Abstract: Disclosed is a system for mitigating co-channel interference (CCI) caused due to narrow multiband signal in white space (WS) modems. The system includes a base-station that includes a base-station transmitter and a base-station receiver. The base-station receiver receives an orthogonal frequency division multiplexing signal (OFDM) from one or more customer premises equipment (CPE) transmitters. An interference detection module detects a presence of co-channel interference in carriers of the OFDM signal and determines co-channel interference affected carriers. A dynamic notch filter module receives the central interference carriers from interference detection module and mitigates the co-channel interference of co-channel interference affected carriers without affecting frame detection capability of the system.

Abstract: Disclosed is a system for mitigating co-channel interference (CCI) in white space (WS) modems. The system includes a base-station that includes a base-station transmitter and a base-station receiver. The base-station receiver receives an OFDM signal from one or more CPE transmitters. An interference detection module detects presence of co-channel interference in carriers of the OFDM signal and determines co-channel interference affected carriers. A dynamic notch filter module (i) receives central interference carriers from interference detection module and (ii) mitigates the co-channel interference of co-channel interference affected carriers without affecting frame detection capability of the system. An interference aware signal to noise ratio (SNR) estimation module determines an average signal to noise ratio (SNR) of (i) interference unaffected carriers and (ii) co-channel interference affected carriers.

Abstract: A method of ranging and sub-carrier selection in an orthogonal frequency division multiple access (OFDMA) system and the OFDMA system is disclosed. An OFDM symbol is received from a customer premises equipment (CPE) at a base station. The OFDM symbol is demodulated for obtaining a plurality of subcarriers. A plurality of data subcarriers are multiplied by zeros and stored. A plurality of uniformly spaced subcarriers is extracted from the stored subcarriers. A ranging CPE is detected in uniformly spaced subcarriers. Delay estimation is performed using the stored plurality of subcarriers upon detecting presence of ranging CPE. A method of subcarrier allocation at a ranging CPE transmitter based on total number of subcarriers, subcarriers in used band, a delay spread to be supported in terms of number of samples, a required ratio of highest amplitude to second highest amplitude of the ranging signal is disclosed.