Late Join Frame for Spread Spectrum Call Entry
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Solution Overview
Problem
Existing communication systems, particularly Push-to-talk (PTT) radios, face challenges in allowing late joining of ongoing calls due to the reliance on receiving initial call setup information, which can result in missed data and compromised call quality if a target device misses some or all of the call setup information.
Innovation Solution
The introduction of a 'late join frame' that replaces a traffic frame with a late join slot containing sufficient preamble and sync subframes, enabling a target device to join an ongoing call without significantly affecting call quality, even if one or more traffic slots are not received.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a target device misses call setup information during the connection establishment phase, then it cannot join the ongoing call using traditional methods, but the patent introduces late join frames that allow the target to join anyway by providing essential call information in periodic traffic frames
Solution Approach 1:
The patent embeds call setup information (preamble and sync subframes) periodically within traffic frames during the traffic phase, allowing targets to acquire necessary call information at any point during the call rather than requiring presence during the initial connection establishment phase
Solution Approach 2:
The late join frame acts as an intermediary mechanism that carries essential call information (preamble, sync subframes, and call parameters) within the existing traffic frame structure, enabling targets to join calls they would otherwise miss
2Adaptability or versatility
If the system transmits late join frames periodically during the traffic phase, then targets can join ongoing calls, but this may affect call quality if traffic slots are not received
Solution Approach 1:
The patent designates specific portions of traffic frames (late join slots) to carry call information for joining targets, while other portions continue to carry normal traffic data, allowing the system to serve both functions simultaneously with differentiated quality requirements
Solution Approach 2:
The system transmits redundant call information (preamble and sync subframes) periodically within traffic frames, providing more opportunities for targets to acquire necessary information than the minimum single transmission would provide
3Productivity
If frequency hopping is used to meet FCC spectrum distribution requirements, then spectrum utilization is uniform, but targets may miss call setup information on specific frequencies
Solution Approach 1:
The patent transmits late join frames with call information periodically at predetermined intervals during the traffic phase, ensuring that targets have multiple opportunities to acquire necessary information regardless of when they join the call
Data Source
AI summary
Methods of enabling late entry into an on-going spread spectrum call are described. A late join frame replaces, and has the same size as, a traffic frame. A late join slot in the late join frame contains sufficient information in preamble and sync subframes to permit a target to join the call. The traffic slots in the late join frame replicate data such that call quality of the call is substantially unaffected if one of the remaining traffic frames is not received. The preamble and sync subframes frequencies may be the same as, or different from, preamble and sync frames frequencies during a call establishment phase of the call. If different, the preamble and sync subframes frequencies are selected from one or more frequencies. Use of the preamble and sync subframes frequencies is compensated for when selecting the traffic slot frequencies to obtain uniform utilization of the spectrum.