Incremental Deployment with Self-Backhauling Base Stations in Urban Environment

High capacity mobile broadband access requires a dense infrastructure of base stations. The costs associated with the backhaul transmission for these base stations is often a significant part of the total cost of the access network. It has been proposed to use part of the available spectrum to route data between base stations, so-called in-band relaying or self-backhauling. Although self-backhauling may result in a lower total system capacity, we will in this paper show examples where temporary use of in-band relaying postpones investments in fixed backhaul connections. This reduces the total (life-time) cost of the access network. In our incremental strategy example the total cost savings are in the order of 5 to 10%, depending on the relation between the additional equipment cost and the cost of leasing the fixed backhaul. Self-backhauling is not worth implementing when the entire network capacity needs to be achieved up-front, but the savings are significant when service uptake is slow or difficult to predict. The discount rate used in the investment analysis has only a minor impact on the results.