PRS Design for Network-Based Positioning in OFDMA Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current network-based positioning mechanisms in 4G wireless communication systems require multiple ranging signal transmissions, consume excessive power and bandwidth, and suffer from interference issues, which can lead to inaccurate positioning that fails to meet E-911 requirements.
Innovation Solution
A network-based positioning mechanism where a target UE transmits a positioning reference signal (PRS) to both the serving BS and cooperative BSs simultaneously, allowing for TOA measurements to be conducted by multiple BSs with reduced radio resource consumption and interference, using either explicit or implicit positioning schemes and optimized PRS design to minimize radio resources and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple ranging signal transmissions are used for TOA measurement, then positioning coverage is improved, but power consumption and bandwidth consumption increase
Solution Approach 1:
The patent combines multiple ranging signal transmissions into a single positioning reference signal (PRS) transmission. The target UE transmits one PRS that is simultaneously received by multiple base stations (serving BS and neighboring BSs), eliminating the need for separate transmissions to each BS. This merging approach maintains positioning accuracy while significantly reducing power consumption and bandwidth usage.
Solution Approach 2:
The positioning reference signal (PRS) serves multiple functions simultaneously: it enables TOA measurement at the serving base station, provides TDOA measurement capability for multiple neighboring base stations, and supports positioning calculations at both network-based and UE-based locations. This multi-functionality replaces the need for multiple dedicated ranging signals.
2Measurement precision
If multiple ranging signal transmissions are used for TOA measurement, then positioning coverage is improved, but system bandwidth consumption increases
Solution Approach 1:
The patent merges multiple ranging signal transmissions into a single PRS transmission in the time-frequency domain. The PRS is transmitted once and received by multiple base stations simultaneously, reducing bandwidth consumption from multiple separate transmissions to a single shared transmission that serves all positioning purposes.
3Measurement precision
If ranging signal is transmitted to one base station, then TOA measurement can be performed, but interference from neighboring base stations degrades positioning accuracy
Solution Approach 1:
The patent applies preliminary anti-action by having neighboring base stations transmit muted signals or avoiding transmission in the same time-frequency resources where the target UE transmits its PRS. This pre-emptive measure prevents interference before it occurs, ensuring clean PRS reception for accurate TOA measurement at all participating base stations.
4Measurement precision
If more base stations participate in positioning, then positioning accuracy is improved, but radio resource consumption increases
Solution Approach 1:
The patent merges the positioning measurements from multiple base stations into a single PRS transmission event. Instead of requiring separate transmissions for each BS, the system uses one PRS that all participating BSs (serving and neighboring) can receive and measure simultaneously, allowing more BSs to participate without proportionally increasing resource consumption.
Data Source
AI summary
A network-based positioning mechanism is proposed. A serving BS first allocates radio resource to a target UE for network-based positioning in a wireless communication system. The target UE then transmits a positioning reference signal (PRS) to the serving BS and a plurality of cooperative BSs at the same time instant. All the cooperative BSs then conduct PRS detection and TOA measurements. Finally, the serving BS conducts positioning estimation based on the TOA measurement results. In one novel aspect, only one PRS transmission is required in one positioning opportunity for one positioning result. Candidates of PRS are selected with respect to different scenarios and allocated in a PRS resource region. Multiple positioning opportunities and multiple reference signals may be multiplexed over time, frequency or code domain in the PRS resource region. In one embodiment, the PRS is configured in such a way that both radio resource consumption and interference is minimized.