Abstract
Mobile communication systems have evolved considerably in recent years encouraging the deployment of multiple systems or multi-cellular technology. Quality of service (QoS) offered to mobile users improves from one system to another for example 4G systems, offer better QoS than that offered by 3G and 3.5G systems. In addition, 4G systems such as LTE (Long Term Evolution) can expand cellular coverage and provide higher throughput. New technologies enhance accessibility to the Internet. Migration services from Internet to mobile networks become an important research topic for telecommunications sector. This paper calculates and evaluates system performance by developing a new LTE mechanism for allocating resources in the downlink based on call admission control (CAC) taking into account mobility within and between cellular users. This mechanism uses adaptive modulation and coding (AMC) that divided the geographical area into several concentric regions. With this mechanism each call accepted by the system maintains its initial throughput regardless of the position of the user in the cell.