Cyclic Shift Offset Randomization for Wireless Interference Mitigation
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Solution Overview
Problem
Conventional wireless communication systems face limitations in allocating sequence resources effectively, particularly in MIMO systems, due to lack of feedback on channel information, leading to interference issues between mobile devices in neighboring cells.
Innovation Solution
A method and apparatus that utilize a cyclic shift offset to randomly assign sequence resources to mobile devices, employing a generator to produce and an assigner to implement this offset, thereby mitigating interference by coordinating or uncoordinating the cyclic shift based on interference detection and location metadata.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sequence resource allocation methods are used without randomization, then the allocation process is simple and deterministic, but interference occurs between mobile devices in neighboring cells due to lack of channel information feedback
Solution Approach 1:
The patent applies preliminary action by pre-generating multiple candidate sequence resources and their corresponding cyclic shift offsets before actual communication occurs. The base station prepares a pool of orthogonal sequences and pre-calculates their cyclic shifts, so that when randomization is needed, the system can quickly select from pre-prepared options rather than computing everything in real-time. This resolves the contradiction by making the randomization process feasible without excessive computational complexity during critical transmission moments.
Solution Approach 2:
The patent implements feedback mechanisms where mobile devices report channel quality indicators and interference levels back to the base station. This feedback enables the base station to adaptively adjust the randomization parameters and select appropriate cyclic shift offsets based on actual channel conditions. By incorporating feedback, the system achieves reliable interference mitigation through informed randomization while keeping complexity manageable through adaptive rather than exhaustive processing.
2Productivity
If cyclic shift offset randomization is implemented to mitigate interference, then spectral efficiency and reliability improve, but the system requires additional processing modules for generating and managing cyclic shifts
Solution Approach 1:
The patent applies universality by designing the cyclic shift generation mechanism to serve multiple functions simultaneously. The same base station processor that handles scheduling and resource allocation also generates cyclic shift offsets and manages sequence randomization. The mobile device's processor performs both channel decoding and local generation of expected cyclic shifts for correlation detection. This multi-functionality approach achieves high spectral efficiency through effective interference mitigation while avoiding the need for separate dedicated processing modules, thus controlling complexity.
Solution Approach 2:
The patent implements self-service by enabling mobile devices to autonomously generate their own cyclic shift offsets using the same algorithms and parameters provided by the base station. Each mobile device independently computes its cyclic shifts based on its assigned orthogonal sequence and the provided randomization seeds, without requiring the base station to explicitly signal each shift value. This self-service capability achieves reliable interference mitigation through consistent randomization while significantly reducing processing complexity and signaling overhead.
3Reliability
If sequence resources are randomly assigned using cyclic shift offsets, then unique resources are ensured for each mobile device, but the system requires coordinated or uncoordinated approaches based on interference detection
Solution Approach 1:
The patent applies dynamics by making the resource allocation management approach adaptive rather than static. The system dynamically switches between coordinated and uncoordinated cyclic shift strategies based on detected interference conditions. When interference is detected between neighboring cells, the system transitions to coordinated mode where base stations exchange information and align their randomization parameters. When interference is absent, the system operates in uncoordinated mode for simpler independent operation. This dynamic adaptation ensures sequence resource uniqueness and reliable interference mitigation while simplifying operation by automatically selecting the appropriate management mode without requiring constant manual configuration.
Data Source
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AI summary
A method for allocating a sequence resource through randomization is described, the method comprising: producing (918) a cyclic shift offset for use in random assignment of the sequence resource to a mobile device, assigning a sequence resource randomly through implementation of the produced cyclic shift offset, characterized in that the method further comprises: determining a distance between base stations, mobile devices or mobile devices and base stations, inferring (904) if the determined distance is such that interference is expected, determining (908) if the cyclic shift offset should be coordinated among nearby base stations or uncoordinated based upon a result of the inference, as well as corresponding apparatus.