Measuring noise power at wireless receivers using pilot symbol information
View Patent ↗Embodiments are directed to a wireless receiver system that utilizes a special structure of pilot symbols used for synchronization and channel estimation in transmission packets to measure noise power at the receiver. The periodicity of the pilot signal sequences is used to extract the noise power from the received signal. Such extraction is achieved by subtracting the received signals from two pilot slots which are separated by the known periodicity of the training sequence. This method relies on the fact that desired signal and system interference signals will cancel out after the subtraction process. Measuring the power of the residual signal after subtraction represents the estimate of the noise power. Several consecutive such residual signals can be first summed up before measuring the power to improve the estimate of the noise power at the receiver. To further improve the performance, estimates of the desired signal produced by a channel estimation block can be first subtracted from each of the received signals on two pilot slots which are then to be subtracted and are separated by the known periodicity of the pilot sequence.
1. A method of measuring noise power in a receiver of a communication system comprising:
receiving a received signal that is organized into a plurality of data frames;
utilizing a known periodicity of the received signal as defined by the communication system, in order to determine the average noise power for a number of frames in a transmission by subtracting the received signal from two reference slots that are separated by the known periodicity.
2. The method of claim 1 wherein the known periodicity is defined by the regular recurrence of pilot signals transmitted during each frame of the plurality of data frames.
3. The method of claim 1 wherein the communication system comprises a wireless communication system.
4. The method of claim 3 wherein the wireless communication system comprises one of the group consisting of IEEE 802.11, IEEE 801.16, and Wimax protocols.
5. The method of claim 4 wherein each frame comprises a plurality of orthogonal frequency domain modulation (OFDM) symbols.
6. The method of claim 2 wherein the pilot signals are transmitted during the preamble of each frame.
7. The method of claim 6 wherein the frame comprises zone and data bins, and wherein the pilot signals are transmitted during a zone of each frame.
8. A communications system comprising:
a receiver section receiving desired transmissions from a transmitter over a wireless connection; and
a noise power determination component utilizing a known periodicity of the received desired transmissions as defined by the communication system, in order to determine the average noise power for a plurality of data frames in a transmission by subtracting the received signal from two reference slots that are separated by the periodicity.
9. The communications system of claim 8 wherein the known periodicity is defined by the regular recurrence of pilot signals transmitted during each frame of the plurality of data frames.
10. The communications system of claim 8 wherein the communication system comprises a wireless communication system, and wherein the wireless communication system comprises one of the group consisting of IEEE 802.11, IEEE 801.16, and Wimax protocols.
11. The communications system of claim 10 wherein each frame comprises a plurality of orthogonal frequency domain modulation (OFDM) symbols.
12. The communications system of claim 9 wherein the pilot signals are transmitted during the preamble of each frame.
13. The communications system of claim 12 wherein the frame comprises zone and data bins, and wherein the pilot signals are transmitted during a zone of each frame.