Initial cell search in wireless communication systems
AssigneeInterDigital Technology Corporation
InventorsAlpaslan Demir, Donald M. Grieco, John W. Haim, Andrew F. Bednarz, Philip J. Pietraski, Louis J. Guccione, Prabhakar R. Chitrapu
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Abstract
A method and system for performing initial cell search is disclosed. Step 1 processing is preformed to detect a peak primary synchronization code (PSC) location (i.e. chip offset or chip location). Step 2 processing is performed to obtain the toffset and code group. Step 3 processing is performed to identify the midamble of a base station with which the WTRU performing the initial cell search may synchronize with.
Claims6
A method for wireless communication initiation implemented in a wireless transmit/receive unit (WTRU) configured to communicate with base stations of a wireless system where the WTRU receives an identifying synchronization channel (SCH) signal from at least one base station at a predetermined chip rate in a selected portion of a system time frame, comprising:
- receiving a wireless signal including at least one SCH signal, wherein the SCH signal has been transmitted in a predetermined timeslot of a system time frame and includes a primary synchronization code (PSC) transmitted in the timeslot at a predetermined chip offset wherein the decoding includes determining a toffset at which the selected SCH is transmitted;
- identifying received SCH signals using a power threshold based on a plurality of chip samples sampled at twice the chip rate;
- selecting an identified SCH signal for decoding;
- decoding the selected SCH signal to determine system time frame timing and base station identity by determining a beginning of the SCH signal by identifying a chip location having a highest signal to noise ratio wherein the noise is computed using a predetermined number of chips that is less than the total number of chips in a frame;
- and
- identifying whether the chip location of the PSC sequence was derived from an even sample or an odd sample where the PSC sequence is identified by processing a wireless communication signal at twice the chip rate.
A wireless transmit/receive unit (WTRU) configured to communicate with base stations of a wireless system where the WTRU has received an identifying synchronization channel (SCH) from at least one base station in a selected portion of a system time frame, comprising:
- a receiver configured to receive a wireless signal including at least one SCH signal, wherein the SCH signal has been transmitted in a predetermined timeslot of a system time frame and includes a primary synchronization code (PSC) transmitted in the timeslot at a predetermined chip offset wherein the decoding includes determining a toffset at which the selected SCH is transmitted;
- at least one correlator configured to identify received SCH signals using a power threshold based on a plurality of chip samples sampled at twice the chip rate;
- a processor configured to select an identified SCH signal for de coding;
- a processor configured to decode the selected SCH signal to determine system time frame timing and base station identity by determining a beginning of the SCH signal by identifying a chip location having a highest signal to noise ratio wherein the noise is computed using a predetermined number of chips that is less than the total number of chips in a frame;
- and
- circuitry configured to identify whether the chip location of the PSC sequence was derived from an even sample or an odd sample where the PSC sequence is identified by processing a wireless communication signal at twice the chip rate.
Dependencies are inferred from the claim text.