Selecting modulation and coding scheme in the presence of interference
View Patent ↗A wireless device comprises an interference sensing module, a modulation and coding schemes (MCS) selection module, and a transmit module. The interference sensing module selectively receives an interference signal over a channel. The interference signal is modulated using P MCSs, where P is an integer greater than or equal to 1. The MCS selection module selects an MCS based on the P MCSs. The transmit module transmits a transmit signal over the channel using the MCS.
1. A system configured to be implemented in a first wireless device, the system comprising:
a sensing module configured to
sense whether an interference signal is present in a wireless channel,
determine, in response to an interference signal being present in the wireless channel, whether the interference signal is an un-modulated noise signal or a modulated signal transmitted over the wireless channel by a second wireless device, wherein the second wireless device is separate from the first wireless device, and
determine, in response to the interference signal being a modulated signal transmitted by a second wireless device, a modulation and coding scheme used by the second wireless device to transmit the modulated signal over the wireless channel;
a channel capacity module configured to determine modulation constrained capacities of the wireless channel for a plurality of modulation and coding schemes, wherein a modulation constrained capacity of the wireless channel for a given modulation and coding scheme is a maximum number of bits that can be reliably transmitted over the wireless channel using the given modulation and coding scheme, and wherein the plurality of modulation and coding schemes includes
in response to i) the interference signal being a modulated signal transmitted by a second wireless device and ii) the sensing module being able to determine the modulation and coding scheme of the modulated signal, the modulation and coding scheme of the modulated signal, or
in response to i) the interference signal being a modulated signal transmitted by a second wireless device and ii) the sensing module not being able to determine the modulation and coding scheme of the modulated signal, one or more modulation and coding schemes that can be used by the second wireless device to transmit the modulated signal over the wireless channel; and
a selection module configured to select, based on the modulation constrained capacities, one of the plurality of modulation and coding schemes to transmit a signal from the first wireless device over the wireless channel.
2. The system of claim 1 , further comprising a transmit module configured to transmit the signal over the wireless channel using the selected one of the plurality of modulation and coding schemes.
3. The system of claim 1 , wherein the selection module is configured to select a modulation and coding scheme having a smallest one of the channel capacities as the selected one of the plurality of modulation and coding schemes.
4. The system of claim 1 , wherein the selection module is configured to select a modulation and coding scheme having a channel capacity greater than or equal to a predetermined threshold as the selected one of the plurality of modulation and coding schemes.
5. The system of claim 1 , wherein the selection module is configured to:
determine whether one or more of the plurality of modulation and coding schemes have channel capacities greater than or equal to a predetermined threshold, and
select, from the one or more of the plurality of modulation and coding schemes, a modulation and coding scheme having a highest data rate as the selected one of the modulation and coding schemes.
6. The system of claim 1 , further comprising:
an averaging module configured to generate average channel capacities by averaging the channel capacities over a plurality of time slots or a plurality of frequency slots,
wherein the selection module is configured to select a modulation and coding scheme having an average channel capacity greater than or equal to a predetermined threshold as the selected one of the plurality of modulation and coding schemes.
7. The system of claim 1 , further comprising:
an averaging module configured to generate average channel capacities by averaging the channel capacities over a plurality of time slots or a plurality of frequency slots,
wherein the selection module is configured to
determine whether one or more of the plurality of modulation and coding schemes have average channel capacities greater than or equal to a predetermined threshold, and
select, from the one or more of the plurality of modulation and coding schemes, a modulation and coding scheme having a highest data rate as the selected one of the modulation and coding schemes.
8. A first wireless device, comprising:
the system of claim 1 , wherein the first wireless device is associated with a first base station, and wherein the second wireless device is a second base station separate from the first base station; and
a transmit module configured to transmit the selected one of the plurality of modulation and coding schemes to the first base station,
wherein, in response to transmitting the selected one of the plurality of modulation and coding schemes to the first base station, the first wireless device is configured to receive data transmitted from the first base station in accordance with the selected one of the plurality of modulation and coding schemes.
9. A method to be implemented in a first wireless device, the method comprising:
sensing whether an interference signal is present in a wireless channel;
determining, in response to an interference signal being present in the wireless channel, whether the interference signal is an un-modulated noise signal or a modulated signal transmitted over the wireless channel by a second wireless device, wherein the second wireless device is separate from the first wireless device;
determining, in response to the interference signal being a modulated signal transmitted by a second wireless device, a modulation and coding scheme used by the second wireless device to transmit the modulated signal over the wireless channel;
determining modulation constrained capacities of the wireless channel for a plurality of modulation and coding schemes, wherein
a modulation constrained capacity of the wireless channel for a given modulation and coding scheme is a maximum number of bits that can be reliably transmitted over the wireless channel using the given modulation and coding scheme, and
the plurality of modulation and coding schemes includes
in response to i) the interference signal being a modulated signal transmitted by a second wireless device and ii) the sensing module being able to determine the modulation and coding scheme of the modulated signal, the modulation and coding scheme of the modulated signal, or
in response to i) the interference signal being a modulated signal transmitted by a second wireless device and ii) the sensing module not being able to determine the modulation and coding scheme of the modulated signal, one or more modulation and coding schemes that can be used by the second wireless device to transmit the modulated signal over the wireless channel; and
selecting, based on the modulation constrained capacities, one of the plurality of modulation and coding schemes to transmit a signal from the first wireless device over the wireless channel.
10. The method of claim 9 , further comprising transmitting the signal over the wireless channel using the selected one of the plurality of modulation and coding schemes.
11. The method of claim 9 , further comprising selecting a modulation and coding scheme having a smallest one of the channel capacities as the selected one of the plurality of modulation and coding schemes.
12. The method of claim 9 , further comprising selecting a modulation and coding scheme having a channel capacity greater than or equal to a predetermined threshold as the selected one of the plurality of modulation and coding schemes.
13. The method of claim 9 , further comprising:
determining whether one or more of the plurality of modulation and coding schemes have channel capacities greater than or equal to a predetermined threshold; and
selecting, from the one or more of the plurality of modulation and coding schemes, a modulation and coding scheme having a highest data rate as the selected one of the modulation and coding schemes.
14. The method of claim 9 , further comprising:
generating average channel capacities by averaging the channel capacities over a plurality of time slots or a plurality of frequency slots; and
selecting a modulation and coding scheme having an average channel capacity greater than or equal to a predetermined threshold as the selected one of the plurality of modulation and coding schemes.
15. The method of claim 9 , further comprising:
generating average channel capacities by averaging the channel capacities over a plurality of time slots or a plurality of frequency slots;
determining whether one or more of the plurality of modulation and coding schemes have average channel capacities greater than or equal to a predetermined threshold; and
selecting, from the one or more of the plurality of modulation and coding schemes, a modulation and coding scheme having a highest data rate as the selected one of the modulation and coding schemes.