Delay-Aware Admission Control and Beam Allocation for 5G Functional Split Enhanced Millimeter Wave Wireless Fronthaul Networks

Abstract

In this paper, we study a delay-aware admission control (AC) and beam allocation (BA) problem with the consideration of quality of experience (QoE) and dynamic variation of channel condition for centralized unit (CU) and distributed unit (DU) based functional split options (FSOs) in millimeter wave (mmWave) fronthaul downlink networks. The original optimization problem aims to maximize timeaverage QoE subject to delay and queue stability constraints. The intractability of the considered problem comes from the necessity to allocate resources across periods of time slots. After applying virtual queue transformation and Lyapunov optimization method, the targeting problem can be converted into two independent AC and BA sub-problems in each time slot. The converted problem involves actual and virtual queues, which causes conflicting tendency. With the design of a flexible Lyapunov function, the influences of actual and virtual queues are theoretically to be proved balanced. Moreover, the AC sub-problem can be solved by Karush-Kuhn-Tucker condition, whereas mmWave BA sub-problem is tackled by genetic algorithm and matching game for the CU-based and DU-based FSOs, respectively. Simulation results demonstrate the applicability of the proposed CU-/DU-based algorithms in terms of average data rate, admission control rate, queue length, and corresponding system delay under either uniform or dense deployment of DUs. Moreover, the proposed scheme achieves the lowest delay and highest QoE performances while sustaining the system stability compared with the state-of-theart mechanisms in open literatures.

QoE-Maximized Beam Assignment and Rate Control for Dynamic mm-Wave-Based Full-Duplex Small Cell Networks

“…The central scheduler is at the core unit and can access all the data processing. Note that the considered scenario is consistent with centralized architecture of functional split networks option, which is regarded as a feasible system in future networks [25]. The BA result of the considered network for each time slot determines the UEs' transmission rate at the physical layer; whereas the RC policy determines the served quality for a user by adjusting the amount of data entering into the queue backlogs at the application layer as indicated in [26].…”

“…Owing to the practical limitations in the SWB system expressed in (24) to (25), spatial multiplexing cannot be utilized in the considered network. The SWB system is adopted in this study because it is one of the mainstream techniques for multi-user systems in mm-wave bands.…”

“…As dynamic variation of channel condition over time slots is considered in this paper, channel condition fluctuates between relatively poor and good quality (which is reflected by different queue lengths over time slots), there exists certain time slots that have worse channel conditions than the others. Figure 4 depicts the QoE performance of the proposed DBR algorithm by studying s D k and s U m versus V when the UEs' QoE requirements (U max D k , U max U m ) are chosen as (16,12), (20,16) and (25,20). It can be observed that the QoE is improved as V increased.…”