Base Station Random Access Resource Allocation in LTE Carrier Aggregation
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Solution Overview
Problem
In LTE and LTE-A wireless communication systems, when a base station allocates multiple uplink and downlink carrier components to a mobile station, the physical downlink control channel cannot indicate the specific radio resource for random access, leading to ambiguity in which downlink carrier component instructs the start of the random access procedure.
Innovation Solution
The system introduces a method where the base station broadcasts information about the paired uplink and downlink carrier components, including the configuration of the physical random access channel, allowing the mobile station to determine the correct random access resource by receiving the physical downlink control channel on any one of the allocated downlink carrier components, ensuring that the mobile station can identify the random access resource corresponding to the specific downlink carrier component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple uplink and downlink carrier components are allocated to a mobile station, then the data communication capacity is improved, but the physical downlink control channel cannot indicate the specific radio resource for random access, causing ambiguity
Solution Approach 1:
The patent divides the downlink carrier components into two types: first downlink carrier components that can be used for random access procedure, and second downlink carrier components that cannot be used for random access procedure. This segmentation allows the base station to clearly indicate which carrier component should be used for random access, resolving the ambiguity while maintaining multiple carrier component allocation for improved data communication capacity.
2Productivity
If multiple carrier components are used, then the system capacity is improved, but the complexity of determining the correct random access resource increases
Solution Approach 1:
The patent applies different properties to different downlink carrier components: first downlink carrier components are configured with random access capability, while second downlink carrier components are not. This local differentiation simplifies the mobile station's determination process by allowing it to identify the correct random access resource based on the carrier component type, rather than having to analyze multiple possibilities across all carrier components.
Data Source
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AI summary
A mobile station apparatus (1) determines an uplink carrier component to which a physical downlink control channel instructing to start random access procedure corresponds. Provided is a wireless communication system in which a base station apparatus (3) and a mobile station apparatus (1) communicate with each other using a plurality of component carriers, wherein the base station apparatus (3) includes a random access controller (1012) that preliminarily allocates random access resources corresponding to a specific downlink component carrier, by means of which the mobile station apparatus (1) can start a random access communication, and a transmission processor (111) that transmits control information instructing to start the random access procedure, and wherein the mobile station apparatus (1) includes a random access processor (2012) that, upon receipt of the control information instructing to start the random access procedure, starts the random access procedure by means of the random access resource corresponding to a specific downlink component carrier preliminarily allocated by the base station apparatus (3).