The corDECT wireless local loop: Capacity predictions

The traditional wired local loop used to connect each telephone subscriber to the nearest exchange is expensive and unreliable. Wireless Local Loop (WLL) systems largely eliminate these copper wires using wireless technologies and could provide a cost effective solution. corDECT is one such WLL system, based on the DECT (Digital Enhanced Cordless Telecommunications) standard, that provides toll-quality voice and data capability at a cost below that of a wired local loop. Using micro-cells and Dynamic Channel Selection (DCS), it can handle high subscriber densities without frequency planning. corDECT is gaining commercial acceptance in India and a number of other countries. Using a simple Queueing Network Model (QNM), we find that the 1,000-line corDECT system could achieve a Busy Hour Call Attempt (BHCA) of 36,000 calls/hour, which is far greater than its requirement of 20,000 calls/hour. We show how the system could be expanded to a 10,000-line exchange with a BHCA of over 2,10,000 calls/hour. We also investigate the feasibility of implementing 64 kbps data service along with voice. It is shown that this requires modest hardware improvements.