Multicast Pilot Sequence Assignment for LSAS
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional Large-Scale Antenna Systems (LSAS) are limited in serving a large number of subscribers simultaneously due to the constraint of orthogonal pilot sequences, which is not well-suited for high-density areas, and inefficiently utilize resources for pilot transmission.
Innovation Solution
Assigning unique pilot sequences to each program rather than subscriber units, allowing for composite channel estimation and efficient transmission of multiple subscriber requests, thereby optimizing channel usage and reducing pilot contamination interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If distinct up-link pilot sequences are assigned to each subscriber, then unique channel estimates can be obtained for each terminal, but the maximum number of terminals that can be served simultaneously is limited by the maximum number of orthogonal pilot sequences
Solution Approach 1:
The patent merges multiple subscriber requests for the same program into a single multicast transmission. By identifying that multiple subscribers want to receive the same program, the system combines their channel estimates and transmits one copy of the program to multiple subscribers simultaneously, thereby increasing the number of subscribers served without requiring additional orthogonal pilot sequences for each individual subscriber.
Solution Approach 2:
The patent makes the pilot sequence assignment universal by assigning pilot sequences to programs rather than to individual subscribers. A single pilot sequence can be used by multiple subscribers who are interested in the same program, allowing the system to serve multiple subscribers with the same program request using the same pilot sequence, thus breaking the one-to-one mapping constraint.
2Productivity
If more than half of the coherence interval is spent on pilot transmission, then more subscribers can be served, but this reduces the time available for actual data transmission
Solution Approach 1:
The patent combines channel estimation for multiple subscribers into a single process by merging their pilot sequences. When multiple subscribers request the same program, their pilot sequences are combined and processed together to generate a single composite channel estimate, reducing the total pilot transmission time required while maintaining accurate channel estimation for all subscribers.
3Measurement precision
If conventional unicast transmission is used for each subscriber, then individual channel estimates are obtained, but system throughput is reduced due to redundant transmissions of the same program
Solution Approach 1:
The patent merges multiple unicast transmissions into a single multicast transmission. When multiple subscribers request the same program, the system combines their channel estimates and transmits one copy of the program to all requesting subscribers simultaneously, eliminating redundant transmissions and increasing system throughput while maintaining individual channel estimation accuracy through composite channel estimates.
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
In one embodiment, the method of multicast includes assigning a pilot sequence to each program from among a plurality of programs such that each program has a unique pilot sequence. The method further includes broadcasting the unique pilot sequences for the plurality of programs.