Distributed Antenna Transmission Scheduling via Clear Channel Indication
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In distributed antenna systems (DAS), existing methods for scheduling user equipment (UE) transmissions do not account for the UE's position, leading to inefficient use of antennas, increased interference, and complex network requirements, particularly when operating on unlicensed spectra.
Innovation Solution
A method where a base station in a DAS stores state information for each antenna indicating whether it should be in a transmit or do_not_transmit state, determines clear channel indications, and adjusts these states based on transmission success, ensuring that only antennas with successful clear channel assessments are used for data transmission to the UE.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If scheduling is performed without taking into account UE position in DAS, then device complexity is reduced, but network capacity and performance deteriorate due to increased interference
Solution Approach 1:
The system segments the DAS antennas into multiple groups, where each group is associated with specific coverage areas. The base station maintains position information that maps UEs to appropriate antenna groups, enabling selective scheduling that reduces interference while maintaining manageable complexity through organized segmentation of the antenna resource pool.
Solution Approach 2:
The base station pre-acquires and stores position information about UEs and their corresponding coverage areas before scheduling decisions are made. This preliminary action enables the scheduler to quickly identify suitable antenna groups based on pre-computed position data, avoiding complex real-time calculations while improving scheduling efficiency and reducing interference.
2Object-affected harmful factors
If CCA is performed on all antennas in unlicensed spectrum, then interference is reduced, but device complexity and operational complexity increase
Solution Approach 1:
The system applies different CCA requirements to different antenna groups based on their local characteristics and coverage areas. Antennas serving areas with high interference perform CCA, while antennas in areas with naturally lower interference or different radio conditions may have relaxed or waived CCA requirements. This local differentiation reduces overall system complexity while maintaining interference management where most needed.
Solution Approach 2:
Instead of requiring CCA on all antennas, the system performs CCA only on a subset of antennas that are most likely to cause or experience interference based on their coverage areas and current traffic conditions. This partial action approach reduces the burden of universal CCA while still providing adequate interference management through selective application to critical antenna groups.
3Ease of operation
If antennas are selected without considering coverage area, then ease of operation is improved, but reliability deteriorates due to failed transmissions
Solution Approach 1:
The base station pre-acquires and stores position information that maps each UE to its coverage area and corresponding suitable antenna groups before transmission attempts. This preliminary positioning and mapping action enables the scheduler to make reliable antenna selections based on pre-computed spatial relationships, ensuring that selected antennas are actually within range of the target UE and will likely succeed in delivering transmissions.
4Device complexity
If rudimentary CCA solutions are implemented, then device complexity is reduced, but reliability deteriorates due to retransmissions and radio link failure
Solution Approach 1:
The system segments antennas into groups with associated coverage area information, enabling the scheduler to select from multiple suitable antenna groups rather than relying on a single rudimentary CCA result. This segmentation provides redundancy and alternatives, so if one antenna group fails, the scheduler can try another group covering the same UE, thereby improving reliability without significantly increasing overall system complexity.
Solution Approach 2:
The system incorporates feedback mechanisms where the base station monitors transmission outcomes and uses position information to adjust future scheduling decisions. When transmissions fail, the system can reference stored position data to identify alternative antenna groups that should have been selected, learning from past failures to improve future reliability while maintaining relatively simple operational procedures.
Data Source
Figure 1(A)~1(B)
Figure 2
Figure 3
AI summary
A method includes a base station in a distributed antenna system having a set of antennas. For each antenna, the base station stores state information indicating that the antenna is either in a transmit state or a do_not_transmit state. For each antenna indicated by the state information for the antenna as being in the transmit state, the base station determines whether the antenna has been given a clear channel indication (CCI) for a next transmission time interval (TTI). At the next TTI, the base station transmits data to a UE, wherein the base station transmits the data to the UE using antennas included in said set of antennas that i) are indicated by the state information for the antenna as being in the transmit state and ii) have been given the CCI. The base station adjusts the state information in accordance with a transmit status.