Radio Relay Node Subframe Segmentation for Interference Reduction
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Solution Overview
Problem
In LTE radio communication systems, relay nodes face interference issues when simultaneously transmitting and receiving data, which complicates the scheduling of control and payload data, particularly due to the need for signal isolation and the limitations of existing control signaling formats.
Innovation Solution
The proposed solution involves dividing the downlink subframe into an early part for time-critical control data and a later part for less time-critical data, such as uplink grants, allowing for efficient scheduling of payload data in unused resources and reinterpreting existing DCI formats to exclude R-PDCCH regions from data reception, thereby reducing interference and improving throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If relay nodes simultaneously transmit and receive data, then throughput is improved, but interference increases requiring signal isolation
Solution Approach 1:
The patent divides the downlink subframe into two distinct parts: an early part for time-critical control data and a later part for less time-critical data such as uplink grants. This segmentation allows the relay node to receive control information in the early part without interference from its own transmissions, while still enabling data transmission in the later part, thus resolving the contradiction between maintaining throughput and avoiding self-interference.
2Loss of time
If control signaling is transmitted at the beginning of each subframe, then control latency is reduced, but resources for payload data are limited
Solution Approach 1:
By segmenting the subframe into early and later parts, the patent allows control signaling to be transmitted at the beginning (early part) to minimize control latency, while simultaneously preserving resources in the later part for payload data transmission. This resolves the contradiction by showing that proper temporal segmentation can satisfy both low control latency and adequate payload resources.
Solution Approach 2:
The patent utilizes the time dimension by transmitting different types of data (control vs. payload) at different times within the same subframe. This temporal dimensionality change allows both control and payload data to coexist without competing for the same resources, resolving the resource limitation issue while maintaining low control latency.
3Device complexity
If existing DCI formats are used without modification, then implementation complexity is reduced, but flexibility in scheduling is limited
Solution Approach 1:
The patent introduces dynamic interpretation rules for existing DCI formats based on the timing of R-PDCCH transmission. When R-PDCCH is transmitted in the early part, the corresponding DCI format is interpreted as scheduling downlink data; when transmitted in the later part, it is interpreted as scheduling uplink grants. This dynamic interpretation provides scheduling flexibility while reusing existing DCI formats, thus resolving the contradiction between low complexity and high adaptability.
Data Source
AI summary
The present invention generally relates to radio communication systems, relay nodes, controller nodes, user equipment (user terminals), software and methods for said systems and nodes. In one embodiment, a method for operating a control node for a wireless communication system is provided. The method comprises the steps: creating a data frame comprising an early part and a later part, wherein the early part comprises first control data for controlling a receiving node; checking whether second control data are to be put into the later part; scheduling payload data for the receiving node into the later part if second control data are not to be put into the later part; and transmitting the data frame to the receiving node.