USSD - 百度百科
USSD
關鍵詞
非結構化補充數據業務USSD(Unstructured Supplementary Service Data)是一種基於全球移動通信系統GSM(Global System for Mobile Communications)網絡的、實時在線的新型交互會話數據業務；它基於用戶識別模塊 SIM(Subscriber Identity Module)卡，利用GSM網絡的信令通道傳送數據，是在GSM的短消息系統技術基礎上推出的新業務，在業務開拓方面的能力遠遠強於SMS系統。
USSD技術單獨使用或與短消息技術、 通用分組無線業務 GPRS(General Packet Radio Service)技術相結合，可為客戶提供種類繁多的增值業務，如移動銀行、金融股票交易、手機話費查詢、氣象信息預報和查詢、收發電子郵件、航班查詢、網上訂票、民意測驗等。 採用USSD對原有系統結構影響較小，且運營商還可以針對本地網的具體情況靈活地推出功能業務，方便地為移動用戶提供各類數據業務 ；另外USSD不僅可用於一些信息服務，利用移動運營商提供的通信網絡 ,也可應用於工業範圍，USSD的應用可使工業監控通信的範圍大大擴展，功能增強，成本降低，所以這種業務在香港特區、 新加坡等國家和地區已有廣泛的應用，在中國也有廣闊的應用前景。
相關比較
特點及與其他業務的比較
USSD系統與短消息業務SMS(Short Message Service)、GPRS和無線應用協議 WAP(Wireless Application Protocol)的應用範圍相似，但有其自己的特點。
USSD在通話狀態下
使用獨立專用控制信道SDCCH(Stand-alone Dedicated Control Channel), 數據傳輸速率大約為600bps;而非通話狀態時，USSD使用快速輔助控制信道FACCH(Fast Associated Control Channel),數據傳輸速率大約為1kbps,比SMS傳輸速率高。 用戶只能在非通話狀態下使用WAP,數據通過業務信道TCH(Traffic Channel)進行交換，其傳輸速率大約為9.6kbps，WAP的響應時間較慢，且需專門的WAP手機支持。
USSD在會話過程中
一直保持通話連接，提供透明通道 ,不進行存儲轉發 ；而SMS在物理承載層沒有會話通道，是一個存儲轉發系統，用戶完成一次查詢需要進行多次會話過程。 由於USSD與GPRS類似，在交互中保持一個會話過程，每次數據發送不需要重新建立信道，所以USSD系統對用戶的呼叫請求是即時響應，使響應時間大大加快，主要的響應時延已轉移為應用服務器一端，響應時間比短消息快。
USSD在交互式會話中
可以提供直觀的菜單操作，方便用戶使用，在一次信息服務中，只需要撥打服務號碼，以後就可以按菜單提示進行下一步操作，可以建立類似WAP的門戶網站來提供電信增值服務。
USSD和GPRS適合不同的用戶群
在工業環境下，在通信量不大、每次通信量只有幾K數據量的情況下使用USSD的費用低廉；而GPRS傳送帶寬高，適用於信息量大的數據傳輸。
市面上的手機大多支持USSD服務
在工業應用中，大多具有SMS和GPRS功能的通信模塊或芯片也支持USSD服務。
USSD在工業應用中的系統結構
如圖1,監控中心通過Internet或專線與USSD平台建立TCP/IP連接，USSD傳輸終端通過GSM的公用網絡與USSD平台建立無線連接，通過USSD平台與GSM網絡、監控中心和現場監控單元建立起一個數據通信的通道。在移動USSD平台中有數據庫備份數據，監控中心除應用平台外，還可備有有線瀏覽器進行監測。 透過GSM網絡和USSD平台，無線瀏覽器和手機也可與監控中心建立聯繫。
圖1 USSD系統結構圖
其中，USSD服務器有兩個網絡接口分別對應於歸屬位置寄存器 HLR(Home Location Register)和局域網：一方面，它通過七號信令 SS7(Signaling System No.7)的移動應用部分Map(Mobile Application Part )與GSM系統的HLR連接；另一方面，它通過專線以傳輸控制協議 /網際協議TCP/IP(Transfer Control Protocol/Internet Protocol)與應用監控中心連接。 應用監控中心與USSD服務器的接口協議可為短消息點對點 SMPP(Short Message Peer to Peer)或中國移動點對點CMPP(China Mobile Peer to Peer)。 GSM系統及USSD均起透明通道的作用， 監控中心可以發出指令，對終端或手機進行通信控製或發送短消息，手機或終端也可通過USSD服務來對監控中心發出請求以得到相應的服務。 通信通道建立之後，就可以像一般的工業總線一樣，監控中心對遠程終端進行三遙操作，終端也可以主動上報報警、開機等信息。
========================================================================
Unstructured Supplementary Service Data - Wikipedia
Unstructured Supplementary Service Data
Unstructured Supplementary Service Data (USSD) is a protocol used by GSM cellular telephones to communicate with the service provider's computers. USSD can be used forWAP browsing, prepaid callback service, mobile-money services, location-based content services, menu-based information services, and as part of configuring the phone on the network.[1]
USSD messages are up to 182 alphanumeric characters in length. Unlike Short Message Service (SMS) messages, USSD messages create a real-time connection during a USSD session. The connection remains open, allowing a two-way exchange of a sequence of data. This makes USSD more responsive than services that use SMS.[1]
Uses
When a user sends a message to the phone company network, it is received by a computer dedicated to USSD. The computer's response is sent back to the phone, generally in a basic format that can easily be seen on the phone display. Messages sent over USSD are not defined by any standardization body, so each network operator can implement whatever is most suitable for its customers.
USSD can be used to provide independent calling services such as a callback service (to reduce phone charges while roaming), enhance mobile marketing capabilities or interactive data services.
USSD is commonly used by prepaid GSM cellular phones to query the available balance. The vendor's "check balance" application hides the details of the USSD protocol from the user. On some pay as you go networks, such as Tesco Mobile, once a user performs an action that costs money, the user sees a USSD message with his new balance. USSD can also be used to refill the balance on the user's SIM card and to deliver one time passwords or PIN codes.
Some operators use USSD to provide access to real-time updates from social-networking websites like Facebook andTwitter.[2] Wikipedia uses USSD to send articles to some feature phones.[3]
USSD is sometimes used in conjunction with SMS. The user sends a request to the network via USSD, and the network replies with an acknowledgement of receipt:
- "Thank you, your message is being processed. A message will be sent to your phone."
Subsequently, one or more mobile terminated SMS messages communicate the status and/or results of the initial request.[4] In such cases, SMS is used to "push" a reply or updates to the handset when the network is ready to send them.[5] In contrast, USSD is used for command-and-control only.
Technical details
Most GSM phones have USSD capability.[6] USSD is generally associated with real-time or instant messaging services. There is no store-and-forward capability, as is typical of other short-message protocols like SMS. In other words, anSMSC is not present in the processing path.
USSD Phase 1, as specified in GSM 02.90, only supports mobile-initiated ("pull") operations.[7] In the core network, the message is delivered over MAP, USSD Phase 2, as specified in GSM 03.90.[8] After entering a USSD code on a GSMhandset, the reply from the GSM operator is displayed within a few seconds.
Format
A typical USSD message starts with an asterisk (*) followed by digits that comprise commands or data. Groups of digits may be separated by additional asterisks. The message is terminated with a number sign (#).[1]
USSD Mode
Mobile-initiated
- USSD/ PULL or USSD/ P2P
- when the user dials a code, e.g. *139# from a GSM mobile handset
Network-initiated
- USSD/ PUSH or USSD/A2P
- when the user receives a push message from the network; primarily used for promotional services
| Example USSD codes |
|---|
| *101# |
| *139*1*1234567890# |
This page was last modified on 31 October 2014 at 11:26.
========================================================================
沒有留言:
張貼留言