Adaptive equalization for 100 Mbps OWSS wireless LANs

OWSS: A new signaling system for 100-150 Mb/s wireless LANs

“…±3, ±5, ±7}. Since the above SE appears to be surprisingly low, we performed a theoretical cross-check, as discussed in [3]. The theoretical analysis indeed reinforces the effectiveness of the adaptive equalizer.…”

“…It deploys an FE and a DFE, both of finite impulse response (FIR) form [3]. Not shown is the adaptation mechanism, which will not be discussed here but can be found in [3]. The receiver also uses a correlator, a decision device, and an upsampler.…”

“…Results of a 64-QAM 108 Mb/s OWSS system over an indoor multipath channel, with a maximum Doppler frequency of 5 Hz, are shown in Fig. 5a [3]. The channel model is a 14-tap complex I Figure 4.…”

“…Some of the advantages realized [1,2] are: • Single or multiple user capability • Inherent frequency diversity for overcoming frequency selective fading • Continuously pipelined operation (in contrast to OFDM) • High bandwidth efficiency, which is about twice that for direct sequence code-division multiple access (DS-CDMA), assuming rectangular chips for DS-CDMA To effectively mitigate frequency selective multipath fading, equalization at the receiver is still needed. The OWSS receiver uses a forward equalizer (FE) and a decision feedback equalizer (DFE), together with the Least Mean Squares (LMS) algorithm for adaptation [3]. Theory as well as simulation experiments on a 108 Mb/s 64quadrature amplitude modulated (QAM) OWSSbased system over an indoor multipath channel with a maximum Doppler frequency of 5 Hz show that a low bit error rate (BER) can be achieved even without channel coding [3].…”

“…The OWSS receiver uses a forward equalizer (FE) and a decision feedback equalizer (DFE), together with the Least Mean Squares (LMS) algorithm for adaptation [3]. Theory as well as simulation experiments on a 108 Mb/s 64quadrature amplitude modulated (QAM) OWSSbased system over an indoor multipath channel with a maximum Doppler frequency of 5 Hz show that a low bit error rate (BER) can be achieved even without channel coding [3]. Furthermore, it is found that the OWSS system passband spectrum is quite compact.…”