Base Station Control Channel Mapping for LTE Cat.0
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Solution Overview
Problem
The existing communication systems, particularly in LTE, face challenges in efficiently mapping and reporting the radio resource amount used for the L1/L2 control channel, leading to potential throughput and coverage degradation due to unclear transmission intervals and positions of Cat.0 information in the time-frequency domain.
Innovation Solution
A base station apparatus and communication control method that effectively reports the radio resource amount used for the control channel by employing specific signal processing components and multiplexing schemes, including frequency block assignment, scheduling, and subcarrier mapping, to optimize the transmission of Cat.0 information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If Cat.0 information is transmitted every TTI with fixed format, then control channel dimensioning is supported, but mapping positions in time-frequency domain are unclear leading to throughput degradation
Solution Approach 1:
The patent segments the control channel information into Cat.0 information (transmitted every TTI) and other control information, with each having distinct mapping positions in the time-frequency domain. This segmentation allows Cat.0 information to be reliably transmitted for dimensioning while other information can be optimized for throughput, resolving the contradiction between adaptability and productivity.
Solution Approach 2:
The patent introduces explicit mapping position information in the vertical dimension (time domain) by specifying which OFDM symbols contain Cat.0 information. This dimensional specification clarifies the time-frequency mapping positions, enabling both reliable dimensioning support and optimized throughput by preventing resource conflicts.
2Adaptability or versatility
If Cat.0 information is transmitted every TTI, then control channel flexibility is improved, but overhead increases due to repeated transmission
Solution Approach 1:
The patent extracts Cat.0 information as a separate, standardized component that is transmitted every TTI in fixed positions, while other control information is transmitted in remaining resources. This extraction reduces overhead by preventing duplication of Cat.0 information in every control message and allows efficient resource utilization.
3Reliability
If control channel resources are increased, then coverage is improved, but frequency resource usage increases reducing system capacity
Solution Approach 1:
The patent applies local quality by assigning specific OFDM symbols (e.g., first and second symbols) exclusively to Cat.0 information transmission. This localized allocation ensures reliable coverage for control information in critical time slots while leaving other frequency resources available for data transmission, maintaining system capacity.
Data Source
AI summary
A base station apparatus used in a mobile communication system to which an OFDM scheme is applied in downlink is provided with: a scheduler configured to perform assignment of radio resources to a user apparatus for each subframe; a control channel generation unit configured to generate a control channel for reporting a result of scheduling by the scheduler to the user apparatus; and a mapping unit configured to map the control channel and a data channel, wherein the control information includes information indicating a radio resource amount used for the control channel, and the mapping unit multiplexes information indicating the radio resource amount used for the control channel into a first OFDM symbol.