Chain-based multi-hop wireless backhaul networks (WBN) have attracted considerable attention in next-generation networks since they can cost-effectively extend the service coverage area. The major challenge pertaining to such networks is the designing of a high-performance medium access control (MAC) scheme to raise the end-to-end throughput and ensure fairness. In this paper, we propose a novel MAC protocol that is aimed at resolving the well-known location-dependent unfairness problem of chain-based networks, maximizing spatial reuse, and most importantly, achieving exceptional end-to-end throughput. Our scheme provides an elaborate control mini-slots design that resolves the different-relay-traffic-load problem of nodes at various positions near or far from the gateway and further provides local-traffic fairness among all nodes. Moreover, based on the traffic analysis, we provide a four-node group-transmission methodology. By using the neighbor-nodes echoes (broadcasts) the reservation-signals design, the chain-based WBN is allowed to extend to numerous nodes for concurrent and collision-free data transmission through distributed scheduling. Extensive simulation and analytic results also demonstrate that our proposed MAC scheme achieves exceptional system throughput which is approximately 1.6 times better than previous works for a four-node-chain network and also attains high system performance under a wide range of traffic loads and various system parameters.