Uplink Beamforming Transmit Diversity for Wireless Devices
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Solution Overview
Problem
Wireless communication systems face limitations in uplink transmit power and interference mitigation, leading to restricted data transmission rates and capacity issues due to maximum transmit power constraints and interference from other users.
Innovation Solution
Implementing uplink beamforming transmit diversity using beamforming weight vectors received by wireless communication devices, which are applied to pilot, data, and control channels to optimize signal-to-noise ratio and reduce interference across multiple antennas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If maximum transmit power is used for uplink data transmission, then data transmission rate is improved, but interference to other cells increases
Solution Approach 1:
The patent applies beamforming to create spatially selective transmission, where different beamforming weight vectors are applied to different spatial directions. This allows the system to concentrate transmit power in the direction of the intended receiver while minimizing power radiation in other directions, thereby reducing interference to other cells. The beamforming weights are calculated based on channel state information to optimize the spatial distribution of transmit power.
Solution Approach 2:
The patent introduces spatial dimensionality to the uplink transmission by using multiple transmit antennas and beamforming. Instead of transmitting in a single dimension (omnidirectional or single antenna), the system exploits the spatial dimension by forming directed beams. This dimensional expansion allows the system to achieve both high data rates through focused transmission and low interference through spatial separation of different user signals.
2Productivity
If beamforming weight vectors are applied to optimize signal-to-noise ratio, then data transmission rate is improved, but transmit power requirements increase
Solution Approach 1:
The patent changes the parameters of the transmitted signal by applying complex beamforming weight vectors that include both amplitude and phase components. These weight vectors are optimized to maximize the signal-to-noise ratio at the receiver while maintaining the total transmit power constraint. The amplitude components of the weights control the power distribution across antennas, and the phase components control the spatial direction of the beams, achieving both high data rates and efficient power utilization.
3Productivity
If multiple pilot channels are transmitted to enable beamforming, then system capacity is improved, but device complexity increases
Solution Approach 1:
The patent implements preliminary channel estimation by transmitting multiple pilot channels before actual data transmission. These pilot channels allow the base station to pre-calculate the channel state information and beamforming weight vectors. By performing this estimation and calculation work in advance, the system enables subsequent high-capacity data transmission without requiring complex real-time processing during the actual data transmission phase, thus managing device complexity effectively.
Data Source
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AI summary
A method and apparatus for enabling uplink beamforming transmit diversity is provided. The method may include receiving, by a wireless communications device (WCD), a beamforming weight vector in response to transmission by the WCD of two or more pilot channels, applying the received beamforming weight vector to at least one of a first of the two or more pilot channels, one or more data channels, or one or more control channels, and transmitting, using two or more antennas, at least one of the one or more data channels or at least one of the one or more control channels, wherein the number of pilot channels is greater than or equal to the number of antennas.