GPRS A/Gb 模式下的移动管理状态介绍 (A/Gb mode Mobility Ma...

移动开发:GPRS A/Gb 模式下的移动管理状态介绍 (A/Gb mode Mobility Management States)
[ 来源：移动开发 | 作者：移动开发 | 时间：2007-7-20 | 去论坛]                                    --
 A/Gb mode Mobility Management States
A/Gb 模式下的 GPRS 移动管理状态介绍
1.IDLE State
In GPRS IDLE state,the subscriber is not attached to GPRS mobility management,The MS and SGSN contexts hold no valid location or routing information for the subscriber.The subscriber-related mobility management procedures is not performed.The MS performs PLMN selection and cell selectiong and re-selection.
Data transmission to and from the mobile subscriber as well as the paging of the subscriber is not possible.The GPRS MS is seen as not reachable in this case.
In order to establish MM contexts in the MS and the SGSN,the MS shall perform the GPRS attach procedure.空闲状态
在GPRS 空间状态,签约者没附着到GPRS移动管理,在移动台和GPRS 服务支撑节点的上下文中没有签约者
有效的位置和路由信息.签约者相关的移动管理规程没有被执行.移动台执行公共陆地移动网络的选择、小区的选择和重选。移动台不能接收和发送数据，也不能寻呼。
在该状态下的移动台被认为是不可到达的，为了在移动台和GPRS服务支撑节点中建立移动管理上下文，
移动台需要执行GPRS附着规程。 2.STANDBY State
  In STANDBY state,the subscriber is attached to GPRS mobility management.The MS and SGSN have established MM contexts .Pages for data or signalling information transfers may be received.It is also possible to receive pages for the CS services via the SGSN.Data reception and transmission are not possible in this state.The MS performs GPRS Routing Area(RA) and GPRS cell selection and re-selection locally.The MS executes mobility management procedures to inform the SGSN when it has entered a new RA.The MS does not inform the SGSN on a change of cell in the same RA.Therefore,the location information in the SGSN MM context contains only the GPRS RAI for MSs in STANDBY state.The MS may initiate activation or deactivation of PDP contexts while in STANDBY state.A PDP context shall be activated before data can be transmitted or received for this PDP context.The SGSN may have to send data or signalling information to an MS in STANDBY state.The SGSN then sends a Paging Request in the routing area where the MS is located if PPF is set.If PPF is cleared,then paging is not done.The MM state in the MS is changed to READY when the MS responds to the page,and in the SGSN when the page response is received.Also,欢迎光临学网,收藏本篇文章 [1] [2] [3]$False$the MM state in the MS is changed to READY when data or signalling infomation is send from the MS and,accordingly,the MM state in the SGSN is changed to READY when data or signalling information is received from the MS.The MS or the network may initiate the GPRS Detach procedure to move to the IDLE state.After expiry of the mobile reachable timer the SGSN may perform an implicit detach in order to return the MM contexts in the SGSN to IDLE state.The MM and PDP contexts may then be deleted.守侯状态
在守侯状态下，签约者已经附着到了GPRS 移动管理。在移动台和SNGN 中已经建立起了移动管理上下文。
为传输数据和信令而发起的寻呼可以被接收。也可以接收经由SGSN来自电路域的寻呼。在该状态下不能够发送和接收数据。移动台可以进行路由区和小区的选择和重选。当移动台进入新的路由区，将执行移动管理规程来通知对应的SGSN，但在同一路由区内小区的变化信息不会通知SGSN，因此在守侯状态下，在SGSN 的移动管理上下文中只保存有移动台的GPRS 路由区标识的位置信息。在守侯状态下，移动台可以发起分组数据协议上下文的激活和去激活。在发送和接收数据之前必须激活对应的分组数据协议上下文。SGSN 可以向处于守侯状态的移动台发送数据和信令信息。如果寻呼过程标记（Paging Proceed Flag）已经被设置，SGSN 首先要对移动台所在的路由区发起寻呼请求。如果寻呼过程标记已经被清除，则不能发起寻呼。
如果移动台对寻呼进行响应，则移动台状态转变为就绪状态，并且当SGSN接收到给响应后，在该SGSN 中的移动台的移动管理状态转变为就绪状态。
如果移动台发送数据和信令，在移动台状态也将转变为就绪状态。
如果SNSN接收到书决和信令，则SGSN的状态也将转变为就绪状态。3.READY State
 In READY state,the SGSN MM context corresponds to the STANDBY MM context extended by location information for the subscriber on the cell level.The MS performs mobility management procedures to provide the network with the actual selected cell.GPRS cell selection and re-selection is done locally by the MS,or may optionally be controlled by the network.An identifier of the cell, the Cell Global Identity including RAC and LAC,is included in the BSSGP header of the data packet from the MS.The MS may send and receive PDP PDUs in this state.The network initiates no GPRS pages for an MS in READY state.Pages for other services may be done via the SGSN.The SGSN transfers downlink data to the BSS responsible for the subscriber's actual GPRS cell.The MS may activate or deactivate PDP contexts while in READY state.
Regardless if a radio resource is allocated to the subscriber or not,the MM context remains in the READY state even when there is no data being communicated.A timer supervises the READY state.An MM context moves from READY state to STANDBY state when the READY timer expires.In order to move from READY state to IDLE state,欢迎光临学网,点击这里查看更多文章教程 [1] [2] [3] the MS initiates the GPRS Detach procedure.就绪状态
在就绪状态下，SGSN 中的移动管理上下文中相对与守侯状态下的移动管理上下文扩展了签约者所在小区的位置信息。移动台通过执行移动管理规程向网络侧提供精确的小区。GPRS 小区的选择和重选可以由移动台本地完成也可以由网络侧控制。小区标识即小区全球标识，包含路由区编码和位置区编码，该标识被包含在来自移动台数据分组的基站系统GPRS协议头中。在就绪状态下，移动台可以发送和接收分组数据协议分组数据单元。网络侧不会向处于就绪状态的移动台发起寻呼。对其他服务的寻呼经由SGSN 完成。SGSN 传输下行链路数据给负责签约者所在小区的基站系统。在就绪状态下，移动台可以激活或去激活分组数据协议上下文。当没有数据传输时，无论签约者是否被分配了无线资源，移动管理上下文都将处于就绪状态。就绪状态由一个定时器来管理。当就绪定时器超时，移动管理上下文由就绪状态转变为守侯状态。如果要将移动管理状态由就绪状态转变为空闲状态，则需要移动台发起GPRS 分离规程。   
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