Latency Reduction for Mobile Backhaul by Pipelining LTE and DOCSIS

Abstract: The small cell market has been growing. To backhaul wireless traffic from small cells, the mobile network operators (MNOs) are looking into economically viable solutions, specifically the hybrid fiber coaxial networks (HFC), in addition to the traditional choice of fiber. When the latencies from both the wireless and the HFC networks are added together, it can result in noticeable end-to-end system latency, particularly under network congestion. If the two networks could somehow coordinate with each other, it would be possible to decrease the total system latency and increase system performance. In this paper, we propose a method to improve upstream user-to-mobile core latency by coordinating the LTE and HFC scheduling. The method reduces the impact on system latency from the HFC network's request-grant-data loop, which is the main contributor of backhaul upstream latency. Through simulation, we show that coordinated scheduling improves overall system latency.