Control Channel Beamforming via Orthogonal Preambles

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Solution Overview

Problem

Current wireless communication systems using beamforming for traffic data struggle to efficiently manage control information, leading to high overhead and reduced benefits due to the need for broadcasting control channels broadly, which interferes with data transmission and requires additional processing and spectrum usage.

Innovation Solution

A method and system that broadcast multiple orthogonal preambles with different beamforming patterns to allow subscriber stations to independently detect and receive control information, reducing the need for additional processing and spectrum usage, and enabling beamforming of control channels without affecting existing receiving mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If control information is broadcasted omnidirectionally to cover the whole cell, then all subscriber stations can receive the control information, but the beam width becomes wide and interferes with nearby traffic channels

Engineering Contradiction:

Improvecontrol channel coverageVSAvoidinterference with traffic channels

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The control channel is segmented into multiple directional beams, each covering a specific sector of the cell. Instead of one omnidirectional broadcast, the system transmits control information through multiple directional beam formations, allowing selective coverage reduction of interference while maintaining comprehensive coverage through the combination of all beams.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different spatial regions receive control information through different beam configurations. Each subscriber station receives control information optimized for its specific location through directional beamforming, rather than a uniform omnidirectional signal. This allows the system to tailor the beam width and direction to match the local coverage requirements.

Inventive Principle:

Principle #3Local quality

2Productivity

If narrow beamforming is used for traffic data, then spectral efficiency is improved, but control channel performance suffers due to the need for broad broadcasting

Engineering Contradiction:

Improvespectral efficiencyVSAvoidcontrol channel performance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system dynamically adjusts the beamforming configuration based on whether the transmission is for control information or traffic data. For traffic data, narrow beams provide high spectral efficiency. For control information, the system dynamically creates broader beams or multiple directional beams to ensure all subscriber stations can receive the control channel, thus adapting the beam width to the specific transmission requirements.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The beamforming system serves multiple functions: it provides narrow beams for high-efficiency traffic data transmission and simultaneously creates broader or multiple directional beams for control information distribution. This multi-functionality allows the same physical layer infrastructure to support both high spectral efficiency and reliable control channel delivery.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If Diversity Map Scan mode is used to improve control channel efficiency, then link budget is balanced, but overhead increases and beamforming benefits are reduced

Engineering Contradiction:

Improvelink budget balanceVSAvoidoverhead

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the control channel transmission with the beamforming training process. Instead of separate Diversity Map Scan procedures that require additional overhead messages and signaling, the control information is embedded within the beamforming training sequences. This combination allows the system to achieve link budget balance through beamforming while avoiding the overhead associated with separate control channel scanning procedures.

Inventive Principle:

Principle #5Merging (Combining)

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 control channel overhead, conserves frequency spectrum, and enhances system capacity by allowing beamforming of control information without additional processing for subscriber stations, achieving a link budget gain and improving the ranging process.

Implementation Method 1

applying beamforming to control information of the telecommunication systems through an antenna array

Methodology Applied

Scientific EffectBeamforming:

Implementation Method 2

transmitting multiple narrowband signals (called AAS-DLFPs) one after the other in the time domain

Methodology Applied

Scientific EffectAntenna array radiation:

Data Source

PatentUS8040831B2Method and system for control channel beamforming

Publication Date: 2011.10.18 CISCO TECHNOLOGY INC

AI summary

A system and method for managing control information in a wireless communications system. The method comprises broadcasting a predetermined number of preambles through beamforming from a base station, detecting, by a subscriber station, a predetermined frame associated with one selected preamble that has the highest power level, and identifying one or more subcarriers for carrying control information through the selected preamble.