Resource Allocation Strategies for Linear Symmetric Wireless Networks with Relays

Fourth Generation wireless networks could potentially incorporate novel wireless network architectures such as hierarchical, ad-hoc, pico-cell, etc. We consider a cellular architecture with relays that can store and forward information from the base station to the terminals on the downlink and from the terminals to the base station on the uplink. We study optimal time-allocation strategies for a network with relays and determine the consequent capacity gains. We focus on the case when the cellular structure is one-dimensional and evaluate the sensitivity of the capacity gains to key system parameters such as relay power, self-noise, relay location and terminal locations. We show that the optimal time allocation problem on both uplink and downlink, with the objective of maximizing the manimum common throughout of all the users in the cell, can be formulated as a linear program. We derive several analytical conditions that any optimal allocation much satisfy yielding simpler linear programs. We also present a sub-optical allocation algorithm that does not require the solution of a linear program. Resource allocation with inter-cell coordination across multiple cells is another feature that is expected to play a significant role in next generation wireless networks. We extend a previous work on inter-cell coordination to include soft handoff and exhibit that soft handoff gains over inter-cell coordination are not significant in our setting without fading. We compare the performance of the relay allocation schemes against that of inter-cell coordination schemes with and withour soft handoff, and also against the baseline scheme, which has intra-cell coordination only. We conclide that for the particular scenario considered here, relays provide an excellent means of enhancing maximum common throughout without the requirements of inter- cell allocation or soft handoff, while providing a performance that is comparable, or even superior to, both such schemes.