Method, terminal, and system for cell reselection

Abstract

A method and terminal are disclosed for cell reselection. In the disclosure, the terminal obtains a dedicated priority list and a valid time of the dedicates priority list for cell reselection from a first communication system, such as a Long Term Evolution (LTE) system, when the terminal is in a cell of the fists communication system. In case that the the terminal camps on a cell of a second communication system, such as a non-LTE system (for example, a UMTS system), and before the valid time expire, the terminal performs cell reselection using the dedicated priority list.

What is claimed is: 
     
         1 . A method for cell reselection comprising:
 receiving, by a terminal, a public priority list from a first network device of a first system;   receiving, by the terminal, from a second network device of a second system, an indication indicating that the second network device does not send a public priority list to the terminal;   storing, by the terminal, the public priority list from the first network device; and performing, by the terminal, cell reselection according to the public priority list, when the terminal is in a cell of the second system and when a dedicated priority list is invalid.   
     
     
         2 . The method according to  claim 1 , wherein the first system is a Long Term Evolution (LTE) system and the second system is a non-LTE system. 
     
     
         3 . The method according to  claim 1 , wherein the indication is carried in a broadcast information. 
     
     
         4 . The method according to  claim 1 , further comprising: deleting, by the terminal, the dedicated priority list when dedicated priority list is invalid. 
     
     
         5 . The method according to  claim 1 , wherein the dedicated priority list comprises priority information of different radio access technologies (RATs). 
     
     
         6 . The method according to  claim 5 , wherein the priority information comprises priority information of frequencies of the different RATs. 
     
     
         7 . The method according to  claim 2 , wherein the dedicated priority list comprises frequency priority information of the LTE system and the non-LTE system. 
     
     
         8 . An apparatus, comprising:
 a first circuitry, configured to receive a public priority list from a first network device of a first system, and receive from a second network device of a second system, an indication indicating that the second network device does not send a public priority list;   a second circuitry, configured to store the public priority list from the first network device; and   a third circuitry, configured to perform cell reselection according to the public priority list, when the terminal is in a cell of the second system and when a dedicated priority list is invalid.   
     
     
         9 . The apparatus according to  claim 8 , wherein the first system is a Long Term Evolution (LTE) system and the second system is a non-LTE system. 
     
     
         10 . The apparatus according to  claim 8 , wherein the indication is carried in a broadcast information. 
     
     
         11 . The apparatus according to  claim 8 , wherein the apparatus is further configured to
 delete the dedicated priority list when dedicated priority list is invalid.   
     
     
         12 . The apparatus according to  claim 8 , wherein the dedicated priority list comprises priority information of different radio access technologies (RATs). 
     
     
         13 . The apparatus according to  claim 12 , wherein the priority information comprises priority information of frequencies of the different RATs. 
     
     
         14 . A communications system, comprising:
 a first network device of a first system, configured to send a public priority list to a terminal;   a second network device of a second system, configured to send, to the terminal, an indication indicating that the second network device does not send a public priority list to the terminal;   a terminal, configured to obtain the public priority list from the first system, obtain the indication indicating that the second network device does not send a public priority list to the terminal, store the the public priority list, and perform cell reselection according to the public priority list, when the terminal is in a cell of the second system and when a dedicated priority list is invalid.   
     
     
         15 . The system according to  claim 14 , wherein the first system is a Long Term Evolution (LTE) system and the second system is a non-LTE system. 
     
     
         16 . The system according to  claim 14 , wherein the indication is carried in a broadcast information. 
     
     
         17 . The system according to  claim 14 , the terminal is further configured to delete the dedicated priority list when the dedicated priority list is invalid. 
     
     
         18 . The system according to  claim 14 , wherein the dedicated priority list comprises priority information of different radio access technologies (RATs). 
     
     
         19 . The system according to  claim 18 , wherein the priority information comprises priority information of frequencies of the different RATs. 
     
     
         20 . The system according to  claim 15 , wherein the dedicated priority list comprises frequency priority information of the LTE system and the non-LTE system.