Load Balancing Relay for Two-Tier MTC Uplink

A Load Balancing Relay Algorithm (LBRA) is proposed in this letter to solve the unfair spectrum resource allocation problem in two-tier machine-type communications (MTC) uplink transmission. By adopting MTC devices (MTCDs)'s distribution, spectrum resources are dynamically allocated and reclustered for the link between MTCDs to cluster-head. Moreover, the system outage probability and transmission capacity are derived for the LBRA in this letter. The numerical results provide some insights on potential use of the LBRA for the scenario with high MTCD density.