E-PHICH Allocation for Uplink HARQ in Multi-Node Wireless Systems
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Solution Overview
Problem
In wireless communication systems, especially multi-node systems, the existing control channels are insufficient for smooth Hybrid Automatic Repeat Request (HARQ) operations as the number of supported terminals increases, leading to inefficiencies in ACK/NACK signal transmission.
Innovation Solution
The method involves allocating additional radio resources and using Enhanced-PHICH (E-PHICH) in conjunction with PHICH for ACK/NACK signal transmission, where E-PHICH is allocated to specific OFDM symbols within a subframe, allowing for efficient HARQ performance even with a higher number of terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing control channels are used for ACK/NACK transmission in multi-node systems, then system structure remains simple, but the channels become insufficient when the number of terminals increases
Solution Approach 1:
The control channel resources are segmented into two distinct types: traditional PHICH resources and enhanced E-PHICH resources. This segmentation allows the system to maintain the original simple PHICH structure for basic operations while introducing additional E-PHICH resources specifically for multi-node system operations, thereby increasing support capacity without completely redesigning the existing control channel structure
Solution Approach 2:
The patent introduces E-PHICH as an additional dimension of control channel resources beyond the traditional PHICH. By allocating E-PHICH resources to specific OFDM symbols subsequent to those used by PHICH, the system expands the control channel capacity in the time-frequency domain, enabling support for more terminals while maintaining the original PHICH structure
2Reliability
If more radio resources are allocated for ACK/NACK transmission, then HARQ performance improves, but radio resource consumption increases
Solution Approach 1:
Instead of uniformly increasing control channel resources across the entire system, the patent applies local quality by allocating E-PHICH resources to specific local regions in the time-frequency domain (specific OFDM symbols). This localized resource allocation provides additional HARQ capacity where needed in multi-node systems while conserving radio resources in other areas, thus improving HARQ reliability without proportionally increasing overall resource consumption
Data Source
AI summary
Provided are a method and an apparatus for a terminal performing uplink HARQ in a multi-node system comprising a plurality of nodes and a base station, which is connected to and can control each of the plurality of nodes. The method comprises the following steps: receiving information on control channel allocation from the base station; transmitting uplink data to at least one node from the plurality of nodes; and receiving from the at least one node an acknowledgement/not-acknowledgement (ACK/NACK) signal with respect to the uplink data, based on the information on the control channel allocation.