Phase Offset Transmission Polarization for HSDPA MIMO Interference
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Solution Overview
Problem
Legacy HSDPA devices experience performance degradation due to concurrent HSDPA-MIMO traffic, particularly with Virtual Antenna Mapping (VAM) techniques, which fail to maintain optimal power balancing and throughput for non-MIMO users.
Innovation Solution
Applying an additional phase offset to one physical path to adapt transmit polarization, optimizing phase differences between transmit chains dynamically based on Channel Quality Information (CQI) to maximize throughput for legacy HSDPA devices while maintaining MIMO performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Virtual Antenna Mapping (VAM) is used to support concurrent HSDPA and MIMO traffic, then MIMO performance is improved, but HSDPA throughput deteriorates due to power imbalance and interference
Solution Approach 1:
The patent dynamically adjusts the phase offset parameter between transmit chains to optimize HSDPA performance while maintaining MIMO functionality. By changing the phase relationship between antenna ports, the system modifies the effective polarization and interference characteristics, thereby improving HSDPA throughput without sacrificing MIMO capabilities
Solution Approach 2:
The system transitions from static power allocation to dynamic phase-based power balancing. The phase offset between transmit chains is adjusted in real-time based on channel conditions and traffic requirements, enabling the system to adaptively optimize performance for both HSDPA and MIMO users concurrently
2Quantity of substance
If power is allocated to MIMO transmit chains, then MIMO capacity increases, but power balancing for non-MIMO users deteriorates
Solution Approach 1:
Instead of changing power allocation parameters, the patent changes the phase parameter to achieve power balancing. By adjusting the phase offset between transmit chains, the system maintains equal power distribution across antenna ports while still supporting MIMO capacity, thereby resolving the power balancing issue without reducing MIMO throughput
3Productivity
If phase offset is applied to adapt transmit polarization, then HSDPA throughput is improved, but system complexity increases
Solution Approach 1:
The patent introduces a single phase offset parameter that can be applied through simple phase rotation in the signal processing chain. This parameter change requires minimal additional hardware or processing complexity compared to more sophisticated power allocation or beamforming schemes, making it an efficient solution for improving HSDPA throughput
Solution Approach 2:
The phase offset adjustment is applied locally to specific transmit chains rather than requiring system-wide reconfiguration. This localized parameter adjustment allows the system to optimize HSDPA performance in specific cell sectors or transmit paths without affecting the entire network infrastructure, thereby minimizing overall system complexity
Data Source
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AI summary
Method and system for improving the performance of mobile communication networks. The method and system employs the additional functionality whereby an additional phase offset can be applied to one of the physical paths (one physical antenna) in order to modify and adapt the transmit polarization. In the preferred embodiment, the criterion for selecting the additional phase offset will be to maximize the energy received from the HSPA serving cell by the legacy HSDPA user equipments.