CCPCH
Encyclopedia
CCPCH stands for Common Control Physical CHannel in UMTS and some other CDMA communications systems. It is a broadcast radio channel by which a mobile phone
or User equipment can decode and determine important system parameters before establishing a dedicated communications link.
In a FDD
UMTS system, there are two CCPCH- Primary and Secondary. Exactly one Primary-CCPCH, which has a data rate of 27kbit/s and is always broadcast using Channelisation Code Cch,256,1. This channel can be detected by mobiles due to its fixed channelisation code, slot format and TTI
, as well as being time aligned to the Synchronisation Channel which replaces the first 2 bits of P-CCPCH in every slot. The Broadcast Control Channel (BCH) transport channel is mapped onto the P-CCPCH, allowing mobiles to decode important system parameters prior to establishing a dedicated connection. One or more Secondary-CCPCHs are also provided to broadcast paging blocks and FACH messages.
The P-CCPCH in a TDD
-mode UMTS system also carries pilot bits in (in contract to FDD
-mode which provides a distinct pilot channel named CPICH
). The pilot bits on the CCPCH can be used for measurements of the signal quality (e.g. RSCP
, Ec/Io, etc.) and for synchronisation and timing reference when decoding other channels from the same transmitter.
Mobile phone
A mobile phone is a device which can make and receive telephone calls over a radio link whilst moving around a wide geographic area. It does so by connecting to a cellular network provided by a mobile network operator...
or User equipment can decode and determine important system parameters before establishing a dedicated communications link.
In a FDD
Duplex (telecommunications)
A duplex communication system is a system composed of two connected parties or devices that can communicate with one another in both directions. The term multiplexing is used when describing communication between more than two parties or devices....
UMTS system, there are two CCPCH- Primary and Secondary. Exactly one Primary-CCPCH, which has a data rate of 27kbit/s and is always broadcast using Channelisation Code Cch,256,1. This channel can be detected by mobiles due to its fixed channelisation code, slot format and TTI
Transmission Time Interval
TTI, Transmission Time Interval, is a parameter in UMTS related to encapsulation of data from higher layers into frames for transmission on the radio link layer. TTI refers to the duration of a transmission on the radio link...
, as well as being time aligned to the Synchronisation Channel which replaces the first 2 bits of P-CCPCH in every slot. The Broadcast Control Channel (BCH) transport channel is mapped onto the P-CCPCH, allowing mobiles to decode important system parameters prior to establishing a dedicated connection. One or more Secondary-CCPCHs are also provided to broadcast paging blocks and FACH messages.
The P-CCPCH in a TDD
Duplex (telecommunications)
A duplex communication system is a system composed of two connected parties or devices that can communicate with one another in both directions. The term multiplexing is used when describing communication between more than two parties or devices....
-mode UMTS system also carries pilot bits in (in contract to FDD
Duplex (telecommunications)
A duplex communication system is a system composed of two connected parties or devices that can communicate with one another in both directions. The term multiplexing is used when describing communication between more than two parties or devices....
-mode which provides a distinct pilot channel named CPICH
CPICH
CPICH stands for Common Pilot Indicator CHannel in UMTS and some other CDMA communications systems.In WCDMA FDD cellular systems, CPICH is a downlink channel broadcast by Node Bs with constant power and of a known bit sequence. Its power is usually between 5% and 15% of the total Node B transmit...
). The pilot bits on the CCPCH can be used for measurements of the signal quality (e.g. RSCP
RSCP
In the UMTS cellular communication system, received signal code power denotes the power measured by a receiver on a particular physical communication channel. It is used as an indication of signal strength, as a handover criterion, in downlink power control, and to calculate path loss...
, Ec/Io, etc.) and for synchronisation and timing reference when decoding other channels from the same transmitter.