E-PDCCH Frequency Diversity for DCI Reliability
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Solution Overview
Problem
The existing LTE-A system lacks a diversity mode for transmitting control information, which limits the capacity and efficiency of the downlink control channel, particularly with the introduction of new technologies like MU-MIMO and CoMP that enhance data transmission but not control channel performance.
Innovation Solution
The method involves determining a plurality of Enhanced Control Channel Elements (E-CCEs) for transmitting Enhanced PDCCH, where each E-CCE includes the same number of Enhanced Resource Elements (E-REGs), each belonging to a different frequency Resource Block, allowing DCI to be diversified across multiple frequency bands for improved stability and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If E-PDCCH uses beam forming transmission mode, then transmission efficiency is improved, but reliability deteriorates under severe inter-cell interference
Solution Approach 1:
The patent implements dynamic switching between beam forming transmission mode and diversity transmission mode based on channel conditions and interference levels. The base station determines the appropriate transmission mode adaptively, allowing the system to transition from beam forming (high efficiency, low interference) to diversity mode (lower efficiency, high interference) to maintain reliable DCI transmission under varying network conditions.
2Productivity
If PDCCH capacity is increased to support more users, then system capacity is improved, but control channel complexity increases
Solution Approach 1:
The patent introduces a new transmission dimension by defining E-PDCCH that operates in the data region rather than the control region, utilizing resource blocks (RBs) instead of traditional CCEs. This dimensional shift allows the system to expand control channel capacity into the data transmission domain, supporting more users and higher aggregation levels without proportionally increasing control channel complexity.
3Productivity
If DCI is transmitted using continuous frequency resources, then transmission efficiency is improved, but resistance to interference deteriorates
Solution Approach 1:
The patent segments DCI transmission across multiple non-contiguous resource blocks in the frequency domain. Instead of using continuous frequency resources, the E-PDCCH distributes control information across multiple separated RBs, which provides frequency diversity and improves resistance to frequency-selective fading and inter-cell interference while maintaining acceptable transmission efficiency.
Data Source
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AI summary
Disclosed are a method and device for transmitting control information, to provide a control information sending manner based on a diversity transmission mode. The method for transmitting control information includes: determining the transmission of a plurality of enhanced control channel units (E-CCE) of an enhanced physical downlink control channel (E-PDCCH), each E-CCE containing the same number of enhanced resource unit groups (E-REGs), and a plurality of E-REGs contained in each E-CCE respectively belonging to a different frequency resource block (RB); and bearing each piece of downlink control information (DCI) to be transmitted over the E-PDCCH into at least one E-CCE for transmission. It is realized that each portion of one piece of DCI is respectively borne onto a plurality of frequency bands corresponding to the E-PDCCH for transmission, improving the stability and reliability of DCI transmission.