Relay Node DRS Discovery via Duplex Capability
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Solution Overview
Problem
In wireless communications systems, relay nodes face inefficiencies and increased latency during inter-relay discovery due to interference between discovery reference signals (DRSs) transmitted simultaneously by multiple nodes, which hinders the detection of additional nodes for wireless backhaul connections.
Innovation Solution
Relay nodes transmit a capability report to a parent node indicating their duplexing capability, allowing the parent node to configure DRS transmission and measurement resources. Half-duplex nodes are configured for non-overlapping resources, while full-duplex nodes can transmit and receive simultaneously, optimizing DRS transmission and measurement times to reduce interference and enhance discovery efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple relay nodes transmit DRSs simultaneously, then discovery procedures can be performed in parallel, but the DRSs interfere with one another resulting in failed detection
Solution Approach 1:
The patent implements periodic DRS transmission with configured time windows and periodicity parameters. Relay nodes transmit DRSs at specific periodic intervals rather than continuously or randomly, which organizes the discovery process in structured time periods and reduces random interference between simultaneous transmissions from different nodes.
Solution Approach 2:
The patent segments the discovery process by dividing relay nodes into different groups based on their cell global identifiers (CGIs). Each group is assigned specific time windows for DRS transmission, so that not all nodes transmit simultaneously. This segmentation based on CGI modulo operation creates distinct transmission cohorts that reduce inter-node interference while maintaining parallel discovery capabilities.
2Productivity
If a relay node transmits a DRS at the same time as another node, then resource utilization is maximized, but the first node cannot receive the DRS from the other node increasing latency
Solution Approach 1:
The patent implements dynamic time window allocation where relay nodes can be configured with different DRS transmission time windows based on their group assignments. Full-duplex capable nodes are dynamically assigned to overlap their transmission and measurement windows, allowing them to transmit and receive simultaneously. Half-duplex nodes are dynamically assigned non-overlapping windows, preventing self-interference. This dynamic configuration optimizes resource utilization while managing latency through appropriate window timing.
Solution Approach 2:
The patent changes the timing parameters of DRS transmission and measurement windows based on duplexing capability. Full-duplex nodes are configured with overlapping time windows (transmission window overlaps with measurement window), while half-duplex nodes are configured with non-overlapping windows. This parameter change in window timing allows full-duplex nodes to utilize simultaneous transmit-receive capability, maximizing resource utilization without incurring the latency penalty that would affect half-duplex nodes.
3Reliability
If half-duplex relay nodes use non-overlapping DRS transmission and measurement resources, then interference is avoided, but discovery process requires more time
Solution Approach 1:
The patent applies periodic DRS transmission with configured time windows and periodicity parameters. Half-duplex relay nodes transmit DRSs in specific time windows and measure DRSs from other nodes in subsequent measurement windows within each periodic cycle. This structured periodic approach ensures reliable separate transmit-receive operations while containing the time overhead within defined periodic intervals rather than extending discovery indefinitely.
4Loss of time
If full-duplex relay nodes use simultaneous DRS transmission and measurement resources, then discovery latency is reduced, but self-interference may occur
Solution Approach 1:
The patent changes the timing parameters of DRS transmission and measurement windows based on duplexing capability. Full-duplex nodes are configured with overlapping time windows (transmission window overlaps with measurement window), while half-duplex nodes are configured with non-overlapping windows. This parameter change in window timing allows full-duplex nodes to utilize simultaneous transmit-receive capability, maximizing resource utilization without incurring the latency penalty that would affect half-duplex nodes.
Data Source
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AI summary
Methods, systems, and devices for wireless communications are described. Some wireless communications systems may implement an integrated access and backhaul (IAB) network architecture where relay nodes connect with other IAB nodes via wireless backhaul links. For improved node discovery, during or after an initial relay integration procedure with a parent node, a relay node may transmit a capability report to the parent node indicating a duplexing capability of the relay node (e.g., whether the relay node is half-duplex or full-duplex capable). Based on the duplexing capability, the parent node may determine discovery reference signal (DRS) transmission and measurement resources for the relay node and configure the relay node with these resources. The relay node may use these resources for transmitting DRSs and monitoring for DRSs from other IAB nodes. If the relay node discovers another IAB node in the network, the nodes may form a wireless backhaul link.