HSPA WCDMA Uplink Pilot Signal Pre-coding Weight Segmentation
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Solution Overview
Problem
In HSPA enabled WCDMA systems, existing technologies face challenges in optimizing the transmission and reception of uplink pilot signals, particularly in terms of WCDMA channelization code use, hardware complexity, signaling overhead, interference level, link and system performance, and soft handover operation.
Innovation Solution
A User Equipment (UE) with multiple transmit antennas uses distinct sets of pre-coding weights for transmitting pilot signals, which are also used for data streams, and employs different spreading codes or orthogonal patterns to optimize pilot signal transmission, allowing the NodeB to determine suitable pre-coding vectors for beam forming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If a single pilot signal is transmitted using existing technologies, then the signaling overhead is reduced, but the ability to determine accurate pre-coding vectors for multiple data streams is insufficient
Solution Approach 1:
The patent segments the pilot signal transmission by introducing multiple pilot signals (first pilot signal and second pilot signal) transmitted through different antennas with different pre-coding weights. This segmentation allows the NodeB to separately measure channel conditions for each antenna and data stream, thereby accurately determining pre-coding vectors for multiple data streams while maintaining efficient signaling overhead.
2Measurement precision
If multiple pilot signals are transmitted with different pre-coding weights, then the pre-coding vector determination accuracy is improved, but the WCDMA channelization code use complexity increases
Solution Approach 1:
The patent applies local quality by assigning different pre-coding weights to different pilot signals transmitted from different antennas. Each pilot signal has locally optimized characteristics (different pre-coding weights) that enable the NodeB to accurately determine channel conditions for specific antennas and data streams, thereby improving pre-coding vector determination without requiring complete reconfiguration of the entire WCDMA channelization code structure.
3Adaptability or versatility
If legacy NodeBs are used, then the system compatibility is maintained, but the support for advanced beam forming and multiple data streams is limited
Solution Approach 1:
The patent implements universality by designing a pilot signal transmission mechanism that works with both legacy NodeBs and advanced NodeBs. The UE transmits multiple pilot signals using different pre-coding weights, which legacy NodeBs can process using existing channelization codes, while advanced NodeBs can utilize these signals for sophisticated beam forming and multiple data stream determination, thereby maintaining backward compatibility while enabling advanced capabilities.
Data Source
AI summary
A UE, for an HSPA WCDMA system, equipped with a first and a second transmit antenna, and arranged to use one or more sets of pre-coding weights for transmission. The UE is arranged to receive instructions from a NodeB on the set or sets of pre-coding weights to be used, and to transmit a first and a second pilot signal, and to use a first set of pre-coding weights for the first pilot signal and a second set of pre-coding weights for the second pilot signal, where the first set of pre-coding weights is the same as the UE uses for transmitting a first data stream, and to use different spreading codes for the first data stream and for the first pilot signal.