Encoding Cell ID in Unused DCI Bits for Cross-Scheduled Random Access
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Solution Overview
Problem
In wireless communication networks, particularly in LTE systems, existing technologies face challenges in efficiently managing random access procedures across multiple cells, especially in carrier aggregation scenarios, where identifying the correct cell for random access preamble transmission is cumbersome due to limitations in the physical downlink control channel random access order format.
Innovation Solution
The solution involves encoding the identification of the cell on which a user equipment shall transmit a random access preamble into unused bit positions of the physical downlink control channel random access order, allowing for cross-scheduled random access orders, thereby enabling the transmission of this information within the existing control channel format without increasing the number of blind decodings or modifying the DCI Format 1A.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the physical downlink control channel random access order format is extended to include cell identification, then the ability to schedule random access across multiple cells is improved, but the complexity of the control channel format and the number of blind decodings increases
Solution Approach 1:
The patent applies multi-functionality by enabling the existing physical downlink control channel random access order format to serve dual purposes: traditional single-cell random access scheduling and cross-cell random access scheduling. By utilizing unused bit positions in the existing format, the system can encode cell identification information without creating a completely new format, thus achieving cross-cell capability while maintaining compatibility with existing UE implementations.
Solution Approach 2:
The patent changes the parameter utilization of the control channel format by repurposing unused bit positions (such as redundancy version and transmit power control bits) to carry cell identification information. This parameter reuse approach allows the system to extend functionality without increasing the overall format size or requiring additional blind decodings, as the same physical downlink control channel structure is used.
2Adaptability or versatility
If the physical downlink control channel random access order format is extended to include cell identification, then the ability to schedule random access across multiple cells is improved, but the number of blind decodings increases
Solution Approach 1:
The patent ensures that the enhanced random access order format can be decoded by existing user equipment without requiring additional blind decodings. The same physical downlink control channel structure and decoding procedures are used, but the format now supports both traditional and cross-cell scheduling by utilizing unused bit positions, thereby maintaining productivity while achieving extended functionality.
Solution Approach 2:
The system leverages the self-service capability of existing control channel decoding mechanisms by embedding cell identification information within the existing format structure. The unused bit positions are repurposed to carry additional information that can be extracted during the normal blind decoding process, eliminating the need for separate or additional decoding operations.
3Adaptability or versatility
If existing control channel formats are modified to support cross-cell random access, then cross-cell scheduling is enabled, but backward compatibility with existing LTE releases is reduced
Solution Approach 1:
The patent maintains backward compatibility by designing the enhanced random access order format to be universally applicable across different LTE releases. The same physical downlink control channel structure is used, and the unused bit positions are repurposed to carry cell identification information. This ensures that existing user equipment can decode the format without modification, while the system gains cross-cell scheduling capability.
Solution Approach 2:
The patent performs preliminary action by pre-defining how unused bit positions should be interpreted when carrying cell identification information. This preliminary specification ensures that the format enhancement is transparent to existing systems and that backward compatibility is maintained, as the changes are made in a way that does not affect the fundamental structure or decoding process of the control channel.
Data Source
AI summary
A node of a wireless network includes processor circuitry that is configured to obtain an identification of a cell on which a user equipment shall transmit a random access preamble and to encode the identification of the cell on which the user equipment shall transmit the random access preamble into at least one unused bit position of a physical downlink control channel random access order. A transmitter is responsive to the processor circuitry and is configured to transmit the physical downlink control channel random access order including the identification of the cell that was encoded into the at least one unused bit position of the physical downlink control channel random access order. Related user equipment, systems and methods are also described.