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Top1. Introduction
The fast progress in Radio Frequency Identification (RFID) communications has proved that wireless communication can be effectively used for data service for high data rates (Han, Lim, & Lee, 2007)(Björkqvist & Virtanen, 2006). Conventional wireless devices have been intended to convey a single communication service using a definite standard. It hence becomes costly to improve and maintain the wireless system each time a novel standard is launched in the market (Journal & Automotive, 2015). Hence SDR comes as a possible solution to make wireless communication systems more supple and consumer friendly. SDR refers to those reprogrammable or reconfigurable radios in which the corresponding hardware can perform various functions by the updating of the software.SDR has generated tremendous curiosity in the wireless communication business because of the wide-ranging system and deployment benefits it offers (Weis, Sarma, & Rivest, 2004)(Hannan, Islam, Samad, & Hussain, 2010).SDR increases the flexibility and extends hardware life time (Haghighat, 2002)(Marriwala, Sahu, Khullar, & Vohra, 2011). The construction of the SDR in our design primarily consists of three components i.e. a transmitter, a channel and a receiver. In this paper we have implemented and designed a Software Defined Radio (SDR) M-ary QAM Modem for Gaussian Channel using LabVIEW. SDR’s can be reconfigured and can talk and listen to multiple channels at the same time. The use of Modulation techniques in an SDR is quiet crucial since these techniques delimit the core line of all the wireless applications (Marriwala & Sahu, 2013) (States, Force, Fourier, Fourier, & Fft, 2004) (Noseworthy, n.d.) (Mitola, 1995). SDR’s flexibility must be planned well in advance by the use of software and hardware considerations, which shall result in improved code portability, superior communication life cycles, and abridged costs (Johnson, 2013). The transmitter of an SDR system converts digital signals to analog waveforms. In this paper, QAM has been chosen as the modulation scheme to be used in the SDR design as it is extensively used for different applications where transmission of data at high rate is done over band pass channels such as high speed cable, FAX modem, multi-tone wireless, and satellite channels (Bryan, 1995)(Kim, Kehtarnavaz, & Torlak, n.d.). In QAM it is possible to send two different signals simultaneously on the same carrier frequency. Digital cable television and cable modem utilize 64-QAM and 256-QAM.In this paper Gaussian noise is introduced in the channel i.e. AWGN channel is used instead of idle channel and is removed using adaptive filtering. LabVIEW is a Graphical User Interface also referred as “G” language. The main advantage of using LabVIEW in our design is that it uses data-flow-controlled execution, rather than using chronological execution of text-line based languages (Samad & Hussain, n.d.) (Vasudevan, 2010). LabVIEW has many built in function libraries for the serial, parallel and network computer ports as well as simple file operation for input-output (Cummings & Haruyama, 1999)(Hatai & Chakrabarti, 2009).