Field trial results for high-speed wireless indoor data communications

Abstract

Abstract-This paper reports on the development of a flexible 5-MBd equalized M-QAM testbed for high-speed wireless data communications. The unit operates in real time and was field tested in typical indoor environments. A total of 3600 independent experiments were conducted using the testbed where one of 4-, 16-, 64-QAM constellations were transmitted, and the performance as a function of adaptive equalization and antenna selection diversity was studied. The experimental results presented here help put previous simulation and analytical results into perspective and demonstrate some of the performance bounds associated with a practical implementation. The field trial results show that with only 10-mW of transmit power, reliable 10-Mbit/s data communication can take place in between rooms with a coverage radius of 17 m, and better than 15% outage at an uncoded bit error rate (BER) of 10 3 . The addition of two-branch antenna selection diversity to the system would allow 10-Mbit/s transmission at better than 3% outage and 20-Mbit/s transmission at 10% outage in the same environment. Moreover, 30-Mbit/s data transmission is feasible when both the transmitter and receiver are located within the same room, albeit at higher outage levels. In general, the results demonstrate the tremendous impact that adaptive equalization can have on the achievable performance of indoor links. Average SNR was improved anywhere from 8 dB to 12 dB depending on the particular environment and data rate. The impact on the outage performance, however, was much more dramatic.

Field measurements of an indoor high-speed QAM wireless system using decision feedback equalization and smart antenna array

“…We observed that the measured BER versus SNR is within 0.5 dB of the theoretical results. This deviation is almost certainly due to the non-Gaussian characteristics of the noise introduced by the quantization, the adaptive algorithms, the recovery loops, and the feedback of errors in the DFE, as illustrated in [19] by using simulations of the prototype system.…”

“…Measurements for the RF units, such as third-order intercept point, introduced intersymbol interference (ISI), and RF power spectrum, were reported in [19]. The RF receiver noise figure was 18 dB at the receiver amplification level selected for the measurements.…”

“…The transmit antenna is a "sleeve" monopole antenna with a nearly omnidirectional beam pattern fabricated in the UCLA Antenna Research, Applications, and Measurement Laboratory. More information on the RF sections and the transmit antenna is available in [19].…”

“…The testbed is fully functional and combines real-time adaptive equalization with a smart antenna array. In [18] and [19], the same research group reported on field trial measurements using a high-speed 5 Mbaud (the unit of baud is defined as "symbols/s") multilevel QAM (M-QAM) equalized wireless testbed. Building on this work, a highly versatile M-QAM testbed system using equalization and a smart antenna array was designed around the DiverQAM chip fabricated at University of California, Los Angeles (UCLA) [20].…”

Visible Light Communications: 170 Mb/s Using an Artificial Neural Network Equalizer in a Low Bandwidth White Light Configuration

“…Alternatively equalization could be used to both increase the data rate as well as remove any ISI [1,[5][6][7][8]. In particular, the decision feedback (DF) equalizer is often selected due to its reasonable performance and ease of hardware implementation [9]. Even though ANNs offer superior performance [10], they have largely been ignored for VLC systems, which is likely due to the difficulties in hardware implementation.…”