How do you deal with heterogeneous traffic and user mobility in radio admission control in 3G networks?

1 RAC principles and objectives

RAC is responsible for allocating radio resources to the active users and managing the admission of new users in a 3G network. RAC has two main objectives: to maximize the network utilization and to ensure the QoS of the accepted users. To achieve these objectives, RAC has to balance the trade-off between accepting more users and maintaining the radio quality. RAC also has to consider the fairness among different traffic types and users, as well as the network policies and priorities.

2 RAC methods and criteria

RAC can be implemented with various methods and criteria, depending on the network architecture and the traffic characteristics. For example, the fixed capacity method assigns a fixed amount of radio resources to each traffic type and admits new users until the resources are exhausted. The fractional load method admits new users based on the fraction of total load that each traffic type can generate, taking into account QoS parameters and channel conditions. Additionally, the effective bandwidth method estimates the effective bandwidth of each traffic type and admits new users based on available bandwidth and QoS constraints. Finally, the utility-based method evaluates the utility of each traffic type and admits new users based on utility maximization and QoS satisfaction.

3 RAC challenges and solutions

RAC faces several challenges in 3G networks, such as heterogeneous traffic, user mobility, and interference. To address these challenges, RAC can implement traffic classification and differentiation, use adaptive and predictive techniques, and manage interference and power control. Traffic classification involves assigning different priorities and weights to different QoS requirements. Adaptive RAC involves dynamically adjusting the admission criteria and resource allocation. Predictive RAC involves predicting future traffic demand and channel quality based on historical data and mobility patterns. Interference management entails controlling the number of users and code allocation in each cell. Power control adjusts the transmit power of each user based on their channel conditions and QoS requirements.