Field Theory Analysis for Wireless Infrared System’s Error Correction Munsif Ali Jatoi 1 , Nidal Kamel 1 , Firas Ousta 1 , Syed Jamal Safdar Gardezi 1 1 Center for Intelligent Signals and Imaging Research, Department of Electrical and Electronic Engineering, Universiti Teknologi PETRONAS, Perak, Malaysia. munsif.jatoi@gmail.com Abstract—Wireless infrared communications (WIR) is explained as the light waves propagation in free space by means of infrared radiation which exists in 400-700nm.This range corresponds to high frequency range which is useful for higher data rate applications. Therefore, wireless infrared is applied for higher data rates applications such as wireless computing, wireless video and wireless multimedia communication applications. Introduced by Gfeller, this field has grown with various link configurations, improved transmitter efficiency, improved receiver responsivity and various multiple access techniques for improved quality. Then major contribution of noise in these systems is background light, which reduces system performance. The system error can be reduced by introduction of some error removal techniques. This paper provides a brief account on field theory used for error correction in wireless infrared systems. The results are produced in terms of bit error rate (BER) and signal to noise ratio (SNR) for various bit length to show the ability of encoding and decoding algorithms. Keywords— Wireless Infrared system, Group Theory, Signal to noise ratio (SNR), Bit Error rate (BER). I. INTRODUCTION The need to provide higher data rates in various wireless computational and multimedia applications has increased the interest in development of wireless infrared as an efficient wireless media [1-6].Wireless infrared communications (WIR) is a term used to explain a communication technique where infrared radiation is used in the range of 400-700nm. The frequency range matches to this wavelength is in Terahertz (THz) which is adequate choice for applications demanding higher data rates. The idea was first introduced in [7]. After this, there starts an era for development in this area with various link configurations, better transmitter/receiver efficiency and multiple access techniques to achieve better performance [8]. The transmitter used for Wireless infrared systems is either a light emitting diode (LED) or a Laser diode (LD). For the conversion of the optical signal back to an electrical signal for further processing, a receiver is used. The practical options available for that include an Avalanche photodiode (APD) and a p-i-n diode. The arrangement of receiver and transmitter is referred to as the Link type. The one is called Line-of-sight (LOS) and other one is Non LOS. In the LOS configuration, there is clear path between transmitter and receiver which means that both are pointed at each other for communication. The other type achieves the communication by reflecting or bouncing the signals from walls and ceilings within indoor infrared communication. The modulation technique which is commonly employed for wireless infrared communications is intensity modulation/direct detection (IM/DD).This can be defined as the process of varying the bias current of a laser diode or LED, and then detection is carried out by receiver (such as a p-i-n photodiode) which produces the current. In other words, the optical power which the transmitter emits is collected by the surface of detector in system. Now the amount of photocurrent produced by the detector depends upon responsivity (r), the surface area of the photo detector and noise in environment [10]. Errors are caused due to background lights, which ultimately degrade system efficiency in terms of lower SNR and high cost to impart error control mechanism. Therefore for Wireless infrared systems, error correction techniques are used to remove the errors at the transmission and reception end. This paper discusses basics of field theory applied for forward error correction (FEC) for wireless infrared communication systems. Section II discusses Forward error correction; Section III is dedicated for field theory as applied for FEC in WIR systems. Section IV presents the results and discussion. Section V produces the conclusion. II. FORWARD ERROR CORRECTION FEC is commonly applied in communication systems to minimize the errors by addition of redundant bits at the transmitter end in order that the receiver is able to get error free information [7]. In the simplified model of communication module, the transmitter transmits a k bit long data sequence to encoder. The encoder here adds parity bits into actual data which makes the data sequence of length n. The encoded data is then received by decoder which decodes back the original data without errors. The designation used for codes is (n, k) where n is the output code bits and k is input data bits. The basic measure of the system performance is 978-1-4799-4653-2/14/$31.00 © 2014 IEEE