Cellular Multihop Communications: Infrastructure-Based Relay Network Architecture for 4G Wireless Systems

In cellular communications, the amount of total available resources (frequency-time plane) and the QoS requirements jointly determine the capacity per cell. And, the transmit power (especially in the reverse-link) and the propagation conditions determine the cell size. If the demand per cell happens to be (much) greater than the cell capacity, there exists a capacity shortage. Well-known solutions within the framework of the conventional cellular architecture can be used to increase the network capacity, such as cell splitting and microcell deployment. Solutions to the capacity shortage do not have to be very cost-effective as there exist customers to pay for the service in this scenario; in other words, capacity shortage does not constitute a real challenge. 2G cellular networks have been very successful because they have been mainly capacity limited. Similarly, if the demand in an area to be covered happens to be (much) less than the available capacity, then there is a coverage problem. Solving the coverage problem, on the other hand, constitutes a real challenge as the solution must be cost-effective (due to the saturated number of customers). One main challenge for 4G networks is the provision of high data rate coverage in a cost-effective manner.