Cell searching system and method
For wireless networks that transmit synchronization signals allowing user equipment to synchronize to cells within the network and transmit reference signals allowing user equipment to determine cell identities, a method and apparatus taught herein advantageously link the synchronization signal sequences to the reference signal sequences according to a defined mapping. The linking simplifies the cell search process by allowing user equipment to determine cell identities based on mapping detected synchronization signal sequences to the corresponding reference signal or to the corresponding subset of reference signals in embodiments where there are more reference signal sequences than synchronization signal sequences. In at least one embodiment, the network is a 3G LTE network and at least the Primary Synchronization Signal (P-SyS) sequences are linked to the Downlink (DL) reference symbol sequences according to a defined mapping, thereby allowing to user equipment to determine cell identities from detected P-SyS sequences.
1. A method in a wireless communication network of facilitating cell search processes by user equipment needing to synchronize with cells in said wireless communication network, the method comprising:
defining a set of synchronization signal sequences to be used for generating individual synchronization signals;
defining a set of reference signal sequences to be used for generating individual reference signals;
linking the synchronization signal sequences to the reference signal sequences according to a defined mapping to thereby enable user equipment to determine cell identities based on mapping detected synchronization signal sequences to corresponding reference signal sequences according to the defined mapping, wherein linking the synchronization signal sequences to the reference signal sequences according to the defined mapping comprises maintaining a direct mapping between individual synchronization signal sequences and individual reference signal sequences, or between unique combinations of primary and secondary synchronization signal sequences and individual reference signal sequences, so that user equipment can identify the particular reference signal sequence in use in a given cell based on the defined mapping and without need for actually detecting the reference signal sequence being conveyed by the reference signal transmitted for the cell;
generating individual ones of the synchronization and reference signals at each of one or more base stations in the wireless communication network, in accordance with said defined mapping, and
transmitting the generated synchronization and reference signals from respective ones of the one or more base stations, to allow user equipment to synchronize with cells associated with the one or more base stations, and to determine cell identities for those cells based on mapping synchronization signal sequences to reference signal sequences according to said defined mapping.