Muhammad Nazmul Islam

Integrated Access Backhaul in Millimeter Wave Networks

High spatial reuse through densification of wireless networks and higher amount of bandwidth are necessary to meet the increase of wireless demand in the next decade. Small cells that operate at millimeter wave (MMW) band can fulfill these two criteria. Deploying fiber to many small cell MMW base stations can be expensive and wireless backhaul can reduce this cost. A fixed access backhaul network - where the available resource is fixed separately for access and backhaul links - cannot meet the dynamic traffic demand of the network. An integrated access backaul (IAB) network - where the summation of available resource is fixed for access and backhaul links - can dynamically change the partition between access and backhaul links and meet instantaneous demand of UEs acrosss the network. This work focuses on joint cost optimal fiber drop deployment, resource allocation and routing in an IAB network. Simulation results show that IAB can significantly reduce the fiber drop deployment cost of the network compared to fixed access backhaul network.

Coverage and capacity of 28 GHz band in indoor stadiums

High user density in stadiums and auditoriums is a challenging scenario for deploying future generation wireless networks. Due to the almost line-of-sight propagation model, the LTE base stations and WiFi access points would interfere with each other and result in reduced throughput in this scenario. Millimeter and microwave bands can play an important role in this regard due to their spatial reuse capability. This paper focuses on the coverage and capacity of the 28 GHz band in indoor stadiums and auditoriums. We model an indoor basketball stadium and human blockage loss. We consider two different types of human blockage models: (i) knife edge diffraction model and (ii) experimental blockage model. We develop the experimental blockage model while making measurements in a small-scale stadium-like seating area. Our experiments suggest that the boresight direction is irrelevant in the presence of multiple surrounding scattering objects. Scattering and reflections of signals from neighboring human bodies can provide strong signal paths at the millimeter wave band in indoor stadiums. Based on this model, we simulate the connectivity of the 28 GHz band with different sitting and standing patterns among audience. Simulation results suggest that ten base stations can sustain a sum rate of 76 Gbps and 227 Gbps with one and four RF chains respectively in 50 percentile case. We also show that the 28 GHzs sustainable data rate can be 11 and 33 times higher than the 5 GHzs sustainable data rate with one and four RF chains respectively.