Method and system for orthogonal multi-protocol transmissions
Methods and systems for multi-protocol transmissions in shared spectrum are disclosed where an OFDM transmitter is configured to generate transmissions associated with one OFDM technology or protocol using subcarriers of another OFDM technology. Generally, an OFDM transmitter may be configured to map or assign the different OFDM signals to different subsets of the available OFDM subcarriers such that the data contained therein can be transmitted at the same or during an overlapping time interval. In one application, an LTE transmitter is configured to generate and/or transmit LTE information using LTE subcarriers located in unused portion(s) of the Wi-Fi system bandwidth independently of or in addition to transmitting Wi-Fi or LTE information using LTE subcarriers located in portions of the Wi-Fi system bandwidth normally occupied by Wi-Fi subcarriers.
1. A method for an Orthogonal Frequency Division Multiplexing, OFDM, transmitter configured for OFDM signal transmissions, the method comprising:
generating a first OFDM signal containing data associated with a first OFDM communication protocol, the first OFDM communication protocol defined to use a first system bandwidth that overlaps with a second system bandwidth associated with a second OFDM communication protocol;
transmitting the first OFDM signal over a non-utilized portion of the second system bandwidth; and
generating a second OFDM signal containing data associated with the second OFDM communication protocol, and transmitting the second OFDM signal over the second system bandwidth,
wherein transmitting the first OFDM signal comprises transmitting the first OFDM signal over the non-utilized portion of the second system bandwidth if another transmission is in progress in the second system bandwidth.
2. The method of claim 1 wherein the first OFDM signal is transmitted using a first subset of a first plurality of subcarriers having a first subcarrier frequency spacing, the first subset being located in the non-utilized portion of the second system bandwidth.
3. The method of claim 1 wherein the first and second OFDM signals are transmitted at a same or a different time.
4. The method of claim 1 wherein if no other transmission is in progress in the second system bandwidth, the method further comprising, prior to transmitting the first OFDM signal, transmitting the second OFDM signal over the second system bandwidth, wherein the second OFDM signal is indicative of one of a transmission length, transmission time, transmission type and a channel reservation time associated with at least one of the first and second OFDM signals, and wherein the first OFDM signal is subsequently transmitted over the second system bandwidth.
5. The method of claim 1 wherein the second OFDM signal is transmitted using a second plurality of subcarriers having a second subcarrier frequency spacing different than the first subcarrier frequency spacing, the second plurality of subcarriers being located in a utilized portion of the second system bandwidth.
6. The method of claim 1 wherein the first and second OFDM signals are generated in one of a time domain and a frequency domain, based on respective first and second predetermined OFDM signals containing data associated with the first and second OFDM communication protocols.
7. The method of claim 6 wherein generating the second OFDM signal further comprises generating the second predetermined OFDM signal, and interpolating the second predetermined OFDM signal generated using the first plurality of subcarriers to produce an interpolated OFDM signal that can be mapped to subcarriers in the second subset.
8. The method of claim 1 wherein the first OFDM signal comprises an LTE signal and the second OFDM signal comprises one of a Clear To Send (CTS) frame, a Short Training Field (STF), a Long Training Field (LTF), and a Signal Field (SIG).
9. An Orthogonal Frequency Division Multiplexing, OFDM, transmitter configured for OFDM signal transmissions, the OFDM transmitter having circuitry containing instructions which, when executed, are configured to cause the OFDM transmitter to:
generate a first OFDM signal containing data associated with a first OFDM communication protocol, the first OFDM communication protocol defined to use a first system bandwidth that overlaps with a second system bandwidth associated with a second OFDM communication protocol, and
transmit the first OFDM signal over a non-utilized portion of the second system bandwidth,
wherein the instructions which, when executed, are further configured to cause the OFDM transmitter to generate a second OFDM signal containing data associated with the second OFDM communication protocol, and to transmit the second OFDM signal over the second system bandwidth,
wherein to transmit the first OFDM signal, the instructions are further configured to cause the OFDM transmitter to transmit the first OFDM signal over the non-utilized portion of the second system bandwidth if another transmission is in progress in the second system.
10. The OFDM transmitter of claim 9 wherein the first OFDM signal is transmitted using a first subset of a first plurality of subcarriers having a first subcarrier frequency spacing, the first subset being located in the non-utilized portion of the second system bandwidth.
11. The OFDM transmitter of claim 9 wherein the first and second OFDM signals are transmitted at a same or a different time.
12. The OFDM transmitter of claim 9 wherein if no other transmission is in progress in the second system bandwidth, the instructions are further configured to cause the OFDM transmitter to transmit the second OFDM signal over the second system bandwidth prior to transmitting the first OFDM signal, wherein the second OFDM signal is indicative of one of a transmission length, transmission time, transmission type and a channel reservation time associated with at least one of the first and second OFDM signals, and wherein the first OFDM signal is subsequently transmitted over the second system bandwidth.
13. The OFDM transmitter of claim 9 wherein the second OFDM signal is transmitted using a second plurality of subcarriers having a second subcarrier frequency spacing different than the first subcarrier frequency spacing, the second plurality of subcarriers being located in a utilized portion of the second system bandwidth.
14. The OFDM transmitter of claim 9 wherein the first and second OFDM signals are generated in one of a time domain and a frequency domain, based on respective first and second predetermined OFDM signals containing data associated with the first and second OFDM communication protocols.
15. The OFDM transmitter of claim 14 wherein to generate the second OFDM signal, the instructions are further configured to cause the OFDM transmitter to generate the second predetermined OFDM signal, and interpolate the second predetermined OFDM signal generated using the first plurality of subcarriers to produce an interpolated OFDM signal that can be mapped to subcarriers in the second subset.
16. The OFDM transmitter of claim 9 wherein the first OFDM signal comprises an LTE signal and the second OFDM signal comprises one of a CTS frame, a STF, a LTF, and a SIG.