Measuring Interference and Noise Power Using Non-Content Burst Periods

Abstract

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.

What is claimed is: 
     
         1 . A method for measuring noise and interference at a Wireless terminal, comprising:
 receiving a first signal during a first period of a downlink frame, wherein the first period corresponds to a dummy period defined by a base station;   receiving a second signal during a second period of the downlink frame, wherein the second period corresponds to a burst period of the downlink frame; and   comparing the first signal to the second signal to determine a relative signal strength of noise and interference in the downlink frame.   
     
     
         2 . The method of  claim 1 , wherein the first signal is a composite of interference from other base stations and ambient noise. 
     
     
         3 . The method of  claim 2 , wherein the second signal is a composite of a desired signal, the interference from other base stations, and the ambient noise. 
     
     
         4 . The method of  claim 1 , wherein the base station is silent during the first period. 
     
     
         5 . The method of  claim 1 , wherein the first period corresponds to predetermined time and frequency slots of the downlink frame. 
     
     
         6 . The method of  claim 1 , wherein the dummy period is defined by the base station as intended to a non-existent terminal. 
     
     
         7 . The method of  claim 1 , wherein the dummy period includes a null burst from the base station. 
     
     
         8 . The method of  claim 1 , wherein the downlink frame comprises a plurality of orthogonal frequency domain modulation (OFDM) symbols. 
     
     
         9 . A communication system, comprising:
 a receiver configured to receive a first signal during a first period of a frame and a second signal during a second period of the frame, wherein the first period corresponds to a dummy period of the frame and the second period corresponds to a burst period of the frame; and   a noise and interference measurement module configured to compare the first signal to the second signal to determine a relative signal strength of noise and interference in the frame.   
     
     
         10 . The communication system of  claim 9 , wherein the frame corresponds to a downlink frame transmitted from a base station to the communication system, and wherein the base station is silent during the first period. 
     
     
         11 . The communication system of  claim 10 , wherein the first signal is a composite of interference from other base stations and ambient noise. 
     
     
         12 . The communication system of  claim 11 , wherein the second signal is a composite of a desired signal from the base station, the interference from other base stations, and the ambient noise. 
     
     
         13 . The communication system of  claim 10 , wherein the dummy period is defined by the base station as intended to a non-existent terminal or includes a null burst from the base station. 
     
     
         14 . The communication system of  claim 9 , wherein the frame corresponds to an uplink frame transmitted by one or more terminals assigned to the communication system, and wherein the one or more terminals are silent during the first period. 
     
     
         15 . The communication system of  claim 14 , wherein the first signal is a composite of interference from terminals not assigned to the communication system and ambient noise. 
     
     
         16 . The communication system of  claim 15 , wherein the second signal is a composite of a desired signal from the one or more terminals assigned to the communication system, the interference from the terminals not assigned to the communication system, and the ambient noise. 
     
     
         17 . A method for measuring noise and interference at a base station, comprising:
 receiving a first signal during a first period of an uplink frame, wherein the first period corresponds to a dummy period defined by the base station;   receiving a second signal during a second period of the uplink frame, wherein the second period corresponds to a burst period of the uplink frame; and   comparing the first signal to the second signal to determine a relative signal strength of noise and interference in the uplink frame.   
     
     
         18 . The method of  claim 17 . Wherein the uplink frame includes bursts transmitted from one or more terminals assigned to the base station, and wherein the one or more terminals are silent during the first period. 
     
     
         19 . The method of  claim 18 , wherein the first signal is a composite of interference from terminals not assigned to the base station and ambient noise. 
     
     
         20 . The method of  claim 19 , wherein the second signal is a composite of a desired signal from the one or more terminals assigned to the base station, the interference from the terminals not assigned to the base station, and the ambient noise.