Blockage-Aware Power Allocation and Relay Selection in Millimeter-Wave Small Cell Network

Millimeter wave (mm-wave) communication technology promises to provide higher data rates as the spectrum is highly under-utilized and more amount of spectrum can be allocated. However, mm-wave cannot travel longer distances and it is sensitive to blockages. The former issue can be dealt with via the small cell technology. Small cell technology can increase the spectral efficiency of the system if the resources are efficiently utilized. The transmission distance between the mobile user and the small cell access point is reduced and it makes an ideal candidate for the use of mm-wave. However, the latter issue of blockages still needs to be handled in order to exploit the full benefits of mm-wave in small cell network. In this paper, a blockage-aware allocation of resources for a mm-wave small cell network is investigated. Our objective is to maximize the downlink sum-rate of all users such that the quality of service (QoS) and power constraints are satisfied. The formulated problem takes into consideration the presence of blockages and the best link (both LOS and relay, only LOS, only relay) possible. We propose a blockage-aware relay selection and power allocation algorithm (BARSPAA) for mm-wave in small cells. The BARSPAA algorithm is compared with exhaustive and bounded exhaustive search algorithms. Numerical results show that the proposed BARSPAA achieves a significantly close performance while the algorithm complexity is much reduced.