PHICH Group Allocation in TDD Wireless Systems
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently transmitting and receiving control information, particularly in Time Division Duplex (TDD) systems, where determining the number of Physical Hybrid ARQ Indicator Channel (PHICH) groups is complex due to varying uplink-downlink configurations.
Innovation Solution
A method and apparatus for user equipment in a wireless communication system that receives higher and lower layer signals to determine the number of PHICH groups based on specific uplink-downlink configuration information, adjusting the multiple used in PHICH group determination depending on whether the subframe is uplink or downlink, and allocating PHICH resources accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of PHICH groups is determined based on varying UL-DL configurations in TDD systems, then the control information transmission can adapt to different subframe types, but the complexity of determining the number of PHICH groups increases
Solution Approach 1:
The patent changes the parameter used for PHICH group determination based on the subframe type. For UL subframes, it uses a fixed multiple of 1, while for DL subframes, it uses configuration-specific multiples from a predefined table. This parameter adaptation resolves the contradiction by making the system adaptable to different UL-DL configurations while keeping the determination process straightforward through predefined rules.
2Productivity
If different multiples are used for PHICH group determination in UL and DL subframes, then resource allocation can be optimized for each subframe type, but the control logic becomes more complex
Solution Approach 1:
The patent segments the PHICH group determination process into two distinct cases: UL subframes use a fixed multiple of 1, while DL subframes use configuration-specific multiples from a table. This segmentation allows optimized resource allocation for each subframe type while simplifying the control logic through clear, separate rules for each case, resolving the contradiction between productivity and ease of operation.
3Adaptability or versatility
If PHICH resources are allocated based on first UL-DL configuration information, then resource management can be optimized for dynamic TDD configurations, but the determination process becomes more complex
Solution Approach 1:
The patent performs preliminary action by defining a table of multiples corresponding to different UL-DL configurations before the actual PHICH group determination. This pre-prepared table allows the system to adapt to dynamic TDD configurations while simplifying the detection process, as the UE can directly lookup the appropriate multiple based on the configuration index without performing complex calculations in real-time.
Data Source
AI summary
The present invention relates to a wireless communication system. Specifically, the present invention provides a method for receiving control information by a terminal and an apparatus therefor, the method comprising the steps of: receiving an upper layer signal having first UL-DL configuration information for a TDD cell; receiving a lower layer signal having second UL-DL configuration information for the TDD cell; receiving a DL signal in subframe i of the TDD cell according to the second UL-DL configuration information; and detecting the control information on the basis of the number of PHICH groups in the subframe i.