Control Channel Modulation Switching for LTE Resource Optimization
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Solution Overview
Problem
The capacity of control channels in LTE/LTE-Advanced systems is limited due to technologies like MIMO and CoMP, leading to inefficient resource utilization and high overhead in control signaling, especially when using higher eCCE aggregation levels.
Innovation Solution
A method to determine an effective coding rate for control channels based on the length of control information and the number of resource elements, switching between QPSK and 16QAM modulation depending on the coding rate threshold, with the threshold set according to channel quality information, to reduce resource element usage and improve downlink resource utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a higher eCCE aggregation level is used to send the E-PDCCH when the effective coding rate is extremely high, then the control channel can be transmitted, but the overhead of control signaling increases and downlink resource utilization rate decreases
Solution Approach 1:
The patent dynamically changes the modulation order parameter based on the effective coding rate. When the effective coding rate exceeds a threshold, the system switches from QPSK (modulation order 2) to higher-order modulation (modulation order ≥4), which changes the number of resource elements required for transmission and reduces control signaling overhead while maintaining reliability
2Quantity of substance
If all REs in an RB pair are used to transmit control information, then the control channel capacity is maximized, but the resource utilization becomes inefficient when multiple UEs share the same RB pair
Solution Approach 1:
The patent applies local quality by allowing different modulation orders for different control channels within the same RB pair. Each control channel can be modulated according to its specific effective coding rate and channel conditions, optimizing resource usage locally rather than uniformly across all control channels
3Adaptability or versatility
If the size of eCCEs is adjusted to match varying numbers of available REs in different subframes, then the mapping consistency is improved, but the modulation method cannot be determined for cases with extremely high effective coding rates
Solution Approach 1:
The patent introduces dynamic modulation order selection based on the effective coding rate. The modulation order is not fixed but dynamically adjusted according to channel conditions and effective coding rate, allowing the system to adapt to varying eCCE sizes and available REs while providing a clear determination criterion for modulation methods
Data Source
AI summary
The present invention provides a control channel modulation and demodulation method, a base station, and a user equipment, where the control channel modulation method includes: determining, according to a length of control information borne on a control channel and the number of resource elements occupied by the control channel, an effective coding rate that is at the time when a first modulation manner is used to modulate the control channel; and modulating the control channel by using a second modulation manner when the effective coding rate is greater than a first threshold. In the present invention, sending of the control channel can be completed by using less resource elements, thereby reducing overhead of control signaling and further improving a downlink resource utilization rate.