Wireless Positioning Subframes with Varying Reference Signal Sequences
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Solution Overview
Problem
Current wireless communication systems face challenges in achieving effective interference averaging for user equipment positioning, particularly in indoor environments, due to the limitations of existing reference signal periodicity and positioning subframe configurations, which result in suboptimal channel estimation and positioning accuracy.
Innovation Solution
The proposed solution involves setting a prescribed periodicity for the reference signal and positioning subframe that is disjoint or differently aligned with the generation periodicity of the reference signal, allowing for interference diversity gain through varying the sequence of the reference signal in each positioning subframe, thereby enhancing the signal-to-interference ratio and positioning accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the reference signal sequence is repeated with the same periodicity in positioning subframes, then the system structure is simple, but interference averaging is ineffective and positioning accuracy is poor
Solution Approach 1:
The patent applies dynamics by making the reference signal sequence vary dynamically across different positioning subframes rather than repeating the same sequence. The sequence is determined by a formula that incorporates the subframe number, causing each positioning subframe to have a different sequence. This dynamic variation enables effective interference averaging while maintaining manageable system complexity through mathematical formulation.
Solution Approach 2:
The patent utilizes periodic action by establishing a periodic transmission pattern for positioning subframes (e.g., every 10ms, 20ms, or 30ms) while varying the sequence within each period. This combines periodicity with sequence variation, allowing the system to maintain regular timing for positioning measurements while introducing diversity through different sequences in each period.
2Reliability
If the reference signal sequence is varied in each positioning subframe, then interference averaging is improved, but the system complexity increases
Solution Approach 1:
The patent applies parameter changes by systematically varying the reference signal sequence based on changing parameters (subframe number, cell identifier). Instead of using fixed or random sequences, the sequence is determined by a formula that changes parameters in a controlled manner. This approach improves interference averaging reliability while keeping the complexity manageable through deterministic parameter-based variation.
Solution Approach 2:
The patent uses copying by generating different sequence copies for different positioning subframes based on a master sequence pattern. Each positioning subframe receives a copied and modified version of the base sequence, where the modification is determined by the subframe index and cell identity. This copying approach enables sequence diversity without requiring completely independent sequence generation for each subframe.
3Productivity
If positioning subframes are transmitted frequently, then positioning updates are more frequent, but interference averaging opportunity is reduced
Solution Approach 1:
The patent resolves this contradiction through dynamics by enabling frequent positioning subframe transmissions while simultaneously varying the reference signal sequence dynamically. The sequence variation mechanism works effectively regardless of transmission frequency, allowing the system to transmit positioning subframes frequently for high update rates while the varying sequences provide sufficient diversity for interference averaging to maintain accuracy.
Data Source
AI summary
The present invention relates to a wireless communication system, and more particularly, to an apparatus for positioning a user equipment and method thereof. The present invention includes receiving, from a plurality of base stations including a serving cell, a predetermined number of consecutive positioning subframes in a radio frame at a predetermined period, each of the consecutive positioning subframe including a reference signal, measuring a time of arrival of the positioning subframes by using the reference signal, and transmitting a result of the measured time of arrival of the positioning subframe to the serving cell, wherein the predetermined period is set to be larger than a generation period of the reference signal and wherein sequences of the reference signals included in the consecutive positioning subframes are different from each other.