Pilot Time Slot Hopping for MIMO Interference Mitigation
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Solution Overview
Problem
In massive MIMO systems with a time division duplex (TDD) frame structure, achieving orthogonality of pilot time slots for multiple user equipment (UEs) is challenging due to limited time slot space, leading to potential interference and channel state information inaccuracies, especially in densely populated areas where time slots may need to be reused.
Innovation Solution
Implementing a pilot time slot hopping method that allocates non-overlapping header time slots to UEs using predetermined schemes such as pseudo-random, cyclic, or orthogonal patterns, allowing for dynamic re-allocation to mitigate interference-based contamination, and incorporating methods like frequency hopping and synchronization with neighbor cells to optimize resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If time slots are reused for multiple UEs in densely populated areas, then the quantity of UEs served is improved, but interference and channel state information accuracy deteriorate
Solution Approach 1:
The patent implements dynamic time slot allocation where the header time slot assignment to UEs changes over time frames. Instead of static assignment, the system dynamically selects different header time slots for pilot transmission in different time frames, allowing the same time slot to be reused for different UEs at different times while maintaining orthogonality within each frame.
Solution Approach 2:
The patent introduces a time dimension to the header time slot allocation by implementing hopping patterns across multiple time frames. UEs hop through different header time slots (e.g., HO1, HO2, HO3, HO4) in a sequential manner across time frames, transforming the problem from spatial resource allocation to temporal resource allocation.
2Object-affected harmful factors
If pilot time slots are allocated orthogonally for multiple UEs, then interference is reduced, but the limited time slot space restricts the number of UEs that can be served
Solution Approach 1:
The patent implements periodic hopping patterns where UEs cycle through different header time slots in a predetermined sequence. Each UE follows a periodic pattern (e.g., UE1: HO1→HO2→HO3→HO4→HO1, UE2: HO2→HO3→HO4→HO1→HO2) that repeats across time frames, ensuring orthogonal allocation within each period while enabling multiple UEs to share the limited header time slot resources.
3Adaptability or versatility
If time division duplex TDD configuration is used, then uplink and downlink communications are enabled, but interference occurs when neighboring cells have conflicting uplink/downlink schedules
Solution Approach 1:
The patent applies preliminary action by pre-coordinating TDD configurations among neighboring base stations before interference occurs. The network controller exchanges TDD configuration information with neighbor cells and proactively adjusts the header time slot allocations to avoid conflicts, rather than reacting to interference after it happens.
Data Source
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AI summary
Embodiments are directed to systems, methods and computer program products for pilot time slot hopping to mitigate interference-based pilot time slot contamination. Embodiments include generating a multiple input multiple output (MIMO) system message frame structure comprising a header comprising a plurality of header time slots, an uplink (UL) time slot (optional), and a downlink (DL) time slot. Generating includes determining, based on a predetermined scheme, allocation of at least one of the plurality of header time slots to at least one user device within a predetermined area.