PoC Access Probe Collision Reduction via Transceiver Segmentation

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Solution Overview

Problem

In cellular networks, the initiation of Push-to-talk over Cellular (PoC) sessions is hindered by collisions between access probes from multiple wireless devices, leading to delayed session establishment and poor user experience due to the need for repeated attempts and random timing to avoid collisions.

Innovation Solution

Implementing a method where multiple transceivers can receive and decode access probes using common or primary/secondary access codes, allowing any transceiver to listen for and decode access probes regardless of service association, and determining which transceiver to take response actions based on signal quality and service association.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple wireless devices transmit access probes to the same transceiver simultaneously, then the network can handle more communication requests, but collisions occur between access probes causing failed reception and decoding

Engineering Contradiction:
Improvenumber of access probes handledVSAvoidsuccessful reception and decoding of access probe
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent segments the access probe reception function across multiple transceivers. Instead of one transceiver handling all access probes, multiple transceivers are assigned to monitor and decode access probes on different channels or time slots, reducing collisions and improving successful reception rates

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements preliminary action by having transceivers pre-configure their monitoring capabilities and access probe handling procedures before collisions occur. Transceivers are pre-assigned specific channels or time slots to monitor, and the system pre-establishes protocols for handling multiple simultaneous access probes, enabling faster and more reliable processing

Inventive Principle:
Principle #10Preliminary action

2Reliability

If access probes are transmitted at random time intervals to reduce collisions, then collision likelihood decreases, but PoC session establishment time increases due to repeated failed attempts

Engineering Contradiction:
Improvereduction of access probe collisionsVSAvoidPoC session establishment time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements periodic action by establishing regular time slots for access probe transmissions. Instead of random intervals, wireless devices transmit access probes at predetermined periodic intervals, and transceivers are configured to monitor these specific time slots, ensuring systematic coverage and reducing missed detections while maintaining collision avoidance

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent applies universality by making multiple transceivers capable of handling access probes from multiple wireless devices simultaneously. Each transceiver can monitor multiple channels and decode access probes from different devices, creating a universal access probe reception system that reduces both collisions and establishment time through parallel processing

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Device complexity

If a single transceiver is responsible for decoding access probes, then the system is simpler to manage, but the probability of successful decoding decreases when collisions occur

Engineering Contradiction:
Improvetransceiver management complexityVSAvoidaccess probe decoding success rate
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent segments the decoding responsibility across multiple transceivers, with each transceiver assigned to monitor specific channels or time slots. This segmentation reduces the load on individual transceivers and increases the overall system's decoding success rate by providing multiple opportunities for successful reception

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a mediator component that coordinates between multiple transceivers and wireless devices. This mediator manages the assignment of channels and time slots, handles collision resolution, and ensures that access probes are properly routed to the appropriate transceivers for decoding, maintaining system simplicity while improving reliability

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach reduces collisions and accelerates PoC session establishment by ensuring access probes are received and decoded, even if the primary transceiver fails, thereby improving user experience by minimizing wait times for communication initiation.

Implementation Method 1

The access probe transmitted by the wireless device in a CDMA based wireless network is spread by a pseudo noise (PN) code associated with the transceiver from which the wireless device monitors paging channel. The transceiver distinguishes the access probe from other signals based on the PN code that the access probe signal uses.

Methodology Applied
Scientific EffectPseudo noise code spreading:

Data Source

PatentEP1931162B1Initiating communication in a push-to-talk over cellular (PoC) communication network
Publication Date: 2009.02.18 BLACKBERRY LTD
  • EP1931162B1 patent drawingFigure 1
  • EP1931162B1 patent drawingFigure 2
  • EP1931162B1 patent drawingFigure 3

AI summary

Systems and methods are provided for a cellular network to receive and decode access probes. A wireless device transmits an access probe spread with a PN code to a cellular network. The transceiver to which the wireless device is associated with can receive and decode the access probe. Additionally, other transceivers can receive and decode the access probe. In some implementations, each transceiver listens for access probes spread with their respective transceiver-specific PN code or other PN codes associated with neighbouring transceivers. In other implementations, each transceiver listens for access probes spread with a common access code. There may be more than one common access code in which each transceiver listens for access probes spread with any one of the common access codes.