Backhaul Resource Allocation for Existing and Newly Arrived Moving Small Cells

Cellular users in moving vehicles such as buses and trains have been suffering from quality-of-service (QoS) issues. Small-cell access points (SAPs) can be deployed in the vehicles to combat this problem. We call the SAPs deployed in vehicles moving SAPs (M-SAPs). With a small cell, two links are created in the macrocell, namely, the access link and the backhaul link. The macrocell may work as the backhaul for an M-SAP. Due to the mobility of the vehicle, an M-SAP will be entering and leaving the macrocell, and the backhaul connection will be changing. As the backhaul is wireless, resources will be required for data transmission from the macrocell to M-SAP, in addition to resources required for transmission from M-SAP to the user. In the existing research, backhaul resources are reserved for the newly arrived M-SAPs and not optimally utilized. In this paper, we study the allocation of orthogonal frequency-division multiple-access (OFDMA) resources (resource blocks and transmission power) to macrocell users and the backhaul of M-SAPs in the downlink of the network. Both the existing and newly arrived M-SAPs are considered in the macrocell. The objective is to maximize the achievable data rate of the newly arrived M-SAPs in the macrocell under the constraint that the minimum required achievable data rates of the existing macrocell users and the M-SAPs are satisfied.