PHICH Resource Allocation for NCT Demodulation
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Solution Overview
Problem
The existing PHICH structure in LTE networks faces challenges with demodulation using DM-RS on NCT, reliability of UL data transmission for low-cost UE, PHICH resource allocation conflicts in small cells, and transmission reliability in unauthorized spectrum carriers, particularly due to limitations in resource allocation and interference coordination.
Innovation Solution
A method involving dividing ACK/NACK information into groups, performing joint coding, and mapping these groups to predetermined physical resources, including ePDCCH and PDSCH, using specific time and frequency domain resources, and DM-RS ports to enhance transmission reliability and resource allocation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional PHICH structure is used on NCT, then CRS-based demodulation is maintained, but DM-RS-based demodulation required for NCT cannot be achieved
Solution Approach 1:
The PHICH structure is segmented into multiple PHICH groups, each associated with specific DM-RS ports. This allows the system to support multiple demodulation reference signal types simultaneously, enabling NCT to use DM-RS while maintaining compatibility with traditional CRS-based operations on other carriers.
Solution Approach 2:
The patent introduces a new dimension to PHICH resource allocation by associating PHICH groups with DM-RS ports in the antenna domain. This dimensional extension allows the same PHICH structure to serve both traditional CRS-based and new DM-RS-based demodulation requirements without conflict.
2Quantity of substance
If PHICH resources are allocated for multiple terminals, then ACK/NACK coverage is improved, but resource allocation conflicts occur in small cells
Solution Approach 1:
Different PHICH groups are assigned to different small cells with locally optimized resource allocations. Each small cell can configure its PHICH groups independently according to local traffic conditions and interference patterns, eliminating resource allocation conflicts while maintaining high ACK/NACK capacity.
Solution Approach 2:
The PHICH resource allocation is made dynamic through configurable parameters such as numberOfPHICHGroups and phichResourceConfig, allowing the system to adapt resource distribution in real-time based on changing network conditions, terminal densities, and interference levels in different small cells.
3Productivity
If PHICH is multiplexed with PDCCH in same control resource, then resource efficiency is improved, but interference between channels increases
Solution Approach 1:
The PHICH and PDCCH are merged in the time-frequency domain through resource element multiplexing, where PHICH occupies specific REs within PDCCH resource blocks. This merging achieves high resource efficiency by eliminating separate allocations while maintaining distinguishable signal structures through orthogonal codes and resource element patterns.
Solution Approach 2:
Orthogonal codes and resource element patterns act as intermediaries between PHICH and PDCCH, enabling their coexistence in the same control resources. These intermediaries provide separation mechanisms that reduce mutual interference while allowing efficient joint utilization of control channel resources.
Data Source
AI summary
Provided are methods for sending and receiving ACK/NACK information, a base station, and a terminal, wherein the method for sending ACK/NACK information includes that ACK/NACK information of a plurality of terminals is divided into X groups according to a preset indication parameter, wherein X is a positive integer greater than or equal to 1; joint coding is performed on ACK/NACK information corresponding to each group in the X groups, so as to obtain X first bit blocks; and the X first bit blocks are mapped to a predetermined ACK/NACK physical resource and sent. By means of the disclosure, reliable transmission of HARQ-ACK information of a terminal on an NCT is implemented, the reliability of transmission of UL data in a Low Cost terminal is improved, and problems such as a conflict of PHICH resource allocation and ICIC of a frequency domain in a small cell are solved.