Multi-ofdm-protocol beacon operation

Abstract

Methods and systems for multi-protocol beacon operation in shared spectrum (unlicensed band) are disclosed where an OFDM transmitter is configured to generate transmissions associated with one OFDM technology or protocol using subcarriers of another OFDM technology. In one application, an LTE transmitter (LTE-U) uses LTE subcarriers to generate an interpolated 802.11 (e.g. Wi-Fi) beacon transmission that can be understood by Wi-Fi receivers, for example to reserve the channel for a subsequent LTE transmission. For instance a W-LAN preamble is generated where STF and LTF fields consist in respectively 12 and 52 subcarriers mapped at their respective frequency locations among the 2048 LTE subcarriers with the remaining subcarriers set to 0. In some implementations, the use of beacons can be useful in implementations where it is desirable to gain prioritized access to reserve the channel. Examples of suitable LTE transmissions that would benefit from prioritized channel access include delay or time-sensitive LTE transmissions or transmissions that must occur within a certain time window and/or with a certain periodicity such as LTE control data or signals (e.g. PDCCH), and/or synchronization or reference signals such as the Discovery Reference Signal (DRS) for LAA-LTE). An LTE transmitter can exploit the 802.11 channel access to gain prioritized channel access for transmitting 802.11 Wi-Fi beacons generated using its LTE subcarriers to ensure LTE transmissions take priority over other types of LTE and/or Wi-Fi traffic.