According to GSM/EDGE standards promulgated by the 3rd Generation Partnership Project (3GPP), a mobile station (MS) is required to periodically search for, synchronize to, and verify the identity of adjacent cells in order to ensure mobility capability. This process, which we shall refer to as BSIC decoding, includes searching for the Frequency Correction CHannel (FCCH) that indicates a given frequency is used as a Broadcast Control CHannel (BCCH) of a particular adjacent base station, decoding a Synchronization CHannel (SCH) to finely adjust to the synchronization of the adjacent cell, and then verifying that the cell is the expected one (and not another cell using the same frequency) using the Base transceiver Station Identity Code (BSIC) broadcast on the SCH.
Unfortunately, the idle frame (also termed “search” frame) allocated to perform BSIC decoding during packet transfer mode does not usually provide enough time to complete BSIC decoding when the MS is in certain multislot configurations. 3GPP TS 45.008 V7.2.0 section 10.1.1.2 states that “In some allowed multislot configurations (see 3GPP TS 45.002) the MS is not able to perform BSIC decoding or multi-RAT measurements. In this case, the MS may skip the last transmission burst in the frame immediately preceding the idle frame or skip the first reception burst in the frame immediately following the idle frame in order to comply with the requirement to search, verify and decode BSIC information, or in order to perform multi-RAT measurements.” Skipping a transmission burst in accordance with 3GPP TS 45.008 V7.2.0 section 10.1.1.2 is sometimes referred to as “extending a search window.”
Extending the search window by skipping a transmission burst, however, necessarily means that some data transmission is skipped. In certain situations, this may corrupt the transmission of the entire radio block containing the skipped burst. Thus, there is an opportunity to reduce the risk of corrupting the radio block with the skipped burst while maintaining compliance with the requirement to search, verify, and decode BSIC information. The various aspects, features and advantages of the disclosure will become more fully apparent to those having ordinary skill in the art upon careful consideration of the following Drawings and accompanying Detailed Description.
USPTO Backgrounds
USPTO Backgrounds