Base Station Initial Connection Timing and Directivity Control

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Solution Overview

Problem

Establishing an initial connection in LTE mobile communication systems while switching directivity results in longer times compared to non-directional transmission, due to the lack of precise directionality in search signal transmission.

Innovation Solution

A base station and terminal apparatus configuration that includes timing control for search and broadcast signals, directional transmission and reception of these signals with reception-timing information, and directivity control to align directivity patterns with the transmission direction, allowing for efficient initial connection establishment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the base station transmits search signals in all directions sequentially while switching directivity, then the cell coverage area is expanded, but the time required for initial connection establishment increases

Engineering Contradiction:

Improvecell coverage areaVSAvoidinitial connection establishment time

Core Design Contradiction:

Area of stationary objectVSLoss of time

Solution Approach 1:

The base station performs preliminary directivity control during the search signal transmission phase, pre-aligning the antenna array's directivity pattern with the terminal apparatus's location before the RACH signal transmission phase begins. This preliminary alignment eliminates the need for time-consuming directivity switching during the critical connection establishment phase, thereby reducing overall connection time while maintaining expanded cell coverage

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts the directivity control timing and pattern based on the connection phase. During the search signal phase, directivity is switched across multiple directions to expand coverage. During the RACH phase, directivity is fixed on the detected terminal direction. This dynamic adaptation resolves the contradiction between coverage expansion and connection speed

Inventive Principle:

Principle #15Dynamics

2Quantity of substance

If the base station uses millimeter wave band for communication, then the bandwidth is increased to 1 GHz or greater, but the propagation loss increases significantly and reachable distance is reduced

Engineering Contradiction:

ImprovebandwidthVSAvoidpropagation loss

Core Design Contradiction:

Quantity of substanceVSLoss of energy

Solution Approach 1:

The base station concentrates transmitted energy into specific directional beams using antenna array-based directivity control, rather than distributing energy uniformly in all directions. This creates localized high-intensity transmission paths toward terminal apparatuses, compensating for millimeter wave propagation losses and extending reachable distance while maintaining the high bandwidth capability

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system transitions from omnidirectional transmission (360-degree coverage) to directional beam transmission, adding the spatial dimension of directivity control. This allows the system to overcome propagation loss by focusing energy in specific three-dimensional directions, effectively extending the communication range of millimeter wave bands

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Productivity

If the base station performs directivity control using antenna elements, then the cell area is expanded and communication speed is enhanced, but the time for initial connection establishment increases due to directivity switching

Engineering Contradiction:

Improvecommunication speedVSAvoidinitial connection establishment time

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The directivity control is maintained continuously and consistently during the RACH signal transmission phase, rather than switching directions. This continuous alignment ensures that the high-speed communication capability is immediately available once connection is established, while avoiding interruptions caused by directivity switching during the connection process

Inventive Principle:

Principle #20Continuity of useful action

Data Source

PatentUS9980206B2Base station, terminal apparatus, and initial connection method

Publication Date: 2018.05.22 PANASONIC HOLDINGS CORP

AI summary

In order to shorten the time in which an initial connection is established when switching directivity and then performing the initial connection, a frame timing control unit sets, until detection of an RACH signal, a transmission timing of a transmission frame for transmitting a search signal and a broadcast signal and also sets a reception-start timing for starting the reception of the corresponding RACH signal. A search/broadcast signal generation unit generates the broadcast signal and the search signal including reception-timing information. A beam directivity control unit sets, for a predetermined time starting from the reception-start timing, a directivity pattern such that the directivity is in the same direction as the directivity pattern for the corresponding transmission-timing information, whereby the beam directivity control unit controls a beam directivity operation unit.