Patent ID: 9641371
Date: 2017-05-02
CPC Classifications: H04L

Claim:
1. A method carried out by a wireless-communication device (WCD), the method comprising: receiving a single-frequency-network-(SFN)-multicast transmission, wherein receiving the SFN-multicast transmission comprises receiving a respective SFN-multicast-transmission signal from each site in a plurality of sites in a given SFN-multicast area, each received SFN-multicast-transmission signal having a respective SFN-multicast cyclic prefix; calculating a multisource multipath delay spread (“MMDS”) that is characteristic of the received plurality of SFN-multicast-transmission signals; determining whether the calculated MMDS exceeds an MMDS threshold; selecting a multicast timing point that is (i) after the SFN-multicast cyclic prefix of a first-received one of the received SFN-multicast-transmission signals responsive to determining that the calculated MMDS exceeds the MMDS threshold or (ii) within the SFN-multicast cyclic prefix of the first-received SFN-multicast-transmission signal responsive to determining that the calculated MMDS does not exceed the MMDS threshold; using the selected multicast timing point to demodulate the received SFN-multicast transmission; obtaining a respective correlation sequence for the SFN-multicast transmission with each reference signal in a set of known reference signals, wherein the set of known reference signals includes a respective unicast reference signal from each site in the plurality of sites, wherein each obtained correlation sequence comprises a respective maximum peak, wherein locating the set of peaks comprises locating the respective maximum peak in each obtained correlation sequence; locating a set of peaks in the set of obtained correlation sequences, wherein the WCD calculates the MMDS based at least in part on the located set of peaks; and discarding at least one located maximum peak that does not exceed a correlation threshold prior to calculating the MMDS.