The Study of OFDM ICI Cancellation Schemes in 2.4 GHz Frequency Band Using Software Defined Radio

In Orthogonal Frequency Division Multiplexing (OFDM), frequency offset is a common problem that causes inter-carrier-interference (ICI) that degrades the quality of the transmitted signal. Many theoretical studies of the different ICI-cancellation schemes have been reported earlier by many authors. The need for experimental verification of the theoretically predicted results in 2.4 GHz frequency band is important. One of most widely used systems is Wi-Fi (IEE 802.11b) that makes use of this frequency band for short range wireless communication with throughput as high as 11 Mbps. In this work, several new ICI cancellation schemes have been tested in 2.4 GHz frequency using open source Software Defined Radio (SDR) namely GNU Radio. The GNU Radio system used in the experiment had two Universal Software Radio Peripheral (USRP N210) modules connected to a computer. Both the USRP units had one-daughterboard (XCVR2450) each for transmission and reception of radio signals. The input data to the USRP was prepared in compliance with IEEE-802.11b specification. The experimental results were compared with the theoretical results of the new Inter-Carrier Interference (ICI) cancellation schemes. The comparison of the results revealed that the new schemes are suitable for high performance transmission. The results of this paper open up new opportunities of using OFDM in heavily congested 2.4 GHz and 5 GHz bands (WiFi5: IEEE 802.a) for error free data transmission. The schemes also can be used in other frequencies where channels are heavily congested.