OFDMA Subscriber Terminal Multi-Cell Concurrent Communication

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Solution Overview

Problem

Legacy IEEE 802.16 wireless networks do not fully exploit OFDMA Fractional Frequency Reuse due to a subscriber device being limited to communicating with only one base station, restricting simultaneous decoding of multiple data streams within a radio frame.

Innovation Solution

A method and apparatus enabling a subscriber device to concurrently communicate with multiple base stations within the same radio frame without strict synchronization, using OFDM/OFDMA sub-channels with distinct sub-carriers and allowing the device to act as a relay for communication between base stations, with control messages conveyed through different sub-channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a subscriber device communicates with only one base station in Legacy IEEE 802.16, then the device can decode data/control streams from that base station, but the full OFDMA Fractional Frequency Reuse potential is not exploited

Engineering Contradiction:

ImproveOFDMA Fractional Frequency Reuse potentialVSAvoidsystem performance

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The frequency channel is segmented into multiple OFDMA sub-channels, each associated with different base stations. The subscriber device can selectively receive and decode data from multiple base stations by processing different sub-channels simultaneously, enabling full exploitation of OFDMA FFR potential while maintaining system performance

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The subscriber device is enhanced to perform multiple functions: it can communicate with a single base station for backward compatibility, or simultaneously communicate with multiple base stations to exploit OFDMA FFR potential, making the system adaptable to different operational modes

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Productivity

If a subscriber device communicates with multiple base stations simultaneously, then system performance and data rates improve, but stringent synchronization at physical OFDM symbol level is required

Engineering Contradiction:

Improvedata ratesVSAvoidsynchronization requirements

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent shifts the synchronization approach from time-domain (physical OFDM symbol level) to frequency-domain resource allocation. By assigning different OFDMA sub-channels to different base stations, the system achieves multi-base station communication without requiring stringent time synchronization, as each sub-channel operates independently in the frequency domain

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Quantity of substance

If FFT processing is carried out for the entire frequency channel, then all sub-carriers are processed, but the subscriber device can decode only one data stream at a time

Engineering Contradiction:

Improvefrequency channel processingVSAvoidstream decoding capability

Core Design Contradiction:

Quantity of substanceVSProductivity

Solution Approach 1:

The frequency channel is divided into multiple OFDMA sub-channels, each carrying independent data streams from different base stations. The subscriber device performs FFT processing on the entire frequency channel but can selectively decode multiple data streams by identifying and processing signals from different base stations on different sub-channels, thereby increasing stream decoding capability

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS9083396B2OFDMA-based operation of a wireless subscriber terminal in a plurality of cells

Publication Date: 2015.07.14 ALVARION LTD

AI summary

A method for carrying out concurrent communications between a subscriber device and two base stations is disclosed. At least one OFDM/OFDMA sub-channel is selected for each of the two base stations which is associated with a communications sector belonging to one of the two base stations and comprises OFDM/OFDMA sub-carriers that are substantially different from sub-carries comprised in the OFDM/OFDMA sub-channel associated with a communications sector belonging to the other base station; establishing a communication path between the subscriber device and each of the two base stations along the respective sub-channel selected; receiving/transmitting control messages exchanged between the subscriber device and the two base stations, wherein at least one control message is exchanged between the subscriber device and one of the two base stations concurrently with at least one control message exchanged between the subscriber device and the other base station, and wherein the control messages are exchanged along different sub-channels comprised in the communication paths.