate are assessed as a function of different loading factors. Simulations show that the down-link SMS traffic has no impact on voice call setup procedures if a higher priority is assigned to voice call setup messages. However, the up-link SMS traffic can impact voice call set up capability if the up-link SMS transaction rate is high. Simulations show that for the same SMS failure rate, the up-link DCCH can handle more SMS transactions per MS than the down-link DCCH. The impact of the number of MSs within a paging cluster on the SMS failure rate can also be significant. This paper investigates the relationship between the number of MSs in the paging cluster, the SMS transaction rate per MS, and the down-link SMS blocking rate.