A qos - support protocol , m - dcf , and its schedule model are proposed . by providing different contention window for different classes , the higher class frames the higher access probability . the simulation proves that m - dcf has better performance than dcf protocol on system throughput , discard ratio , frame discard ratio of higher classes , average access delay of different classes 提出了為不同等級幀提供不同競爭窗口的改進型dcf : m - dcf協(xié)議,并給出了m - dcf的調(diào)度模型,通過采用不同的競爭窗口,為不同n西安電子科技大學博士學位論文:無線局域網(wǎng)和ip服務(wù)質(zhì)量關(guān)鍵技術(shù)的研究的應(yīng)用提供了不同的接入概率,保證了qos ;仿真結(jié)果證明了m一dcf在系統(tǒng)吞吐率、丟包率、高等級業(yè)務(wù)丟包率、不同等級業(yè)務(wù)的平均接入時延等方面都優(yōu)于dcf協(xié)議。
The research on df ( decode - and - forword ) cooperation scheme is proposed aferwrds by analysis and simulation , compared with the af scheme in performance and application . at last after research on cc ( coded cooperation ) cooperation scheme , including original cc and space - time cc , an adaptive space - time coded cooperation scheme , which could more efficiently ultilize the resource of cooperation users , is propsed . simulation results have proved the proposed scheme has better performance than space - time cc both in bit error rate and system throughput 最后在對編碼前傳( cc , codedcooperation )協(xié)同分集方式中的普通編碼協(xié)同和空時編碼協(xié)同的原理和實現(xiàn)方式進行研究的基礎(chǔ)上提出了一種基于空時編碼協(xié)同的對信道具有自適應(yīng)能力的自適應(yīng)空時編碼協(xié)同方法,并分析了這種方法的優(yōu)越性,通過計算機仿真證明了新方法帶來的誤碼率性能的改善和系統(tǒng)吞吐量的提升。
The characteristics of the data schedule arithmetic on forward link is that , considering fair , the system provides service for the user who applies the highest data rate , in order to increase the system throughput on the forward link . the characteristics of the data rate control arithmetic on reverse link is that , under the condition of ensuring reverse power unoverload , the system controls users to transmit data rate as high as they can to communicate with base station , in order to increase the system throughput on the reverse link 前向數(shù)據(jù)調(diào)度算法的特點在于:在兼顧公平性的基礎(chǔ)上,系統(tǒng)盡量為申請速率最大的用戶服務(wù),以此來提高系統(tǒng)的前向鏈路數(shù)據(jù)吞吐量;反向數(shù)據(jù)速率控制算法的特點在于:在保證反向功率不過載的情況下,系統(tǒng)控制用戶盡可能的提高發(fā)射速率來和基站通信,以此來提高系統(tǒng)的反向鏈路數(shù)據(jù)吞吐量。
Then an lqocm linear quadratic optimal control model is presented . finally , experiments demonstrate that , for the end - to - end drts whose control matrix - pmb g falls into the stable region , the ic - eat is convergent and stable . moreover , it is capable of providing better qos guarantees for end - to - end aperiodic tasks and improving the system throughput 在這之中,一部分系統(tǒng)常常運行于動態(tài)與不確定環(huán)境,比如:在一個自動監(jiān)控系統(tǒng)中,被監(jiān)控目標數(shù)的動態(tài)變化使得系統(tǒng)中任務(wù)的到達與離開呈現(xiàn)出非周期性此外,任務(wù)的執(zhí)行時間也隨著系統(tǒng)任務(wù)數(shù)目標距控制中心距離的變化而變化。