Multi-network overlaid cell detection
View Patent ↗A communications system includes a wireless telephony network and a wireless Local Area Network (LAN), both accessible by a mobile communications device ( 16 ). To facilitate transitioning of the mobile communications device to the wireless LAN from the wireless telephony network, the wireless LAN includes a beacon transmitter, which generates a synchronization channel having a pattern unique to the wireless LAN. The Wireless LAN synchronization channel is received at a first receiver in the mobile communications device together with a synchronization channel from the wireless telephony. The wireless LAN synchronization channel enables the mobile communication device to synchronize with, for transitioning to, the wireless LAN.
1. A method for enabling a mobile communications device to transition from a first wireless communications network to a second wireless communications network, comprising the steps of:
generating in the second network a second network synchronization signal having a prescribed pattern unique to the second network; and
broadcasting the second network synchronization signal for receipt at a common receiver in the mobile communications device together with a first network synchronization signal from the first network to enable to the mobile communications device to synchronize with, and transition to, the second wireless communications network;
wherein the second network synchronization signal is transmitted at a same frequency as the first network synchronization signal; and
wherein the generating step comprises generating a Secondary-Synchronization Signal of a type utilized within the first wireless communications network for achieving frame synchronization and scrambling code detection in connection with a cell search.
2. The method according to claim 1 wherein the generating step comprises the step of generating a Primary-Synchronization Signal of a type utilized within the first wireless communications network for cell searching.
3. A method of operating a mobile communications device to enable a seamless transition from a first wireless communications network to a second wireless communications network, comprising the steps of:
receiving at a common receiver in the mobile communications device a second network synchronization signal from the second wireless communications network together with a first network synchronization signal from the first wireless communications network; the second network synchronization signal having a pattern unique to the second wireless communications network, and having a same frequency as the first network synchronization channel;
establishing the identity of the second wireless communications network by matching the pattern of second network synchronization signal with the pattern associated with the second wireless communications network; and
transitioning to the second communications network after the identity thereof has been established;
wherein the second network synchronization signal comprises a Secondary-Synchronization signal of a type utilized within the first wireless communications network for achieving frame synchronization and scrambling code detection in connection with a cell search.
4. The method according to claim 3 wherein the establishing step is performed while the mobile communications device operates in a Frequency Division Duplex mode.
5. The method according to claim 3 wherein the establishing step is performed while the mobile communications device operates in a Time Division Duplex Mode.
6. The method according to claim 3 wherein the second network synchronization signal comprises a Primary-Channel Synchronization signal of a type utilized within the first wireless communications network for cell searching.