Multi-RAT Resource Scheduling via Shared PDCP Entity
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Solution Overview
Problem
In wireless communication systems where multiple radio access technologies (RATs) coexist, such as LTE and Wi-Fi, efficient radio resource scheduling across different base stations becomes challenging, particularly when these stations are separated and backhaul support is not ideal, leading to difficulties in coordinating radio resource management for multi-flow aggregation in the downlink.
Innovation Solution
The system coordinates multiple base stations of different RATs by maintaining a single upper protocol layer entity and different lower protocol layer entities for each RAT, allowing radio bearers to be configured across both, with the terminal performing measurements and sending reports to determine the most suitable RAT for data transmission, enabling efficient resource scheduling through shared PDCP entities and independent RLC/MAC layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple base stations of different RATs are used for simultaneous communication, then data transmission capacity and bandwidth are improved, but coordination complexity and resource scheduling difficulty increase
Solution Approach 1:
The protocol stack is segmented into common upper layers (PDCP and above) that are shared across multiple RATs, and separate lower layers (RLC/MAC/PHY) that are RAT-specific. This segmentation allows independent optimization of each RAT while maintaining unified management at higher layers, reducing coordination complexity despite having multiple base stations.
Solution Approach 2:
The PDCP layer and upper protocol layers serve multiple functions across different RATs simultaneously. A single PDCP entity can handle data for multiple radio bearers that are multiplexed over different RATs, enabling one structure to perform multiple functions and reducing overall system complexity.
2Adaptability or versatility
If separate lower protocol layer entities are maintained for each RAT, then RAT-specific optimization is achieved, but entity management complexity increases
Solution Approach 1:
The protocol architecture is divided into common upper layers (PDCP and above) that are shared across multiple RATs, and separate lower layers (RLC/MAC/PHY) that are RAT-specific. This segmentation allows independent optimization of each RAT while maintaining unified management at higher layers, reducing coordination complexity despite having multiple base stations.
Solution Approach 2:
Multiple RAT-specific lower layer entities are merged under a single common upper layer entity (PDCP). The PDCP layer receives data from multiple RLC entities corresponding to different RATs and handles them uniformly, reducing the management burden compared to having completely separate entities for each RAT.
3Device complexity
If a single common upper protocol layer entity is used for multiple RATs, then coordination and resource scheduling are simplified, but RAT-specific protocol requirements may be compromised
Solution Approach 1:
The protocol stack is segmented into common upper layers (PDCP and above) that are shared across multiple RATs, and separate lower layers (RLC/MAC/PHY) that are RAT-specific. This segmentation allows independent optimization of each RAT while maintaining unified management at higher layers, reducing coordination complexity despite having multiple base stations.
Solution Approach 2:
The PDCP layer acts as an intermediary between the RAT-specific lower layers and the common upper layers. It receives data from multiple RLC entities corresponding to different RATs, applies necessary RAT-specific processing, and then handles the data uniformly at the PDCP layer and above, thus bridging the gap between protocol diversity and unified management.
Data Source
AI summary
A scheme for the co-ordination of multiple base stations of different RATs (radio access technologies), such as a LTE eNB, UMTS base station, and WiFi access point with the assistance of the terminals in order to achieve efficient radio resource scheduling for multi-RAT multi-flow aggregation in the downlink. At the network side, multi-RAT flows (RB11) share the same PDCP Entity, (PDCP Entity) while each has independent RLC/MAC (RAT1 RLC Entity, RAT2 RLC Entity). The terminal (UE1) performs necessary measurements on all involved RATs, depending on the requirements of different RATs, and sends measurement reports/indication to all involved base stations. Based on the measurement report as well as pre-defined rules/policy, a decision is made on which RAT should be used for next DL transmission or next period of DL transmission.