CCE+ Number Allocation for LTE and LTE+ Coexistence
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Solution Overview
Problem
In a mixed system where LTE and LTE+ communication systems coexist, the efficiency of frequency use deteriorates due to separate control channels, leading to potential ACK/NACK collisions when the LTE+ system uses the same frequency as the LTE system, limiting the amount of information that can be transmitted and causing collisions in transmission resources.
Innovation Solution
The LTE+ system allocates CCE+ numbers differently from LTE CCE numbers by increasing the size of CCE+ to 54 REs, ensuring that CCE+ numbers do not overlap with LTE CCE numbers, preventing collisions by selecting distinct numbers for PDCCH+ and PDCCH allocation, and interleaving CCE and CCE+ allocations on a per REG basis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate control channels are provided for LTE and LTE+ systems, then each system can operate independently, but frequency efficiency deteriorates and ACK/NACK collisions occur
Solution Approach 1:
The patent merges the control channels of LTE and LTE+ systems into a shared frequency resource. By allowing both systems to use the same frequency band for control information transmission, the patent improves frequency efficiency while implementing separation mechanisms (different CCE number allocations) to prevent collisions and maintain system independence.
2Productivity
If the same frequency is used for both LTE and LTE+ control channels, then frequency efficiency improves, but ACK/NACK collisions occur due to overlapping CCE numbers
Solution Approach 1:
The patent applies local quality by differentiating the CCE number allocation scheme between LTE and LTE+ systems. While both systems share the same frequency resource, the LTE+ system uses a modified CCE number allocation (starting from a different offset or using a different mapping rule) compared to the LTE system. This local differentiation in the allocation quality ensures that CCE numbers do not overlap, preventing ACK/NACK collisions while maintaining high frequency efficiency.
3Quantity of substance
If CCE+ size is increased to 54 REs, then the amount of control information that can be transmitted increases, but the complexity of resource allocation increases
Solution Approach 1:
The patent changes the parameter of CCE+ size from the standard LTE size to 54 resource elements (REs). This parameter change enables the LTE+ system to transmit more control information within the same time-frequency resources. The patent manages the resulting allocation complexity by implementing a systematic CCE number allocation scheme that accounts for the larger size, ensuring that resources are efficiently assigned without excessive complexity.
Data Source
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AI summary
Disclosed is a CCE+ number allocation method which reduces the ACK/NACK (Acknowledgment/Negative Acknowledgment) collision probability in a mixed system containing an LTE (Long Term Evolution) system and an LTE+ (Long Term Evolution Advanced) system. A CCE(Control Channel Element)+ number is defined by selecting a number from CCE numbers of the CCE to contain PDCCH (Physical Downlink Control Channel) allocated in a resource element region constituting CCE+ where PDCCH + is arranged. This can prevent overlapped selection of the CCE number and the CCE + number even when the PDCCH and the PDCCH+ are simultaneously transmitted. Thus, it is possible to reduce the collision probability of ACK/NACK correlated to the CCE number and the CCE+ number.