Relay Node Uplink Scheduling via Aggregated Buffer and CQI Reporting
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Solution Overview
Problem
In LTE networks with relay nodes, existing methods for scheduling user equipment (UE) under the control of a relay node (RN) face challenges in optimizing resource allocation due to high control signaling overhead, particularly in conveying buffer status reports (BSR) and channel quality information (CQI) from RNs to the e-NodeB, which is necessary for efficient UL scheduling.
Innovation Solution
The solution involves a method where the RN summarizes and compiles user data volume indications and buffer status reports from UEs into an uplink status report, which includes both actual and virtual buffer information, and sends this report to the e-NodeB, allowing for optimized resource allocation without excessive signaling overhead. Additionally, the RN aggregates and passes UL CQI information to the e-NodeB for scheduling decisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the relay node conveys detailed buffer status reports and channel quality information from each user equipment to the access node, then the scheduling decisions can be optimized, but the control signaling overhead increases significantly
Solution Approach 1:
The patent combines multiple individual buffer status reports from different user equipments into a single aggregated buffer status report at the relay node. Instead of forwarding each UE's BSR separately to the access node, the relay node consolidates this information, significantly reducing the number of signaling messages while preserving the necessary scheduling information for the access node to make optimized decisions.
Solution Approach 2:
The relay node acts as an intermediary between user equipments and the access node. It collects, processes, and summarizes buffer status information and channel quality indicators from multiple UEs, then forwards this aggregated information to the access node. This intermediary function reduces the signaling burden on the access node while maintaining scheduling optimization capabilities.
2Loss of information
If the relay node collects and forwards all user equipment buffer status reports individually, then complete information is available for scheduling, but the latency increases due to multiple transmission steps
Solution Approach 1:
The relay node performs preliminary aggregation and processing of buffer status reports before forwarding them to the access node. By consolidating information from multiple UEs into a single report in advance, the system reduces the number of subsequent transmission steps and minimizes signaling latency while maintaining complete information for scheduling decisions.
Solution Approach 2:
Multiple individual buffer status reports are merged into a single aggregated report at the relay node. This combining process reduces the total number of messages that need to be transmitted to the access node, thereby reducing the cumulative latency associated with multiple separate transmission steps while preserving all necessary scheduling information.
Data Source
AI summary
User equipments UEs send their buffer status reports and data to a relay node RN. The RN stores the data in actual buffers per radio bearer group RBG, and stores the UEs buffer occupancies in virtual buffers per RBG. The RN then sends its own status report to the controlling eNBr with the actual buffer occupancy and information about the virtual buffer occupancy. This enables the eNBr to know in advance the volume of data incoming to the RN's actual buffers, as well as the current occupancy of those buffers, so as to better allocate radio resources. Further, the RN can take soundings of the uplink channels between UEs and the RN, which are then aggregated across the RBRs and sent to the eNBr as a special UL CQI report. The eNBr is thereby enabled to anticipate how soon the data in the UE buffers will appear in the RN's actual buffers (from the additional information of average UL CQI info and virtual buffer status), and thus better allocate the RBRs to be used for the different RBGs in the RN-eNB link as well as the optimal set of RBRs to the UE-RN link, which the RN can redistribute among the UEs that it is serving.