Designing wireless radio access networks for third generation cellular networks

In third generation (3G) cellular networks, base stations are connected to base station controllers by point-to-point (usually T1/E1) links. However, today's T1/E1 based buck haul network is not a good match for next generation wireless networks because symmetric T1s is not an efficient way to carry bursty and asymmetric data traffic. In this paper, we propose designing an IEEE 802.16-based wireless radio access network to carry the traffic from the base station to the radio network controller. 802.16 has several characteristics that make it a better match for 3G radio access networks including its support for time division duplex mode that supports asymmetry efficiently. In this paper, we tackle the following question; given a layout of base stations and base station controllers, how do we design the topology of the 802.16 radio access network connecting the base stations to the base station controller that minimizes the number of 802.16 links used while meeting the expected demands of traffic from/to the base stations? We make three contributions: we first show that finding the optimal solution to the problem is NP-hard. We then provide heuristics that perform close to the optimal solution. Finally, we address the reliability issue of failure of 802.16 links or nodes by designing algorithms to create topologies that can handle single failures effectively.