Selective Pilot Transmission for 4Tx MIMO Demodulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In multi-antenna wireless communication systems, particularly in 4Tx MIMO transmissions, the use of additional pilots for data demodulation can negatively impact legacy UEs by reducing the energy available for HS-PDSCH scheduling and causing interference, while minimizing these pilots to reduce impact on legacy UEs adversely affects the demodulation performance of 4Tx UEs.
Innovation Solution
A radio network node selectively transmits additional pilots for data demodulation based on parameters such as channel quality, location, and modulation rate, ensuring that common pilots are sufficient for lower ranks and rates, and additional pilots are provided only when high data rates with high ranks are scheduled, thereby optimizing pilot power usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional pilots are transmitted for data demodulation in 4Tx MIMO, then demodulation performance is improved, but energy available for HS-PDSCH scheduling is reduced and interference to legacy UEs increases
Solution Approach 1:
The patent applies local quality by differentiating pilot transmission strategies for different UE types: 4Tx UEs receive additional pilots for high-rank demodulation while legacy UEs continue to use common pilots only. This localized optimization ensures that the energy allocation and pilot transmission are tailored to specific receiver capabilities, improving demodulation performance for 4Tx UEs without unnecessarily impacting legacy UE performance.
2Measurement precision
If additional pilots are transmitted for data demodulation in 4Tx MIMO, then channel estimation quality is improved, but interference to legacy terminals increases
Solution Approach 1:
The patent segments the pilot transmission into two distinct types: common pilots transmitted for channel estimation and additional demodulation pilots transmitted specifically for data demodulation. This segmentation allows the system to provide high-quality channel estimates to all UEs through common pilots while enabling 4Tx UEs to utilize additional pilots for enhanced demodulation performance, thereby improving measurement precision without causing harmful interference to legacy terminals that ignore the additional pilots.
3Measurement precision
If additional pilots are transmitted for data demodulation, then data detection capability is enhanced, but pilot power levels for legacy terminals must be reduced
Solution Approach 1:
The patent implements dynamic pilot power allocation where the system adaptively adjusts pilot power levels based on UE capability and channel conditions. For 4Tx UEs requiring high-rank demodulation, additional pilots are transmitted at optimized power levels to enhance data detection capability. For legacy terminals, pilot power levels are maintained at appropriate levels without unnecessary increases, achieving dynamic optimization of power distribution that enhances detection capability where needed while preserving reasonable power levels for legacy compatibility.
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A radio network node (28) comprises a transmitter/receiver (48, 82, 93) configured to communicate over an air interface (32) with a wireless terminal (30); a scheduler (46, 84); and a order signal determination means (46, 62, 84). The scheduler (46, 84) schedules pilot signals, including common pilot signals transmitted for channel estimation, for transmission over the air interface to the wireless terminal. The order signal determination means (46, 62, 84)is configured to make a selective determination whether additional pilot signals for data demodulation are also to be transmitted to the wireless terminal (30) in addition to the common pilot signals transmitted for the channel estimation. The wireless terminal (30) comprises a transmitter and receiver (50, 101, 112) and pilot selection means (68). The pilot selection means (68) is configured to make a determination regarding which pilot signals transmitted by the radio network node are to be utilized by the wireless terminal. The pilot signals transmitted by the radio network node include common pilot signals transmitted for channel estimation and additional pilot signals transmitted for data demodulation.