| 摘要 |
<p>AN APPARATUS AND METHOD FOR COMMUNICATING DATA BETWEEN AT LEAST TWO DATA DEVICES (20, 22), SUITABLE FOR USE AS A WIRELESS LOCAL-AREA NETWORK THAT PROVIDES ROBUST DATA COMMUNICATION VIA A RADIO COMMUNICATIONS CHANNEL CORRUPTED BY MULTIPATH (26, 28) INTERFERENCE, PARTICULARLY AT HIGH DATA RATES. A PREFERRED EMBODIMENT OF THE INVENTION REPRESENTS DATA AS A SEQUENCE OF WALSH-FUNCTION WAVEFORMS (FIGS. 15A - H) ENCODED BY PSEUDO-NOISE DIRECT-SEQUENCE SPREAD-SPECTRUM MODULATION. WALSH-FUNCTION- ENCODING OF THE DATA PROVIDES A LONG SYMBOL DURATION, THEREBY ALLOWING THE SPREAD- SPECTRUM MODULATION TO PROVIDE PROCESSING GAIN SUFFICIENT TO SUBSTANTIALLY OVERCOME MULTIPATH INTERFERENCE, WHILE PROVIDING A HIGH DATA RATE. IN ANOTHER PREFERRED EMBODIMENT, WALSH-FUNCTION MODULATION IS SUPPLEMENTED WITH VARIOUS FORMS OF PHASE MODULATION, SUCH AS COHERENT PSK FOR HI-ORTHOGONAL SIGNALLING, AND DPSK BETWEEN ORTHOGONAL SYMBOLS FOR NONCOHERENT HI-ORTHOGONAL SIGNALLING, THEREBY FURTHER INCREASING DATA RATE WITHOUT REDUCING PROCESSING GAIN. IN ANOTHER PREFERRED EMBODIMENT, WALSH-FUNCTION MODULATION IS SUPPLEMENTED WITH SPECTRAL SHAPING TO ALLOW INCREASED BANDWIDTH OCCUPANCY, THEREBY FURTHER INCREASING THE PROCESSING GAIN WITHOUT SACRIFICING DATA RATE. (FIG.8)</p> |
