RRC State Change refers to the process of switching between these states. Roughly there are three different stages (DCH, FACH, PCH).. but in more detail you can classify them into four different stages as shown below.

The Radio Resource Control (RRC) protocol is used in UMTS, LTE and 5G on the Air interface. It is a layer 3 (Network Layer) protocol used between UE and Base Station. This protocol is specified by 3GPP in TS 25.331 [2] for UMTS, in TS 36.331 [3] for LTE and in TS 38.331 [4] for 5G New Radio. RRC messages are transported via the PDCP-Protocol.

In LTE, the RRC_CONNECTED state has the benefits of CELL_FACH and to some extent CELL_PCH incorporated in it. Since in the downlink the scarce resource is the resource blocks, the downlink logical channels are always mapped onto shared transport channels (exhibiting the CELL_FACH properties).

FACH requires an RRC connection to the RNC and minimizes use of radio resources by utilizing a slow speed shared channel with a bandwidth limited to aprox-imately 32 kbps. FACH has lower device energy con-sumption than DCH, and FACH to DCH promotions require less signaling overhead than IDLE to DCH pro-motions.

2015年3月18日 · 从技术的角度看，我们把这叫rrc状态。wcdma有5种状态：idle，cell_fach，cell_dch，cell_pch和ura_pch。idle状态表示手机空闲；cell_dch状态表示手机正在执行任务，比如上网看视频；cell_fach状态表示手机正在执行一些少量任务。

2019年8月8日 · rrc连接释放只能发生在cell_dch或cell_fach状态下，如果当前rrc连接处于cell_pch或者ura_pch状态，utran先发起寻呼将ue状态迁移到cell_fach，再进行rrc连接释放。 rnc根据不同情况，在下行dcch或ccch上通过um rlc方式发送rrc连接释放消息rrc connection release。

2018年8月24日 · rrc 层：作为整个 lte 系统的控制实体，完成了包括系统信息广播，寻呼，rrc 连接建立、释放、配置、重建立，无线承载的管理，信令消息的加密与安全控制，切换与测量上报等功能。

This page covers WCDMA UE RRC layer and explain RRC state diagram. It covers WCDMA RRC states idle and connected mode as per UMTS standard.There are cell_DCH, cell_FACH, cell_PCH and URA_PCH states when UE is in connected mode.

2023年3月4日 · 参考TS 25.331，从NAS层的角度来看，UE可以处于空闲模式或连接模式，因此连接模式包括另外四种不同的RRC状态：URA_PCH、CELL_PCH、CellL_FACH和CELL_DCH。 当准确的RRC状态不重要时，这种方法允许区分IDLE和CONNECTED模式，但更重要的是强调UE具有AS上下文。 同时，可以参考特定RRC状态，例如CELL_DCH。 对于NR系统，可能会出现与UMTS中完全相同的术语问题：有时需要指示UE处于CONNECTED模式，这意味着它具有as …

2018年8月24日 · rrc 层：作为整个 lte 系统的控制实体，完成了包括系统信息广播，寻呼，rrc 连接建立、释放、配置、重建立，无线承载的管理，信令消息的加密与安全控制，切换与测量上报等功能。