IEEE 802.16 Mesh networks排程控制訊息成本之效能分析

Signaling Cost Evaluation in IEEE 802.16 Mesh Networks

陳子宏(Zih-Hong Chen)

指導教授 ： 楊峻權

國立暨南國際大學/科技學院/資訊工程學系/碩士(2007年)

https://doi.org/10.6837/NCNU.2007.00206

摘要

IEEE 802.16寬頻無線網路技術在近幾年來成為網路研究上熱門的研究技術，IEEE 802.16和以往無線路技術不同的地方是在於它為網路佈建上最後一哩(由骨幹網路連接到用戶端)提供了一個更快更便利的解決方案，也因此被定位成都會型無線網路(Wireless Metropolitan Area Network)。在IEEE 802.16-2004標準中，主要著重在於固定的網路存取點，並且提供最高到75Mbps的連線速度，而最近在IEEE 802.16e標準中更是把目標放在行動管理上，以因應使用者可以移動的情況。
在IEEE 802.16的標準中，訂定了兩種網路連線架構，一種是在802.16網路中，所有subscribe stations (SSs)都只能直接連線到base station (BS)上的PMP架構，另一種則是SS跟SS可以互相連接，透過hop-by-hop的方式一直relay資源到目的地的Mesh架構。而在Mesh架構中又訂定出兩種不同的排程方式(scheduling)，分別是集中式排程和分散式排程，在集中式排程中，所有的頻寬分配、排程等工作都是由BS負責完成，且在資料傳輸路徑上，資料都必須先往BS送，再由BS傳送到目的端：在分散式排程中，不像集中式排程有BS可統一管理資源的設備，而是透過由各個SS交換資訊以取得傳輸時機的機制。另外我們在過去也提出一種IEEE 802.16 Mesh下的集中式排程機制，和IEEE 802.16標準上的集中式排程機制主要不同的地方是在於路徑的選擇上，在我們所提出的架構中，資料傳輸的路徑可以直接由source到destination中。如此一來，資料傳輸不需要再經過BS，以較短的路徑傳送，且也不會有在分散式排程中SS必須彼此相互競爭所帶來的負擔。
在本篇論文中，主要是探討在IEEE 802.16的Mesh架構中，以控制訊息成本的角度而言，不同的排程機制在資料傳輸過程時在各種不同的網路狀態中對網路帶來的負擔、以及對效能上的影響為何，我們分別對以上三種的排程機制做了分析以及模擬測試，藉以比較三種排程間的差異。

關鍵字

訊號成本 ； IEEE 802.16 Mesh ； 集中式排程 ； 分散式排程

並列摘要

Broadband Wireless Access (BWA) technology is aiming to provide an easy, time-saving, and low-cost method for deployment of next generation network infrastructure. Since 1998, IEEE 802.16 working group has launched a standardization process call Wireless Metropolitan Area network (Wireless MANTM) for BWA. The newly released specification of 802.16 (IEEE Std 802.16-2004)[1] focuses on fixed location wireless access and can support up to 75bps bit rate.
There are two mechanisms to schedule data transmission in the IEEE 802.16 Mesh networks: centralized and distributed scheduling. In the centralized scheduling scheme, the BS works like the cluster head and determines time slot allocation of each SS. In order to transmit data packets, the SS is required to submit the request packet to the BS via the control channel. The BS grants the access request by sending the slot allocation schedule call UP_MAP to all SS nodes. In the distributed scheduling scheme, if the SS have data to send, it need to compete with it neighbors. So that it can start data transmission.
We’ve proposed a combinational framework in previous works[17], it combine the two advantages of centralized scheduling and distributed scheduling. It has centralized controller BS and it can select a shortest path between source SS and destination SS.
In this thesis, we discussed the signaling cost in those two different scheduling schemes of IEEE 802.16 Mesh network and our previous works. We analyzed the effect factors on signaling cost. We also proposed a simple theoretical model in centralized scheduling and proposed framework. In the rest of this thesis, we simulated some scenarios to show those three scheme’s differences.

並列關鍵字

signaling cost ； IEEE 802.16 Mesh ； centralized scheduling ； distributed scheduling

參考文獻

[1] IEEE Std. 802.16-2004, “IEEE Standard for Local and metropolitan area networks—Part 16: Air Interface for Fixed Broadband Wireless Access Systems,” Oct. 2004.

[2] IEEE Std. 802.16e-2005, “IEEE Standard for Local and metropolitan area networks--Part 16: Air Interface for Fixed Broadband Wireless Access Systems—Amendment 2: Physical and Medium Access Control Layers for Combined Fixed and Mobile Operation in Licensed Bands,” Feb. 2006.

[3] IEEE Std. 802.11a, ”Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications: Higher Speed Physical Layer in the 5GHz band,” Sept. 1999.

[4] IEEE Std. 802.11b, ”Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications: Higher Speed Physical Layer in the 2.4GHz band,” Sept. 1999.

[5] IEEE Std. 802.11g,”Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications: Higher Speed Physical Layer in the 2.4GHz band,” Jun. 2003.