Quasisynchronous Code Sets for Reservation Requests
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Solution Overview
Problem
Systems utilizing code-division multiplexing for request segments in contention-free protocols require precise time synchronization between nodes, increasing complexity and cost, and there is a need for improved methods to reserve shared communication media efficiently.
Innovation Solution
The use of quasisynchronous code sets, such as generalized orthogonal or quasi-orthogonal codes, with a low correlation window, allows for effective request detection and assignment of transmission opportunities without strict time synchronization, enabling improved performance in noisy environments and relaxed synchronization requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If code-division multiplexing is used for request segments in contention-free protocols, then request detection performance is improved, but time synchronization complexity increases
Solution Approach 1:
The patent changes the code set parameters from strictly orthogonal codes requiring precise synchronization to quasisynchronous codes with bounded cross-correlation. This parameter change in the code selection allows the system to maintain good request detection performance while tolerating timing offsets up to a certain bound, thereby reducing synchronization complexity without sacrificing measurement precision
2Measurement precision
If precise time synchronization is implemented between nodes, then request detection accuracy is improved, but system cost increases
Solution Approach 1:
The patent modifies the code set parameters to use quasisynchronous codes where cross-correlation is bounded rather than strictly zero. This parameter change enables the system to achieve sufficient request detection accuracy without implementing expensive precise synchronization hardware, thereby reducing system cost while maintaining adequate measurement precision
3Productivity
If strict time synchronization requirements are enforced, then transmission efficiency is improved, but device complexity increases
Solution Approach 1:
The patent changes the synchronization parameter requirements from strict (zero tolerance) to quasisynchronous (bounded tolerance). This allows the system to maintain high transmission efficiency by preventing excessive collisions while avoiding the complexity of precise synchronization mechanisms, achieving a balance between productivity and device complexity
Data Source
AI summary
Methods and apparatuses are presented for communicating using a shared communication medium. A request is sent in a request signal space where the request represents a code sequence that is a member of a set of code sequences. Each member is characterized by an autocorrelation function that has a peak centered at zero time offset. Each member is further characterized by a cross correlation function. The cross correlation function has a low correlation window having a width and surrounding a zero time offset. An assignment is received that assigns the request to a transmission opportunity in a scheduled transmission signal space. The assignment is made in response to detecting the code sequence from receiving multiple requests having relative timing offsets less than the width of the low correlation window. A data transmission is sent using the assigned transmission opportunity in the scheduled transmission signal space.