Some mobile stakeholders have been frustrated that the first wave of 5G standards, 3GPP Release 15, have stuck with OFDM in the air interface, rather than adopting a more radical modulation technology. However, additional standards are likely to creep into Release 16 standards, which will provide renewed opportunities for new approaches from giants like Huawei, to start-ups like Cohere Technologies, with its OTFS (Orthogonal Time Frequency Space) modulation scheme. In a clear sign that OTFS is not off the table yet, US mobile operator C Spire has applied for permission to test the technology in its headquarters in Ridgeland, Mississippi, using spectrum in the 3650-3700 band. In its application, C Spire says it believes OTFS may deliver higher spectral efficiency,…