# US 2019/0380102 A1 · Node unit capable of measuring and compensating transmission delay and distributed antenna system including the same

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- Number: US 2019/0380102 A1
- Document ID: US20190380102A1
- Status: Published application
- Kind: A1
- Application number: 16/548,929
- Filed: 2019-08-23
- Published: 2019-12-12
- Earliest claimed: 2014-12-30
- Assignees: SOLiD, INC.
- Applicants: SOLiD, INC.
- Inventors: Doyoon Kim; Hyoungho Kim
- Web page: https://patentgrep.com/patent/US20190380102A1

## CPC

- H04W 56/005: {compensating for timing error by adjustment in the receiver}
- H04B 17/10: of transmitters
- H04B 17/104: {of other parameters, e.g. DC offset, delay or propagation times}
- H04B 17/14: of the whole transmission and reception path, e.g. self-test loop-back
- H04L 7/0041: {Delay of data signal}
- H04W 56/007: {Open loop measurement}
- H04W 88/085: {Access point devices with remote components}
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- H04B: TRANSMISSION
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

Provided is a node unit which is branch-connected to another communication node via a transport medium, the node unit comprising: a delay measurement unit which transmits a test signal for measuring a delay to an adjacent node unit of the branch-connected upper stage via the transport medium and detects a loopback signal to which the test signal is looped back via the adjacent node unit of the upper stage, thereby measuring an upper stage transmission delay between the adjacent node unit of the upper stage and the node unit; a delay summation unit which, when an adjacent node unit of the branch-connected lower stage exists, receives a lower stage transmission delay transmitted from the adjacent node unit of the lower stage, and calculates a summed transmission delay by summing the upper stage transmission delay and the lower stage transmission delay; and a control unit which transmits the summed transmission delay to the adjacent node unit of the upper stage.

## Claims

### Claim 1

A node unit of a digital radio frequency (RF) transport system, the node unit comprising at least one processor and at least one memory to implement:
a delay measurer configured to measure a first delay between the node unit and a first adjacent node unit;
a delay summer configured to generate a summed delay by summing the first delay and a second delay between the node unit and a second adjacent node unit, wherein the second delay is received from a second adjacent node unit;
a controller configured to calculate a compensation value based on the summed delay and delay deviation information; and
a delay compensator configured to perform a delay compensation operation for equalizing a delay of entire of the digital RF transport system based on the compensation value,
wherein the delay deviation information corresponds to a difference between a maximum delay in the digital RF transport system and the summed delay.

### Claim 2 (depends on 1)

The node unit of claim 1, wherein the delay deviation information is received from the first adjacent node unit or the second adjacent node unit.

### Claim 3 (depends on 2)

The node unit of claim 2, wherein the delay deviation information is received via a control & management (C&M) channel.

### Claim 4 (depends on 1)

The node unit of claim 1, wherein the maximum delay of the digital RF transport system is a delay having a maximum value among the summed delay in a branch including the node unit and other summed delays of other branches.

### Claim 5 (depends on 1)

The node unit of claim 1, wherein the delay measurer is configured to transmit a test signal to the first adjacent node unit and measure the first delay based on the test signal looped back by the first adjacent node unit.

### Claim 6 (depends on 1)

The node unit of claim 1, wherein the controller is configured to calculate the compensation value by summing the summed delay and the delay deviation information.

### Claim 7 (depends on 1)

The node unit of claim 1, wherein the controller is configured to transmit the summed delay to the first adjacent node unit or the second adjacent node unit.

### Claim 8 (depends on 1)

The node unit of claim 1, wherein the delay compensator is configured to perform the delay compensation operation with respect to a plurality of the digitized RF signal transmitted to the first adjacent node unit or the second adjacent node unit.

### Claim 9 (depends on 8)

The node unit of claim 8, wherein the delay compensator is configured to selectively perform the delay compensation operation with respect to a portion of the plurality of the digitized RF signal.

### Claim 10 (depends on 1)

The node unit of claim 1, wherein the first adjacent node unit, the node unit and the second adjacent node unit are connected in a cascade manner.

### Claim 11 (depends on 1)

The node unit of claim 1, wherein, when a third adjacent node unit connected to the second adjacent node unit exists, the second delay includes a third delay between the third adjacent node unit and the second adjacent node unit.