C-RAN回傳網絡中下行資源調度策略
A downlink resource scheduling strategy for C-RAN backhaul network
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摘要: 隨著移動互聯網技術的快速發展、無線終端設備與移動應用流量需求與日俱增,移動用戶對無線通信網絡的服務質量(quality of service, QoS)要求越來越高、回傳網絡的壓力也越來越大. 新出現的云無線接入網(cloud radio access network, C-RAN)能夠有效提升網絡容量、提高用戶服務質量,同時采用無源光網絡(passive optical network, PON)作為其回傳網絡(backhaul),能夠為其提供大帶寬、高可靠、低時延的回傳支撐. 在移動應用需求不斷變化和回傳網絡資源有限的條件下,高效的資源調度策略至關重要,其能夠有效的提升回傳網絡資源利用率、降低傳輸等待時延. 為節約回傳網絡波長資源、提高波長負載均衡性和資源利用率,提出一種下行資源調度策略. 根據高熱點區域無線用戶實時網絡需求,綜合考慮回傳網絡波長使用數量、負載均衡性和實時業務分配均勻度等優化目標,采用自適應權重并行遺傳算法完成其優化過程,從而實現波長資源動態分配,提升網絡資源利用率. 仿真結果表明,提出的下行資源調度策略能有效提高網絡負載均衡性和網絡資源利用率,并降低實時業務等待傳輸時間.Abstract: With the rapid development of mobile internet technology and daily increase in wireless user equipment as well as demand of mobile applications, the required quality of service (QoS) by mobile users for wireless communication networks is increasing, and the pressure of backhaul network is also increasing. The emerging cloud radio access network (C-RAN) can effectively improve the network capacity and user service quality. Meanwhile, Passive Optical Network (PON) was used for backhaul network that offers a large bandwidth, high reliability, and low latency backhaul. When the demand of mobile applications is ever-changing and backhaul network resource is limited, an efficient backhaul network resource scheduling strategy is of great importance. This can improve the backhaul network resource utilization and waiting-transmitting delay in C-RAN. To save backhaul network resource, improve the load balance of wavelengths and the utilization of network resource, a downlink resource scheduling strategy was proposed. According to the network demand of wireless users in hot spots, three optimization objectives including the number of used wavelengths, load balance, and well-distribution of real-time traffic were considered in the optimization of adaptive-weighted parallel genetic algorithm. Thus, the wavelength resources were dynamically allocated and resource utilization was improved. The results demonstrate that the proposed downlink resource scheduling strategy can effectively improve the load balance and resource utilization and reduce the waiting-transmitting delay of real-time traffic.