Downlink Control Signaling With Type 2 Resource Allocation
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Solution Overview
Problem
Existing methods to improve PDCCH capacity are difficult to implement, occupy PDSCH resources, and reduce air interface usage efficiency, particularly in LTE-A systems where terminal devices in transmission modes TM 7, TM 8, TM 9, and TM 10 demodulate PDSCH based on DMRS, leading to resource shortages and inefficient DCI transmission.
Innovation Solution
A downlink control information transmission method that utilizes a newly defined DCI format indicating resource positions based on resource allocation type 2, reducing the bit usage for DCI scheduling in PDCCH without occupying PDSCH resources, applicable to terminal devices in transmission modes TM 7, TM 8, TM 9, and TM 10, without requiring support for ePDCCH.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If ePDCCH is used to carry DCI, then PDCCH capacity is improved, but device complexity increases and implementation becomes difficult
Solution Approach 1:
The patent changes the resource allocation parameter from type 0/type 1 to type 2, which fundamentally alters how resource positions are indicated in DCI. This parameter change reduces the bit length of DCI without requiring new physical channel structures like ePDCCH, thereby improving PDCCH capacity while avoiding increased device complexity
Solution Approach 2:
The patent makes terminal devices capable of both receiving DCI indicating resource allocation type 0/type 1 and DCI indicating resource allocation type 2. This multi-functionality allows the same DCI structure to serve multiple purposes across different transmission modes, improving capacity without requiring separate specialized structures
2Quantity of substance
If ePDCCH is used to carry DCI, then PDCCH capacity is improved, but PDSCH resources are occupied and air interface usage efficiency decreases
Solution Approach 1:
The patent extracts the resource allocation indication function from the PDSCH and places it directly in the DCI on PDCCH. By taking out the resource allocation type 2 indication method and applying it to DCI formatting, the patent eliminates the need to occupy PDSCH resources for control information, thereby improving both PDCCH capacity and air interface usage efficiency
Solution Approach 2:
The patent transitions from indicating resource positions through PDSCH resource occupation to indicating resource positions through DCI bit fields. This dimensional change moves the control information from the data channel dimension to the control channel dimension, freeing up PDSCH resources for data transmission
3Adaptability or versatility
If DCI in format 1 with resource allocation type 0 or 1 is used, then transmission modes TM 7-10 are supported, but DCI bit length increases and PDCCH resources are insufficient
Solution Approach 1:
The patent changes the resource allocation parameter from type 0/type 1 to type 2 in DCI format 1, which fundamentally reduces the bit length required for resource position indication. This parameter change maintains support for transmission modes TM 7-10 while reducing DCI size, thereby improving PDCCH capacity
Solution Approach 2:
The patent applies resource allocation type 2, which uses a more compact representation method, to the DCI structure. This partial action of using a more efficient encoding method for resource allocation reduces the overall DCI bit length without sacrificing the ability to indicate resource positions for transmission modes TM 7-10
Data Source
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AI summary
This application provides a downlink control information transmission method and an apparatus. A network device determines that a terminal device is in the first transmission mode in which the terminal device demodulates a PDSCH based on a DMRS. The network device sends a first PDSCH and first DCI to the terminal device. The first DCI includes a first field. The first field indicates, based on a resource allocation type 2, a resource position occupied by the first PDSCH. The terminal device may demodulate the first PDSCH at the resource position indicated by the first field. An existing DCI format indicates a resource position based on a resource allocation type 0 or a resource allocation type 1. The first DCI indicates a resource position based on the resource allocation type 2. A quantity of used bits of a resource position indication manner based on the resource allocation type 0 or the resource allocation type 1 is greater than a quantity of used bits of a resource position indication manner based on the resource allocation type 2. Therefore, the method can reduce a quantity of used bits of a PDCCH occupied by DCI without occupying a PDSCH resource.