Analysis of infrared wireless links employing multibeam transmitters and imaging diversity receivers

We analyze the improvements obtained in wireless infrared (IR) communicatio n links when one replaces traditional single-element receivers by imaging r eceivers and diffuse transmitters by multibeam (quasi-diffuse) transmitters . This paper addresses both line-of-sight (LOS) and nonline-of-sight (non-L OS) IR links. We quantify link performance in terms of the transmitter powe r required to achieve a bit error rate (BER) not exceeding 10(-9) with 95% probability. Our results indicate that in LOS links, imaging receivers can reduce the required transmitter power by up to 13 dB compared to single-ele ment receivers. In non-LOS links, imaging receivers and multibeam transmitt ers can reduce the required transmitter power by more than 20 dB. Furthermo re, we discuss the use of multibeam transmitters and imaging receivers to i mplement space-division multiple access (SDMA). In a representative example with two users. transmitting at a power sufficient to achieve a BER not ex ceeding 10(-9) with 95% probability in the absence of cochannel interferenc e, when SDMA is employed, the system can achieve a BER not exceeding 10(-9) with a probability of about 88%.