PHICH Resource Mapping for FD-MIMO Collision Reduction
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Solution Overview
Problem
In cellular communication networks, especially in FD MIMO systems, the increased number of antennas leads to a higher likelihood of resource collisions, particularly with Physical Hybrid-ARQ Indicator Channel (PHICH) resource collisions, which affect the efficiency of signal reception and transmission.
Innovation Solution
The proposed solution involves alternative PHICH resource mapping techniques, including the addition of a PHICH resource offset and the use of multiplicative factors in the resource mapping equations, to reduce or eliminate PHICH resource collisions. This is achieved by adjusting the group and sequence indices based on specific parameters such as Transport Block (TB) indices, DMRS cyclic shifts, and spreading factor sizes, and optionally incorporating PHICH time offsets and implicit ACK/NACK feedback mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large number of antenna elements are used in MIMO antenna arrays, then diversity gain and ability to receive signals from multiple mobile devices are improved, but resource collisions become more frequent
Solution Approach 1:
The patent segments the PHICH resource space by introducing separate group offset and sequence offset parameters. This divides the originally collision-prone resource space into distinct segments for different UEs, allowing multiple UEs to share the same physical resources without collision. The segmentation of resource allocation parameters directly addresses the problem of resource collisions in FD-MIMO systems with large antenna arrays.
Solution Approach 2:
The patent applies local quality by making PHICH resource allocation UE-specific through individual offset parameters. Each UE receives customized group and sequence offsets tailored to its specific uplink allocation, rather than using a uniform resource allocation scheme. This localized resource allocation prevents collisions while maintaining the benefits of large antenna arrays.
2Device complexity
If PHICH resource mapping uses standard equations without offsets, then resource allocation is simple, but PHICH resource collisions occur frequently
Solution Approach 1:
The patent modifies the PHICH resource mapping equations by introducing two new parameters: group offset and sequence offset. These parameter changes transform the standard mapping equations into UE-specific mapping equations. The modified equations maintain the original structure for backward compatibility while adding offset terms that eliminate collisions, achieving a balance between complexity and reliability.
3Productivity
If multiple UEs share the same uplink resources, then resource utilization efficiency is improved, but PHICH resource collisions increase
Solution Approach 1:
The patent introduces group offset and sequence offset as intermediary parameters that mediate between multiple UEs sharing the same uplink resources. These offsets act as virtual separators that allow simultaneous resource sharing without actual collision. The intermediaries enable efficient resource utilization while preventing the harmful effects of collisions.
Data Source
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AI summary
Disclosed herein are apparatuses, systems, and methods using or implementing full-dimension multi-input multi-output (FD-MIMO) and providing collision reduction by transmitting data to an evolved Node-B (eNB) on an uplink (UL) resource; and receiving an acknowledgement (ACK) or negative acknowledgment (NACK) on a physical HARQ-ACK indicator channel (PHICH), responsive to transmitting the data on the UL resource. The PHICH may be mapped to a least physical resource block (PRB) that is offset by a PHICH offset. The PHICH offset may include a group offset and a sequence offset relative to a transport block (TB) index and first PRB index of a corresponding uplink shared channel. Other embodiments are described.