Adaptive traffic-load shedding and its capacity gain in CDMA cellular systems

Abstract

In a situation such as a traffic accident on a highway, the active mobiles in an affected cell may easily outnumber the capacity, and an excessive increase in CDMA noise may, in the worst case, block all calls in the cell if the users insist on calling through the same cell site. A scheme to alleviate such congestion in CDMA cellular systems is proposed, so that traffic load is adaptively shed from affected cells by forced hand-offs of the mobiles farthest away from current cell site. The capacity with adaptive load shedding is studied by computer simulations considering two scenarios: a single congested cell with six neighbouring cells partially loaded, and three consecutive congested cells with four neighbouring cells partially loaded. The results show that the scheme offers higher CDMA cellular capacity gain than the normal power-up control adopted by the current CDMA cellular standard.