PHICH Resource Allocation in LTE Wireless Systems
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Solution Overview
Problem
The 3GPP LTE wireless communication networks lack a defined mapping function for Physical Hybrid Automatic Repeat Request Indicator Channel (PHICH) group provisioning and signaling, particularly for time division duplex (TDD) and frequency division duplex (FDD modes, which affects PHICH resource allocation and power management.
Innovation Solution
A method is introduced to determine the number of PHICH groups in a downlink subframe based on system bandwidth and a scaling factor, using equations that account for different duplex modes, allowing for dynamic PHICH resource signaling and power allocation between PHICH and Physical Downlink Control Channel (PDCCH) resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PHICH resource allocation is increased to improve HARQ ACK/NACK signaling reliability, then coverage and performance are enhanced, but system bandwidth and power resources are consumed
Solution Approach 1:
The patent introduces a scaling factor parameter that dynamically adjusts the number of PHICH groups based on system bandwidth and traffic conditions. By changing this parameter, the system can optimize PHICH resource allocation to achieve reliable HARQ ACK/NACK signaling while adapting power consumption to actual network conditions, thus resolving the contradiction between reliability and energy usage.
Solution Approach 2:
The patent enables dynamic PHICH resource allocation where the number of PHICH groups is not fixed but can be adjusted based on system bandwidth and scaling factors. This dynamic approach allows the system to allocate more PHICH resources when reliability is critical and reduce resources when conditions permit, balancing reliability requirements with power consumption constraints.
2Productivity
If PHICH groups are increased to support more uplink transmissions, then system capacity is improved, but device complexity and resource management difficulty increase
Solution Approach 1:
The patent defines specific parameters including system bandwidth and scaling factors that control PHICH group allocation. By using these parameters, the system can calculate appropriate PHICH resources through defined relationships, transforming a complex resource management problem into a parameter-driven calculation that improves system capacity while managing complexity through standardized parameter relationships.
Solution Approach 2:
The patent applies different scaling factors and allocation rules based on specific system conditions such as bandwidth size and duplex mode (TDD or FDD). This local quality approach allows the system to optimize PHICH allocation for different operating conditions without requiring a completely different resource management scheme for each scenario, thus improving capacity while controlling complexity through context-specific parameter adjustment.
3Reliability
If PHICH resource indicator Nh is increased to provide more PHICH groups, then signaling coverage is improved, but signaling overhead and resource element consumption increase
Solution Approach 1:
The patent uses the 2-bit PHICH resource indicator Nh as a controllable parameter that selects from predefined PHICH group configurations. By adjusting this parameter based on system bandwidth and scaling factors, the system can achieve adequate signaling coverage while controlling the number of resource elements consumed, as the parameter directly controls the mapping between PHICH groups and resource elements in the control region.
Data Source
AI summary
A wireless communication terminal and method for determining a number of Physical Hybrid ARQ Indicator Channel (PHICH) groups (N) in the downlink subframe based on a first parameter, a second parameter and a determined cyclic prefix (CP) duration, wherein the first parameter indicates a downlink system bandwidth in terms of a number of resource blocks and the second parameter indicates a scaling factor. The terminal receives downlink control signaling in a set of resource elements in the subframe, wherein the set of resource elements is determined based partly on the number of PHICH groups (N).