Abstract
The divided-layer protocol architecture for Mobile ad hoc Networks(simply MANETs)can only provide partial stack. This leads to treat difficulties in QoS guarantee of multimedia information transmission in MANETs, this paper proposes Across-layers QoS Model for MANETs, CQMM. In CQMM ,a core component was added network status repository(NSR), which was the center of information exchange and share among different protocol layers in the stack. At the same time,CQMM carried out all kinds of unified QoS controls. It is advantageous that CQMM avoids redundancy functions among the different protocol layers in the stack and performs effective QoS controls and overall improvements on the network performances.
Keyword Cross-layers QoS Model, Mobile Ad hoc Networks(MANETs);Network Status Repository(NSR) QoS Controls.
1 introduction
With the rapid development of multimedia technologies and the great increase of he bandwidth for personal communication,video and Video services begin to be deployed in MANETs. Different from static networks and Internet,multimedia communications in MANETs such as Voice and Video services require strict QoS guarantee, especially the delay guarantee. In addition, communication among different users can be integrated services with different QoS requirements. These lead to great challenges in QoS guarantee of multimedia communication in MANETs. There are two main reasons in these: 1)MANETs runs in atypical wireless environment with time-varying and unreliable physical link, broadcast channel, and dynamic and limited bandwidth and so forth. Therefore, it can only provide limited capability for differentiated services with strict QoS requirements [1].2) It is difficult that traditional flow project and access control mechanism are implemented because of mobility, multiple hops and self-organization of MANETs.
At present, most researches on QoS based on traditional divided-layer protocol architecture for MANETs focus on MAC protocol supporting QoS[2],QoS routing protocol [3] and adaptive application layer protocol with QoS support[4], and so on. It is avoidless that there will be some redundancies on functions among the different protocol layers in the stack. This will increase the complexity of QoS implementation and cause some difficulties in overall improvement on the network performances. Therefore, it is not suitable for MANETs with low processing ability
In recent years, the cross-layers design based on the partial protocol layers in MANETs was put forward.[1] proposed the mechanism with QoS guarantee for heterogeneous flow MAC layer.[5,6,7,8] did some researches on implementing video communication with QoS guarantee by exchange and cooperation of information among a few layers in MANETs. These can improve QoS in MANETs’ communication to some extent. However, MANETs is much more complex than wired system and static network, and improvements on QoS guarantee depend on full cooperation among all layers in the protocol stack. Therefore, it is difficult for the design to provide efficient QoS guarantee for communication and overall improvements on the network performances in MANETs.
To make good use of limited resources and optimize overall performances in MANETs, this paper proposes a novel cross-layer QoS model, CQMM, where different layers can exchange information fully and unified QoS managements and controls can be performed.
The rest of the paper is organized as follows. CQMM is described in section 2 in detail. In section 3,we analyze CQMM by the comparison with DQMM..The section 4 concludes the paper.


摘要

分層協(xié)議的體系結(jié)構(gòu)只能為移動Ad Hoc網(wǎng)絡(luò)（簡稱MANETs ）提供部分堆棧。這給移動Ad Hoc網(wǎng)絡(luò)中的多媒體通信的質(zhì)量保證帶來了很大的困難。為了改進(jìn)移動Ad Hoc網(wǎng)絡(luò)中的多媒體信息傳輸?shù)姆?wù)質(zhì)量，本文將介紹一種針對移動Ad Hoc網(wǎng)絡(luò)的跨層服務(wù)質(zhì)量模型—-CQMM。CQMM的一個核心組件是網(wǎng)絡(luò)狀態(tài)儲存庫(NSR)，它是信息交換的中心，而且能在堆棧中的不同協(xié)議層之間共享。同時，CQMM能夠?qū)崿F(xiàn)所有標(biāo)準(zhǔn)的QoS 控制。另外，CQMM還能消除堆棧中不同協(xié)議層之間的冗余功能，并有效的執(zhí)行QoS控制和網(wǎng)絡(luò)性能的全面改善。

關(guān)鍵字 跨層QoS模型，移動Ad Hoc網(wǎng)絡(luò)（MANETs） ，網(wǎng)絡(luò)狀態(tài)儲存庫（NSR），QoS控制。

1、 引言
隨著多媒體技術(shù)的快速發(fā)展，和個人通信帶寬的增加，音頻和視頻服務(wù)已開始在MANETs中出現(xiàn)。與靜態(tài)網(wǎng)絡(luò)和因特網(wǎng)不同的是，MANETs中的多媒體通信，如音頻和視頻服務(wù)，它們對QoS的保證有非常嚴(yán)的要求，特別是延遲的保證。此外，具有不同QoS要求用戶之間的通信可以集成服務(wù)。這給MANETs.多媒體通信的QoS保證提出了很大的挑戰(zhàn)。主要有兩個原因：1 ）MANETs是在一種傳統(tǒng)的無線環(huán)境下運(yùn)行的，即，該環(huán)境隨時間而變化，具有不可靠的物理鏈接、廣播頻道和動態(tài)的有限的帶寬，等等。因此，它只能為有嚴(yán)格QoS要求的被區(qū)分的服務(wù)提供有限的能力 [ 1 ]. 2 ）由于MANETs的靈活性，多級跳以及自組性，因而，傳 統(tǒng) 的流動項(xiàng)目和訪問控制機(jī)制就非常難以實(shí)現(xiàn)。

目前，我國大部分基于MANETs傳統(tǒng)的多層協(xié)議結(jié)構(gòu)的QoS研究都側(cè)重于支持QoS [ 2 ]的MAC協(xié)議， QoS路由協(xié)議[ 3 ]和與QoS支持[ 4 ]適應(yīng)的應(yīng)用層協(xié)議，等等。但，這無法避免堆棧中不..