MU-MIMO Shared Pilot Signal Generation via Precoding Vectors
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Solution Overview
Problem
In MU-MIMO systems, as the number of data streams increases, allocating a dedicated pilot signal to each UE results in high pilot overheads, and sharing a pilot signal among UEs leads to interference, preventing correct data stream acquisition.
Innovation Solution
A method where a base station determines a shared pilot signal and precoding vector for multiple UEs, ensuring the pilot precoding vector is orthogonal to other UEs' channels, allowing each UE to receive a unique data stream without interference, by calculating the pilot precoding vector and data stream receiving gain based on downlink channel information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a different dedicated pilot signal is allocated to each UE, then each UE can correctly obtain its data stream without interference, but pilot overheads increase as the number of data streams increases
Solution Approach 1:
The patent merges multiple dedicated pilot signals into a single shared pilot signal that is transmitted once and reused by multiple UEs. The base station generates one pilot signal that contains information for multiple UEs, and each UE uses its specific precoding vector to extract the required channel information from this shared pilot, thereby reducing pilot overhead while maintaining reliable data stream acquisition.
Solution Approach 2:
The shared pilot signal serves multiple functions simultaneously - it provides channel estimation information for multiple UEs transmitting on the same time-frequency resource. By designing the pilot signal to be universally applicable to multiple UEs through the use of precoding vectors, the system eliminates the need for separate dedicated pilot signals for each UE.
2Quantity of substance
If a same pilot signal is allocated to multiple UEs to reduce pilot overheads, then pilot overhead is reduced, but each UE is interfered by pilot signals of other UEs, preventing correct data stream acquisition
Solution Approach 1:
The patent segments the shared pilot signal processing by introducing UE-specific precoding vectors. While the pilot signal itself is shared and unsegmented in transmission, each UE applies its dedicated precoding vector to process the received pilot signal, effectively segmenting the channel estimation process. This allows multiple UEs to use the same pilot signal without interference, as each UE's precoding vector orthogonally separates its channel information from others.
Solution Approach 2:
The patent changes the parameter space by introducing precoding vectors as an additional dimension for differentiation. Instead of using different pilot signals (time/frequency domain separation), the system uses precoding vectors (spatial domain parameters) to enable multiple UEs to share the same pilot signal while maintaining orthogonal channel estimation paths, thus eliminating interference.
3Productivity
If the number of parallel data streams is increased, then system throughput is improved, but pilot overheads increase when dedicated pilot signals are allocated to each UE
Solution Approach 1:
The patent merges the pilot signaling resources for multiple data streams into a single shared pilot transmission. By combining what would traditionally require multiple separate pilot signals into one shared pilot that serves multiple UEs simultaneously, the system enables increased parallel data streams without the proportional increase in pilot overhead that would normally accompany higher throughput requirements.
Data Source
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AI summary
Embodiments of the present invention relate to the field of communications technologies, and provide a pilot signal generation method and apparatus, so as to implement sharing of one pilot by multiple UEs when it is ensured that each of the multiple UEs can correctly obtain a data stream, thereby reducing pilot overheads. The method includes: determining a first pilot signal shared by multiple UEs, where the multiple UEs are multiple UEs transmitting data streams on a same time-frequency resource; determining a pilot precoding vector of first UE and a data stream receiving gain of the first UE according to current downlink channel information of the multiple UEs, where the first UE is one of the multiple UEs; and generating, according to the first pilot signal, the data stream receiving gain of the first UE, and the pilot precoding vector of the first UE, a second pilot signal that is to be sent to the first UE. The method is applied to an MU-MIMO system.