Measuring interference and noise power using non-content burst periods
Embodiments describe a method of measuring noise and interference within transceivers of an OFDM wireless transmission system, or similar communication system, including a number of receivers communicating with one or more base stations in cell or sector arrangements. The transmitter schedules a transmission burst for a non-existent user (receiver) using wireless transmission traffic. In an OFDM system, this corresponds to a certain set of subcarriers in the time/frequency arrangement. Thus, in the receive frame structure, the data and pilot subcarriers are guaranteed to be only noise and interference from adjacent sectors. The receiver can accurately measure the noise and interference without needing to cancel out the transmitted signal. Therefore, the system is assured that there is no desired signal as part of this measurement. The noise and interference measurement process can be appropriately scheduled so that it does not impact the overall throughput of the system. This mechanism creates a deterministic place (in time and/or frequency) within the transmission, where no desired signal is required.
1. A method of measuring noise and interference signal levels in a communication system comprising:
receiving a first signal during a first period, wherein the first period is within a frame of data transmission defined by a protocol utilized by the communication system, wherein desired data is restricted from being transmitted during the first period, and wherein the first signal is a composite of noise and interference;
receiving a second signal during a second period of the frame, wherein desired data is transmitted between a transmitter and a receiver within at least the second period of the frame, and wherein the second signal is a composite of a desired signal and said noise and interference; and
comparing a signal level of the first signal to a signal level of the second signal to determine a relative signal strength of said noise and interference during the frame.
2. The method of claim 1 , wherein the noise and interference comprise ambient noise and interference from at least one source other than the transmitter.
3. The method of claim 2 , wherein the protocol defines one or more bursts in the frame, transmitted between the transmitter and one or more target receivers including the receiver, each burst intended to be received by a single receiver of the target receivers.
4. The method of claim 3 , wherein the transmitter comprises a basestation, and the one or more bursts are transmitted from the basestation to the receiver in a downlink transmission.
5. The method of claim 3 , wherein the receiver comprises a receiving terminal and the transmitter comprises a basestation.
6. The method of claim 1 , wherein the communication system operates according to a wireless communication protocol.
7. The method of claim 6 , wherein the wireless communication protocol comprises one of the group consisting of: IEEE 802.11, IEEE 801.16, WiMAX, and Zigbee protocols.
8. The method of claim 7 , wherein the frame comprises a plurality of orthogonal frequency domain modulation (OFDM) symbols.
9. The method of claim 8 , wherein the first period comprises a dummy burst reserved by the transmitter for measurement of noise and interference levels by the receiver during a downlink transmission.
10. An apparatus comprising:
a receiver configured to receive a first signal during a first period of a frame, wherein desired data is restricted from being transmitted during the first period, and wherein the first signal is a composite of noise and interference, and to receive a second signal during a second period of the frame, wherein desired data is received from a transmitter during at least the second period of the frame, and wherein the second signal is a composite of a desired signal and said noise and interference;
a processor configured to measure a first signal level of the first signal and a second signal level of the second signal, and to compare the first signal level to the second signal level to determine a relative signal strength of said noise and interference during the frame.
11. The apparatus of claim 10 , wherein the apparatus operates according to a wireless communication protocol, and wherein the wireless communication protocol comprises one of the group consisting of: IEEE 802.11, TEEE 801.16, Wimax, and Zigbee protocols.
12. The apparatus of claim 11 , wherein the frame comprises a plurality of orthogonal frequency domain modulation (OFDM) symbols.
13. The apparatus of claim 12 , wherein the first period comprises a dummy burst reserved by a basestation for measurement of noise and interference levels by the processor during a downlink transmission.
14. The apparatus of claim 10 , wherein the noise and interference comprise ambient noise and interference from at least one source other than the transmitter.
15. The apparatus of claim 14 , wherein the apparatus operates according to a wireless communication protocol, and wherein the wireless communication protocol defines one or more bursts in the frame, transmitted between the transmitter and one or more target receivers including the receiver, each burst intended to be received by a single receiver of the target receivers.
16. The apparatus of claim 15 , wherein the transmitter comprises a basestation, and the one or more bursts are transmitted from the basestation to the receiver in a downlink transmission.
17. The apparatus of claim 15 , wherein the receiver comprises a receiving terminal and the transmitter comprises a basestation.