Nist wimax module
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NIST WiMAX Module. 徐士欽. Introduction. 美國國家標準技術局 (National Institute of Standards and Technology, NIST) 經過 NS-2 官方網站一連串的相關測試成為內建模組 IEEE 802.16e 延伸,支援掃描與換手 我可以用這個模組做些什麼 ?. Overview. Try First !. The example “test-be.tcl” in /ns-allinone-2.29/ns-2.29/tcl/wimax. 要做什麼 ?. 到底要怎麼用 ?

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NIST WiMAX Module

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NIST WiMAX Module

徐士欽


Introduction

  • 美國國家標準技術局(National Institute of Standards and Technology, NIST)

  • 經過NS-2官方網站一連串的相關測試成為內建模組

  • IEEE 802.16e延伸,支援掃描與換手

  • 我可以用這個模組做些什麼?


Overview


Try First !

  • The example “test-be.tcl” in

    /ns-allinone-2.29/ns-2.29/tcl/wimax


要做什麼?

  • 到底要怎麼用?

  • 跟普通的有什麼不一樣?

  • 來看看TCL吧!


還記得什麼??

  • 設定WiMAX基本參數 RTG、TTG、、等

  • 設定PHY為OFDM!

  • 設定涵蓋範圍

  • 設定Mobile node config (OPT系列),尤其是MAC!

  • 初始化BS位置,設定node

  • 初始化SS位置,設定與BS相依

  • 設定DIUC


幾個小問題

  • 怎麼都沒看到mobile node?

  • Create God ?

    • Storing connectivity information of the topology.

    • http://0rz.tw/df3cX

  • set opt(adhocRouting) DSDV

    • 可以不設嗎?

    • 有哪些選擇?

    • DSDV、DSR、AODV和TORA


本週小練習

  • 請改寫test-be.tcl使得無法在NAM上顯示所有定義的mobile node的問題得以解決。

  • 請至少能顯示10個nodes

  • 相對的,完成此作業的前提是要安裝成功NIST的module


再深入一點

  • MAC層模組架構

    • Mac802_16(Class)繼承NS-2原有的Mac類別,負責處理封包的傳送與接收 。

  • Frame structure

    • Time Division Duplex, TDD

    • Uplink & Downlink

  • IEEE 802.16e

    • Scanning

    • Handoff 


MAC module structure


幾個重要的元件

  • ServiceFlowHandler is responsible for handling flow requests/responses. It also stores the list of flows for the node.

  • The class PeerNode contains information about the peer, such as its connections and status.

  • ConnectionManager contains the list of incoming and outgoing connections.


更多的重要元件

  • The WimaxScheduler abstract class is used to create an interface with the MAC. (SS & BS)

  • StatWatch and ThroughputWatch objects for packet and traffic information. The values are used to trigger events


MAC802_16 內容貌似很重要!


封包資訊都藏在哪裡?

  • /ns-allinone-2.29/ns-2.29/wimax/mac802_16.cc


Header裡的重要資訊

  • A virtual physical header of type phy_info_t. This structure is used to carry physical information

  • A generic MAC header of type gen_mac_header_t containing the generic MAC information.


Scheduler

  • The class structure allows for specifying different data services namely UGS, rtPS, nrTPS, and Best Effort. The services are specified in the ServiceFlow class.

  • BS scheduler & SS scheduler.


Packet Processing Flow


classifier


緊緊相依 相互影響

  • MAP:描述頻寬分配後的結果,SS需在指定的時間傳送或接收資料

  • 對進入的封包做Service flow 的QoS設置

  • BS Scheduler的運作機制

  • SS Scheduler的運作機制


QoS & Service Flow

  • The framework defines structures to support the implementation of schedulers that make use of the different classes of service.

  • Each Connection can be associated with a ServiceFlow and corresponding QoS parameters.


Service Flow如何被實現

ns-allinone-2.29/ns-2.29/wimax


空歡喜

  • QoS尚未被實作,空殼定義

  • 只有BE被實作

  • NO Admission control !

    • It accepts all the flow request from the MSs.

  • 真遺憾,那我們還能做些什麼??

    • TCL commands


TCL Command

  • Replace the default service flow handler.

  • The parameters are as follows:

  • DL – Downlink, use UL for Uplink

  • 10000 – Data Rate (byte/s)

  • BE - Scheduling Type BE/rtPS/nrtPS/ertPS

  • 700 – Datasize (byte)

  • 2 – Period (For UGS traffic)

  • 1 - To indicate if ARQ is enabled or not

  • 0.01 - ARQ Retransmission timer value (s)

  • 8 - ARQ Window size

  • 1 - counter to indicate when ARQ ACKs have to be sent

  • Configure the list of flows that must be setup after network entry.

mac set-servicehandler FlowHandler

[$wl_node_($i) set mac_(0)] setflow DL 10000 BE 700 2 1 0.01 8 1


Schedulers (cont.)

  • In IEEE 802.16, the BS controls the bandwidth allocation.

  • The model includes an abstract class, WimaxScheduler, created to easily use different packet schedulers.

  • This class already contains two implementations, an SSscheduler for SSs and a BSscheduler for BSs.


彈性的架構設計

ns-allinone-2.29/ns-2.29/wimax/scheduling


我想自己做scheduler!

  • init (): initialize the scheduler.

  • process (Packet *):

    • This method is used to process packets received by the scheduler (such as synchronization messages).

  • start_ulsubframe ():

    • code to be executed at the beginning of a new uplink subframe.

  • start_dlsubframe ():

    • code to be executed at the beginning of a new downlink subframe.


BS Scheduler TCL command

  • set scheduler [new WimaxScheduler/BS]

    • Creates a packet scheduler for BS.

  • $scheduler set-contention-size $size

    • Set the number of contention slots to be allocated for initial ranging and bandwidth requests in each frame.

  • WimaxScheduler/BS set dlratio_ 0.3

    • Indicates 30% of the frame is for downlink and 70% is for uplink.


SS Scheduler TCL command

  • set scheduler [new WimaxScheduler/SS]

    • Creates a packet scheduler for SS.


DIUC / UIUC


怎麼設定調變

  • [$SSWithWiMax set mac_(0)] set-diuc 7

    • The user can select the burst profile to use [1-7] by TCL.

  • Note:

    By default, the profile (modulation) is the same for BOTH downlink and uplink for communication between an SS and a BS.


設定scheduler與節點的連結

  • # Add scheduler

  • [$nodeWithWiMax set mac_(0)] set-scheduler $scheduler


D/UIUC會不會被調整?

  • Currently there is no algorithm implemented to make use of the ranging capabilities. It is used to add additional latency to the network entry. Periodic ranging and CDMA request are also not implemented.


謝謝

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