A conventional cellular system is operated by fixedly allocating a transport channel and a physical channel for paging information. In particular, in a 3rd Generation Partnership Project (3GPP) system of a Wideband Code Division Multiple Access (WCDMA) method, a paging channel (PCH) is a transport channel and is transmitted through a secondary common control physical channel (S-CCPCH), which is a physical layer channel for transmitting common control information. A forward access channel (FACH), which is a transport channel having a similar attribute to the paging channel, and a paging channel can be mapped to the S-CCPCH.
In a conventional WCDMA system, a radio resource is assigned by allocating a code index of orthogonal variable spreading factor (OVSF) with orthogonality. Therefore, an individual OVSF code index is allocated to the S-CCPCH and another physical layer channel may not use or share the OVSF code index allocated to the S-CCPCH. Although there is no information to be transmitted from a base station to a terminal through the transport channel PCH and FACH at a given time, the physical layer channel S-CCPCH exists. Although there is no transmitted information in the S-CCPCH, the OVSF code index and another radio resource, i.e., power, are allocated and thus radio resources are wasted.
A general paging procedure is as follows. Terminals are included in a specific paging group defined for an efficient paging procedure in a system. Therefore, the base station notifies that a paging message arrives at terminals included in a corresponding group through the paging indication channel (PICH), which is a physical layer channel. The terminals monitor the paging indication channel every monitoring cycle. As a result of monitoring, when it is sensed that indication information corresponding to the group including the terminal exists in the paging indication channel, the terminals search PCH information transmitted to the S-CCPCH channel and decode paging information that an identifier (ID) such as international mobile subscriber identity (IMSI), temporary mobile subscriber identity (TMSI), UMTS terrestrial radio access network-radio network temporary identifier (U-RNTI) exists. The terminals decoding the paging information performs following procedures corresponding to the paging information.
Also, a plurality of S-CCPCHs may be operated to obtain a paging capability according to an environment of the base station and the capacity for subscribers of the base station. When the base station is installed based on a cell specific parameter, the S-CCPCH is statically operated. The radio resource allocating method, which is statically operated in consideration of the maximum capacity, has a merit that a circuit based-system is statically operated, but has a problem that the limited radio resource is wasted.
A long term evolution (LTE) system standardized in 3GPP to provide diverse packet services is a packet based-system. An object of the LTE system is to provide a pure packet service. Therefore, in the LTE system for providing a packet service having a burst characteristic, efficient and variable methods for utilizing radio resources are needed. Accordingly, a research for simplifying and integrating diverse kinds of transport channels operated in the conventional WCDMA method are being progressed.