Distributed MIMO Access Point Grouping for Wide-Area Broadcast
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Solution Overview
Problem
Distributed massive MIMO systems lack effective techniques for wide-area broadcast transmissions, particularly in 5G New Radio, where reliable and efficient transmission of system information and control data is necessary without channel state information, and existing methods like beam-sweeping and single-frequency network broadcasting are inefficient or unreliable.
Innovation Solution
The method involves using a hybrid diversity scheme combining space-time block coding and access point hopping, where access points are grouped into different sets for alternating antenna port mappings in even and odd slots, providing spatial diversity against small-scale fading and macro-diversity, and utilizing space-time-frequency block codes like Alamouti codes for robust wide-area transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If beam-sweeping is performed to improve SNR for users within beam coverage, then signal-to-noise ratio is improved, but resource consumption for broadcasting increases
Solution Approach 1:
The access points are divided into different groups that transmit on different frequencies simultaneously. This segmentation allows the system to provide beam-sweeping coverage to multiple users at once without requiring all access points to consume resources for every user, thereby improving SNR for targeted users while reducing overall resource consumption through parallel transmissions.
2Reliability
If multi-cell broadcasting in single-frequency network fashion is used to provide macro-diversity, then coverage reliability is improved, but delay spread and small-scale fading increase
Solution Approach 1:
The invention changes the frequency parameter by having different groups of access points transmit on different frequencies simultaneously. This frequency diversity approach provides macro-diversity coverage similar to single-frequency network broadcasting, but avoids the harmful effects of delay spread and small-scale fading that occur when all access points transmit on the same frequency.
3Reliability
If distributed antenna systems are deployed to coordinate interference and mitigate shadow fading, then network reliability is improved, but system complexity increases
Solution Approach 1:
The system employs periodic time slots where different groups of access points are activated in an alternating pattern. This periodic activation scheme allows distributed antenna systems to coordinate interference and mitigate shadow fading effectively, while reducing system complexity by not requiring all access points to be simultaneously active and managed, thus lowering the operational complexity compared to continuous full-system operation.
4Speed
If wide-area transmissions are performed without channel state information for ultra-reliable low-latency applications, then transmission speed is improved, but transmission reliability decreases
Solution Approach 1:
The invention changes the frequency parameter by transmitting the same data block on multiple different frequencies simultaneously through different access point groups. This frequency diversity approach enables wide-area transmissions without requiring channel state information acquisition, maintaining ultra-reliable low-latency performance while improving transmission reliability through frequency diversity that mitigates fading and interference effects.
Data Source
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AI summary
A method (200) of transmitting a block of data in a distributed MIMO system is disclosed. The distributed MIMO system comprises a plurality of access points (A 1,..., A K), wherein access points (A j) are grouped into a first set of M groups and a second set of M groups, different from the first set, wherein M is an integer. A first antenna port mapping assigns each group of the first set to a unique one of M antenna ports. A second antenna port mapping assigns each group of the second set to a unique one of M antenna ports. The method comprises transmitting (220) the block of data using both the first and the second antenna port mapping.