PHICH Allocation for SU-MIMO Uplink Reference Signals
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Solution Overview
Problem
Current LTE systems face limitations in channel capacity and assignment methods for uplink data transmission using Single-User Multiple Input Multiple Output (SU-MIMO) based on multiple codewords, particularly in the allocation of Physical Hybrid Automatic Repeat Request Indicator Channels (PHICH) and generation of reference signals.
Innovation Solution
A method for allocating PHICH and generating reference signals in a SU-MIMO system using multiple codewords, which involves adaptive uplink multiple access schemes like clustered SC-FDMA, and advanced signal processing techniques for error detection and interference cancellation, allowing for efficient transmission of control information and data across multiple antennas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If SU-MIMO based on multiple codewords is implemented in uplink transmission, then uplink channel capacity and data transmission efficiency are improved, but PHICH resource allocation complexity and system design difficulty increase
Solution Approach 1:
The patent segments the PHICH resource allocation into distinct components: one PHICH group for common control information and additional PHICH groups for individual codeword acknowledgments. This segmentation allows the system to handle multiple codewords by allocating specific PHICH resources to each codeword, thereby managing complexity through structured division of resources while maintaining high uplink channel capacity.
Solution Approach 2:
The patent introduces a new dimension in PHICH resource allocation by utilizing codebook-based precoding matrices and associating PHICH groups with specific codeword indices. This dimensional approach allows the system to accommodate multiple codewords in the uplink by mapping each codeword to dedicated PHICH resources, effectively resolving the complexity issue while preserving enhanced channel capacity.
2Reliability
If multiple PHICH groups are allocated for multiple codewords, then acknowledgment coverage for all codewords is improved, but downlink control channel overhead increases
Solution Approach 1:
The patent implements a universal PHICH structure where the first PHICH group serves common control functions for all codewords, while subsequent PHICH groups are dynamically allocated to specific codewords based on transmission needs. This multi-functional approach ensures comprehensive acknowledgment coverage across all codewords while minimizing downlink control channel overhead by activating only the necessary PHICH groups for each transmission scenario.
Solution Approach 2:
The patent dynamically adjusts PHICH resource allocation parameters based on the number of active codewords and channel conditions. By changing parameters such as PHICH group indices, spreading factors, and resource block assignments according to actual transmission requirements, the system achieves complete acknowledgment coverage for multiple codewords while optimizing downlink control channel overhead to match actual needs rather than allocating fixed maximum resources.
3Productivity
If PHICH resource allocation is optimized for SU-MIMO, then transmission efficiency is improved, but compatibility with existing LTE systems deteriorates
Solution Approach 1:
The patent employs dynamic PHICH resource allocation mechanisms that adapt to different transmission modes. The system can dynamically switch between single-codeword and multi-codeword configurations, adjusting PHICH group assignments and resource allocations based on whether SU-MIMO is active. This dynamic behavior optimizes transmission efficiency when SU-MIMO is deployed while automatically maintaining compatibility with existing LTE single-codeword systems when needed.
Solution Approach 2:
The patent introduces intermediary signaling mechanisms and transition protocols that enable smooth operation between legacy LTE modes and enhanced SU-MIMO modes. These intermediaries include configurable parameters, mode indication fields, and gradual deployment strategies that allow the system to maintain backward compatibility while progressively implementing optimized PHICH allocation for SU-MIMO, thereby resolving the compatibility issue without sacrificing transmission efficiency.
Data Source
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AI summary
The present invention relates to a method for generating an uplink reference signal in a system supporting plural uplink-access transmission modes. The method comprises: a step for transmitting the reference signal configuration information about the configuration of a reference signal from a base station to a user device through an uplink grant PDCCH (Physical Downlink Control Channel), and a step for receiving from the user device a sub-frame including the reference signal that is generated based on the reference signal configuration information. The reference signal configuration information is prepared for plural uplink access transmission modes and includes a cyclic shift value for the sequence of the reference signal. The reference signal is supposed to be transmitted to an uplink, and the user device is set up to be operated in the uplink-access transmission mode that corresponding to the reference signal configuration information.