Enhanced Control Channel Aggregation and Modulation
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Solution Overview
Problem
The spectral efficiency of control information transmissions in telecommunications systems is not efficient enough, particularly in scenarios with favorable downlink channel conditions and small DCI payloads, leading to unnecessary control overhead and resource waste.
Innovation Solution
Implementing an enhanced Control Channel (eCCH) with a smaller CCE aggregation level than the smallest CCE aggregation level of a physical downlink control channel (PDCCH) and using higher order modulation, such as 16QAM, to reduce the number of resources needed for transmission, while maintaining a low code rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the smallest CCE aggregation level of PDCCH is used, then the control channel transmission is reliable, but the spectral efficiency is limited to 2 bits/RE and resource overhead increases
Solution Approach 1:
The patent introduces a new CCE aggregation level (AL=1/2) that is smaller than the traditional smallest PDCCH aggregation level (AL=1). This parameter change in the control channel structure, combined with higher order modulation (16QAM instead of QPSK), enables spectral efficiency to exceed 2 bits/RE while maintaining transmission reliability through the enhanced resource element group mapping scheme.
2Productivity
If higher order modulation than QPSK is used, then the spectral efficiency improves beyond 2 bits/RE, but the system complexity increases
Solution Approach 1:
The patent applies higher order modulation (16QAM) locally to the enhanced control channel transmissions rather than system-wide. The network node determines whether to use higher order modulation based on specific conditions (favorable downlink channel conditions, small DCI payloads), applying the more complex modulation only where it provides benefit, thus limiting the increase in system complexity.
3Quantity of substance
If smaller CCE aggregation level is used, then the number of resources required for transmission is reduced, but the code rate must be maintained at low levels
Solution Approach 1:
The patent employs dynamic resource allocation where the network node flexibly adjusts the CCE aggregation level and modulation order based on current channel conditions and payload size. This dynamic approach allows the system to use smaller aggregation levels (reducing resource consumption) when conditions permit, while automatically adapting to maintain appropriate code rates by switching between different aggregation levels and modulation schemes.
Data Source
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AI summary
A method in a network node for transmitting an enhanced Control CHannel, eCCH, to a user equipment in a telecommunications system. The eCCH comprises control information to the user equipment in at least one Control Channel Element, CCE. The at least one CCE maps to a number of resource elements comprised in at least one enhanced resource element group. The at least one enhanced resource element group is comprised in at least one resource block in a time-frequency Orthogonal Frequency Division Multiplexing, OFDM, grid. The network node decides to use a CCE aggregation level that is smaller than the smallest CCE aggregation level of a physical downlink control channel, PDCCH, for a first eCCH. The network node then modulates the first eCCH by using a higher order modulation than Quadrature Phase Shift Keying, QPSK, modulation, when the smaller CCE aggregation level is used for the first eCCH. Then, the network node maps the modulated first eCCH to the at least one enhanced resource element group of resource elements in the at least one resource block, and transmits the mapped first eCCH to the user equipment. A network node, a method in user equipment and a user equipment are also provided.