Wireless Coexistence via Superframe Synchronization

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Solution Overview

Problem

Wireless technologies such as IEEE 802.15.4 and DECT, operating in the same frequency band, often interfere with each other due to sporadic and irregular transmissions, as DECT struggles to detect IEEE 802.15.4 activity in Contention Access Periods, leading to mutual interference.

Innovation Solution

A method that initializes the IEEE 802.15.4 network with a superframe period aligned with DECT's, allowing communication in distinct periods, dynamically allocates time slots, and uses a network configuration component to primarily utilize dedicated bandwidth, minimizing shared bandwidth usage, and optionally transmits dummy data to avoid interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If IEEE 802.15.4 and DECT operate in the same frequency band with independent time slot allocation, then each technology maintains its own communication efficiency, but mutual interference occurs due to overlapping transmissions

Engineering Contradiction:

Improvecommunication efficiencyVSAvoidinterference

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent merges the time slot allocation mechanisms of IEEE 802.15.4 and DECT by synchronizing their superframe periods and aligning Contention Free Periods with DECT time slots. This coordination allows both technologies to share the frequency band without mutual interference, as transmissions from different technologies occur in synchronized, non-conflicting time windows.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent implements dynamic time slot allocation where the IEEE 802.15.4 coordinator can flexibly adjust the superframe period and Contention Free Period configuration based on detected DECT activity. This dynamic adaptation enables the system to optimize coexistence by adjusting transmission patterns in response to changing channel conditions and DECT usage patterns.

Inventive Principle:

Principle #15Dynamics

2Measurement precision

If DECT uses periodic scanning to detect busy channels, then it can avoid some interference, but sporadic IEEE 802.15.4 transmissions in Contention Access Period remain undetected

Engineering Contradiction:

Improvechannel detection accuracyVSAvoiddetection of sporadic transmissions

Core Design Contradiction:

Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent extracts IEEE 802.15.4 transmissions from the Contention Access Period and relocates them to the Contention Free Period, which is synchronized with DECT time slots. By removing the problematic sporadic transmissions from the CAP and confining them to the CFP, the system eliminates the source of undetected interference while maintaining overall communication functionality.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies preliminary action by having the IEEE 802.15.4 coordinator proactively configure the superframe structure to align with DECT timing before interference occurs. The coordinator pre-establishes the Contention Free Period boundaries and restricts data transmissions to these predetermined windows, preventing interference issues rather than reacting to them after detection.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If IEEE 802.15.4 uses Contention Access Period for flexible data transmission, then it achieves high adaptability, but it creates irregular transmission patterns that interfere with DECT

Engineering Contradiction:

Improvetransmission flexibilityVSAvoidinterference to DECT

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by creating distinct transmission zones within the IEEE 802.15.4 superframe structure. The Contention Access Period is designated for control traffic and beacon transmissions (localized, predictable patterns), while the Contention Free Period is designated for data transmissions (flexible, adaptive patterns). This spatial-temporal separation allows each zone to have optimized characteristics without interfering with DECT operations.

Inventive Principle:

Principle #3Local quality

Data Source

PatentEP1913737B1A time-based coexistence method for wireless communication

Publication Date: 2012.09.12 KONINKLIJKE PHILIPS NV

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AI summary

A method for facilitating coexistence of wireless technologies competing for the same bandwidth includes, with a first component (14) residing in a first wireless network (20), initializing the first wireless network (20) with a superframe period (38) based on a superframe period (28) of a second wireless network (10) and communicating information over the first wireless network (20) within the Contention Free Period period (46) of the superframe period (38) of the first wireless network (20), and, with a second component (4) residing in the second wireless network (10), communicating information over the second wireless network (10) within the Contention Access Period (44) of the superframe period (38), the Contention Free Period (46) and the Contention Access Period (44) being distinct regions of the superframe period (38) of the first wireless network (20).