Wideband Spatial Division Multiple Access (WSDMA) is a multiple access scheme designed to provide a more stable and effective radio link between the mobile user and the base station. It employs a suite of RF and DSP functions to enhance link performance such as:
Spatial Interference Filtering (SIF)
Digital Signal Processing techniques are employed to tag certain signal sources and to exclude signals arriving from ‘unwanted directions’. In sectors with high usage, where the network is interference limited, the discarding of signals from other zones of the sector results in a step-function improvement in the Signal to Interference Ratio.
The WSDMA enhanced base station can leverage this and instruct the mobile unit to back off its transmit power level, resulting in further improvement to the networks’ self-interference plus the added benefit of increasing handset battery duration.
Sub-Sector/Diversity (SSD) Beamforming
The active array base station system is capable of parallel processing the incoming signals with multiple ‘focussed beams’ overlaid upon a sector-wide beam.
The active array base station system performs ‘multiple focused beam’ processing in parallel with a sector-wide beam. SSD technique combines digital streams to maximise signal quality in direct and multi-path propagation conditions.
Transmit Beam Shaping (TBS)
The added sector spatial awareness produced by the multi-column array structure and other beamforming functionality provides the basis for useful transmit beam shaping actions. The transmit beam may be adjusted periodically using beam shaping (beam width/depth, null creation, sidelobe suppression) and beam steering (pan and tilt combined with sidelobe control).
The initial product will provide for periodic beam adjustment control, based upon sector activity data gathered over time.
Sector Activity Monitoring (SAM)
SAM is an independent digital scanner with related database. The sector scan function completes a sector power sweep of the sector and logs the response over time. The scan detects mobile activity with a high angular resolution.
SAM is an activity data logger with a database which is used for a number of value-generating purposes, real-time or delayed-time,
such as location-based services and network optimisation.
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