本文選題：無線資源管理 + 正交頻分復用��； 參考：《西南交通大學》2014年博士論文

【摘要】：正交頻分復用(OFDM)/正交頻分復用多址(OFDMA)和中繼(Relay)技術相結合的多跳中繼網(wǎng)絡由于具有高頻譜效率、增強覆蓋、組網(wǎng)靈活,布網(wǎng)成本低等眾多優(yōu)點,已成為業(yè)界公認的下一代無線網(wǎng)絡的主流架構。與傳統(tǒng)蜂窩網(wǎng)絡相比,基于OFDM/OFDMA技術的中繼網(wǎng)絡面對的環(huán)境更加復雜,使得無線資源管理問題變得更具挑戰(zhàn)性：一方面,資源分配的維度由傳統(tǒng)的時域、頻域或空域向多維空間聯(lián)合分配的方向發(fā)展,傳統(tǒng)的資源分配策略無法直接應用到中繼網(wǎng)絡,且造成資源分配的算法復雜度和系統(tǒng)的信令開銷增大；另一方面,無線數(shù)據(jù)業(yè)務的快速增長和大量低功率中繼站點的引入使得系統(tǒng)功率消耗大大增加,基站能耗占所有設備能耗的一半以上,然而,過去大部分研究都是關注如何提高系統(tǒng)的吞吐率。隨著近年“綠色通信”的提出,如何在保證用戶服務質量(QoS)前提下,提高系統(tǒng)的能效,進而達到節(jié)能的目的,業(yè)已成為當前無線通信技術發(fā)展新的趨勢。為此,本文以基于OFDM/OFDMA技術的無線多跳中繼網(wǎng)絡為研究對象,以系統(tǒng)節(jié)能為主要目標,研究路徑選擇、分組調度和資源分配等無線資源管理關鍵技術。首先,針對放大轉發(fā)(AF)和解碼轉發(fā)(DF)的OFDM中繼系統(tǒng),分別提出一種能效最大化路徑選擇策略。針對三節(jié)點中繼OFDM網(wǎng)絡,在分析電路功率消耗、用戶速率需求、帶寬等因素在路徑選擇時對系統(tǒng)能效的影響基礎上,通過將中繼鏈路衰落值和直傳鏈路衰落值轉化為等效路徑損耗值,分別提出一種基于等效路徑損耗指數(shù)的能效最優(yōu)路徑選擇準則。分析結果表明,能效最優(yōu)傳輸路徑取決于用戶速率需求、鏈路信道條件以及系統(tǒng)帶寬等因素,并滿足本文所提出的能效最優(yōu)路徑判決準則。在此基礎上,將三節(jié)點DF中繼傳輸場景擴展到多用戶多中繼OFDMA蜂窩網(wǎng)下行傳輸系統(tǒng),考慮電路功率消耗和固定用戶速率需求的條件下,以能效最大化為目標,提出-種聯(lián)合路徑選擇、子載波和功率分配的低復雜度次優(yōu)算法。分析結果表明,與傳統(tǒng)路徑選擇策略相比,所提路徑選擇方案能夠顯著提升系統(tǒng)能效。其次,針對三節(jié)點DF模式中繼OFDM傳輸鏈路,提出一種系統(tǒng)總發(fā)射功率和用戶最小速率需求受約束條件下子載波配對和功率分配的能效最優(yōu)聯(lián)合優(yōu)化方案。該方案考慮了電路功率消耗對系統(tǒng)能效的影響,由于該問題屬于非凸優(yōu)化問題,直接求解復雜度高且難以實現(xiàn),為此,提出一種分情況討論求解策略,將非凸優(yōu)化問題轉化為凸優(yōu)化問題求解,并證明了系統(tǒng)能效最優(yōu)解的唯一性,再利用拉格朗日乘子法和KKT條件,通過注水算法獲得系統(tǒng)能效最優(yōu)解和功率分配結果。分析結果表明,與固定子載波配對能效最優(yōu)功率分配策略相比,所提方案可以進一步提升鏈路可達速率和能效性能；與傳統(tǒng)的速率最大化和功率最小化注水最優(yōu)算法相比,所提方案可以根據(jù)系統(tǒng)總發(fā)射功率和用戶速率需求約束條件自適應分配資源,以較低復雜度得到全局最優(yōu)解,保證鏈路傳輸?shù)目煽啃�。再�?考慮更為實際的源節(jié)點和中繼節(jié)點發(fā)射功率各自約束條件,提出一種子載波配對和功率分配的聯(lián)合優(yōu)化方案。該方案針對三節(jié)點DF模式中繼OFDM傳輸系統(tǒng),同時考慮電路功率消耗和用戶最小速率需求,以能效最大化為目標,建立聯(lián)合子載波配對和功率分配的優(yōu)化模型,采用分步求解策略,將非凸優(yōu)化問題轉化為凸優(yōu)化問題,利用注水策略獲得能效最優(yōu)解。分析結果表明,所提方案能夠在滿足各項約束條件情況下自適應分配資源,達到系統(tǒng)能效最優(yōu),同時還可以保證鏈路傳輸可靠性,降低鏈路的中斷概率和算法實現(xiàn)復雜度。接著,針對兩跳中繼OFDMA蜂窩網(wǎng)下行傳輸系統(tǒng),提出一種自適應關聯(lián)節(jié)能分組調度方案。該方案考慮不同類型業(yè)務QoS需求的差異性,用戶分組隊列狀態(tài),以及鏈路能效等綜合因素設計調度優(yōu)先級因子,在此基礎上,基于透明中繼傳輸場景,提出一種可以平衡接入域和透明域資源占用的比例的自適應分組調度策略,減少由于接入域和透明域的剩余資源比例失調而導致的中繼用戶分組數(shù)據(jù)無法及時調度的問題,進而提高系統(tǒng)時隙資源的利用率。分析結果表明,該方案能滿足不同類型業(yè)務QoS需求,保證用戶間的公平性；在保證系統(tǒng)吞吐量性能基礎上,進一步降低系統(tǒng)能耗。最后,針對兩跳中繼OFDMA蜂窩網(wǎng)下行傳輸系統(tǒng),提出一種半分布式自適應分組調度方案。該方案能夠區(qū)分實時(RT)和非實時(NRT)業(yè)務的QoS需求。為了保證實時業(yè)務的QoS需求和非實時業(yè)務獲得一定的受調度機會,該方案給出一種能區(qū)分業(yè)務類型的改進的比例公平分組調度優(yōu)先級因子設計方案；為了降低中繼傳輸系統(tǒng)的信令開銷,設計了一種自適應時隙重分配觸發(fā)機制,將BS和RS端定義的滿意度因子與給定的滿意度閾值進行比較,以決定是否觸發(fā)時隙重分配過程。一旦觸發(fā)時隙重分配,BS端調度器將根據(jù)BS端和各個RS端請求時隙數(shù)自適應調整BS和各個RS間的帶寬分配比例。分析結果表明,所提半分布式分組調度策略一方面可以提高系統(tǒng)吞吐量,滿足用戶的QoS需求,保證用戶間公平性,另一方面可以降低系統(tǒng)的信令開銷,有效降低中繼用戶切換丟包率。
[Abstract]:Orthogonal frequency division multiplexing (OFDM) / orthogonal frequency division multiplexing (OFDMA) and relay (Relay) multi hop relay networks have many advantages, such as high frequency spectrum efficiency, enhanced coverage, flexible networking and low network cost, which have become the mainstream architecture of the next generation of wireless networks recognized by the industry. Compared with traditional cellular networks, OFDM/OFDMA The environment of the relay network is more complex, which makes the problem of wireless resource management more challenging: on the one hand, the dimension of resource allocation is developed from the traditional time domain, frequency domain or space to multi-dimensional space. The traditional resource allocation strategy can not be directly applied to the relay network, and the allocation of resources is calculated. On the other hand, the rapid growth of wireless data services and the introduction of a large number of low power relay stations make the power consumption of the system greatly increased, and the energy consumption of the base station accounts for more than half of the energy consumption of all devices. However, most of the past studies are concerned about how to improve the throughput of the system. "Green communication" puts forward how to improve the energy efficiency of the system and achieve energy saving on the premise of guaranteeing the quality of user service (QoS), and it has become a new trend in the development of current wireless communication technology. Therefore, this paper takes the wireless multi hop relay network based on OFDM/OFDMA Technology as the research object, and studies the system energy saving as the main goal. The key technologies of wireless resource management are path selection, packet scheduling and resource allocation. Firstly, a path selection strategy for maximum energy efficiency is proposed for the OFDM relay system of amplified and forward (AF) and decode and forward (DF). For the three node relay OFDM network, the power consumption, user rate demand, bandwidth and other factors are analyzed in the path. On the basis of the influence of the selection on the energy efficiency of the system, the optimal path selection criterion based on the equivalent path loss index is proposed by converting the fading value of the relay link and the direct link fading value into the equivalent path loss value. The results show that the optimal transmission path of the energy efficiency depends on the user rate demand and link channel condition. On this basis, the three node DF relay transmission scene is extended to a multiuser and multi relay OFDMA cellular network downlink transmission system. Considering the power consumption of the circuit and the fixed user rate requirement, the energy efficiency maximization is taken as the goal, and the proposed approach is proposed. The analysis results show that the proposed path selection scheme can significantly improve the system energy efficiency compared with the traditional path selection strategy. Secondly, a constraint on the total transmission power and the minimum user rate requirement is proposed for the three node DF mode relay OFDM transmission link. This scheme considers the effect of power consumption on the energy efficiency of the system, which considers the effect of power consumption on the energy efficiency of the system. Because this problem belongs to the non convex optimization problem, it is difficult to solve the problem directly and it is difficult to realize. Therefore, a method of solving the problem is proposed and the non convex optimization problem is transformed into a convex optimization problem. The problem is solved, and the uniqueness of the system energy efficiency optimal solution is proved. By using the Lagrange multiplier method and the KKT condition, the system energy efficiency optimal solution and power allocation result are obtained by water injection algorithm. The analysis results show that the proposed scheme can further improve the link accessibility compared with the fixed sub carrier pairing energy efficiency optimal power allocation strategy. Rate and energy efficiency performance; compared with the traditional optimal rate maximization and power minimization injection optimization algorithm, the proposed scheme can allocate resources adaptively according to the system total transmission power and user rate requirements constraints, obtain the global optimal solution with lower complexity and ensure the reliability of link transmission. Again, consider more practical source nodes. A joint optimization scheme for seed carrier pairing and power allocation is proposed in this scheme. The scheme aims at the three node DF mode relay OFDM transmission system, taking into account the power consumption of the circuit and the minimum user rate requirement, aiming at maximizing the energy efficiency, and establishing the joint subcarrier pairing and power allocation. The optimization model, using the step solving strategy, transforms the non convex optimization problem into a convex optimization problem, and uses the water injection strategy to obtain the energy efficiency optimal solution. The analysis results show that the proposed scheme can allocate resources adaptively to meet the constraints of various conditions and achieve the optimal energy efficiency of the system. At the same time, the link transmission reliability can be guaranteed and the link can be reduced. The probability of interruption and the complexity of the algorithm are realized. Then, an adaptive association energy saving packet scheduling scheme is proposed for the downlink transmission system of two hop relay OFDMA cellular networks. This scheme takes into account the difference of QoS requirements of different types of services, the state of the packet queues, and the link energy efficiency to design the scheduling priority factors. Based on the transparent relay transmission scene, an adaptive packet scheduling strategy is proposed to balance the proportion of the resource occupancy of the access domain and the transparent domain, which reduces the delay of the packet data of the relay users due to the imbalance of the remaining resources in the access domain and the transparent domain, and thus improves the profit of the system time slot resources. The analysis results show that the scheme can meet the QoS requirements of different types of services and ensure fairness among users. On the basis of guaranteeing system throughput performance, the system energy consumption is further reduced. Finally, a semi distributed adaptive packet scheduling scheme is proposed for the downlink transmission system of two hop relay OFDMA cellular networks. QoS requirements for real-time (RT) and non real time (NRT) services. In order to ensure that the QoS requirements and non real time services of real time services are given a certain number of scheduling opportunities, the proposed scheme provides an improved proportional fair packet scheduling priority factor design scheme that distinguishes the service types from the traffic type, and designs the signaling overhead for reducing the relay transmission system. An adaptive time slot redistribution trigger is used to compare the satisfaction factor defined by the BS and the RS side with a given satisfaction threshold to determine whether to trigger the time slot redistribution process. Once the time slot redistribution is triggered, the BS end scheduler adaptively adjusts the bandwidth allocation ratio between the BS and each RS based on the BS end and each RS end request time slot number. The analysis results show that the proposed semi distributed packet scheduling strategy can improve the system throughput, meet the user's QoS requirements and ensure fairness among users. On the other hand, it can reduce the signaling overhead of the system and effectively reduce the packet loss rate of the relay users.
【學位授予單位】：西南交通大學
【學位級別】：博士
【學位授予年份】：2014
【分類號】：TN929.5

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本文編號：1909243