Vertical adaptive antenna array for a discrete multitone spread spectrum communications system
AssigneeAT&T Wireless Services, Inc.
InventorsSiavash Alamouti, Joel E. Becker, Douglas Frank Stolarz
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Abstract
Two or more antenna elements are arranged in the vertical direction to give vertical spatial adaptivity to a wireless discrete multitone spread spectrum communications system. The system is based on a combination of Discrete Multitone Spread Spectrum (DMT-SS) and multi-element adaptive antenna array technologies. This enables the automatic positioning of a beam in the vertical direction to position nulls where interferers are located on the same azimuth but are separated in elevation.
Claims24
A highly bandwidth-efficient communications method, comprising:
- receiving a received spread signal at a base station having a multi-element antenna array with a first plurality of antenna elements arranged in a spaced vertical direction and a second plurality of antenna elements arranged in a spaced horizontal direction;
- said received spread signal comprising a first data signal spread over a plurality of discrete tones in accordance with a remote spreading code assigned to a remote unit for a first time period;
- adaptively despreading the signal received at the base station by using first despreading codes that are based on the characteristics of the received signals at the first plurality of antenna elements of said array and perform vertical beam steering;
- adaptively despreading the signal received at the base station by using second despreading codes that are based on the characteristics of the received signals at the second plurality of antenna elements of said array to perform horizontal beam steering;
- and
- receiving at the base station during an initialization period, a pilot spread signal comprising a known data signal spread over a plurality of discrete tones.
A highly bandwidth-efficient communications system comprising:
- means for receiving a received spread signal at a base station having a multi-element antenna array with a first plurality of antenna elements arranged in a spaced vertical direction and a second plurality of antenna elements arranged in a spaced horizontal direction;
- said received spread signal comprising a first data signal spread over a plurality of discrete tones in accordance with a remote spreading code assigned to a remote unit for a first time period;
- means for adaptively despreading the signal received at the base station by using first despreading codes that are based on the characteristics of the received signals at the first plurality of antenna elements of said array and perform vertical beam steering;
- said despreading means adaptively despreading the signal received at the base station by using second despreading codes that are based on the characteristics of the received signals at the second plurality of antenna elements of said array to perform horizontal beam steering;
- and
- means for spreading a second data signal at the base station with first spreading codes derived from said first despreading codes, that distributes the second data signal over a plurality of discrete tones and the first plurality antenna elements of said array, forming a first spectrally spread signal that is spectrally and spatially spread vertically.
Dependencies are inferred from the claim text.