Distributed Antenna Scheduling With Invisibility Vector
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Solution Overview
Problem
Existing MU-MIMO systems in telecommunication networks face inefficiencies in resource scheduling due to inter-user interference, particularly in Distributed Antenna Systems, where user equipment may not detect signal strengths from all Remote Radio Units, leading to suboptimal resource allocation and reduced network efficiency.
Innovation Solution
A method that involves calculating an invisibility vector to account for signal attenuation, allowing the Base Station to weight quantization vectors and schedule transmissions based on actual signal reception, using Channel Quality Information and Channel Direction Information to optimize resource allocation and reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing precoding schemes (CVQ or PU2RC) are used for spatial user separation, then multiple users can be served simultaneously on the same subcarrier, but inter-user interference cannot be effectively reduced because the Base Station assumes all RRU signals are received by the UE even when signal attenuation is deep
Solution Approach 1:
The patent introduces a feedback mechanism where the User Equipment explicitly indicates which RRUs are visible to it by setting bits to 1 in the codebook index feedback. This feedback allows the Base Station to accurately identify which RRUs should be included in the precoding matrix, resolving the contradiction between maintaining high throughput and ensuring accurate resource scheduling by adapting to actual signal reception conditions.
Solution Approach 2:
The patent changes the parameter representation from traditional codebook indices to a modified codebook index format that includes visibility information. By transforming the feedback parameter to indicate RRU visibility status, the system can dynamically adjust the precoding matrix construction based on actual channel conditions, thereby improving both throughput and scheduling accuracy simultaneously.
2Ease of manufacture
If the Base Station schedules transmissions assuming all RRU signals are received, then scheduling can be performed using standard precoding schemes, but resources are not efficiently allocated when signal attenuation causes some RRUs to be undetectable
Solution Approach 1:
The patent performs preliminary action by having the User Equipment pre-indicate its visible RRUs before the actual transmission scheduling. This preliminary visibility indication allows the Base Station to construct an accurate precoding matrix in advance, ensuring that only detectable RRUs are used for scheduling, thereby improving resource allocation efficiency while maintaining implementation simplicity through standard codebook mechanisms.
3Measurement precision
If quantization channel vectors are used for precoding, then spatial user separation can be achieved, but the system cannot distinguish between different RRU signal strengths when they are under UE sensitivity threshold
Solution Approach 1:
The patent extracts the critical visibility information from the complex channel state feedback and incorporates it directly into the codebook index representation. By extracting and emphasizing the RRU visibility status (detectable vs. undetectable signals), the system achieves accurate channel quality detection without requiring complex signal processing, as the visibility information is directly provided by the UE's feedback mechanism.
Data Source
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AI summary
A method of scheduling a signal transmission to a user equipment in a transmitter system, said transmitter system comprising a plurality of spatially distributed transmitters for transmitting signals to said user equipment and a base station for controlling said plurality of spatially distributed transmitters, said method comprising, for said base station, the acts of obtaining for the user equipment a quantization vector estimating the state of the channel between the transmitter system and the user equipment, obtaining for the user equipment a weighting factor representing an attenuation of the channel between the user equipment and at least one of the plurality of spatially distributed transmitters, and scheduling a signal transmission to the user equipment using the obtained quantization vector weighted with the obtained weighting factor.