# US 10,575,142 B2 · Hopping master in wireless conference

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- Number: US 10,575,142 B2
- Document ID: US10575142B2
- Status: Granted
- Kind: B2
- Application number: 15/816,788
- Filed: 2017-11-17
- Published: 2018-07-12
- Granted: 2020-02-25
- Earliest claimed: 2012-04-13
- Assignees: Dominant Technologies, LLC
- Applicants: Dominant Technologies, LLC
- Inventors: Ronald H. Fraser
- Web page: https://patentgrep.com/patent/US10575142B2

## CPC

- H04W 4/10: Push-to-Talk [PTT] or Push-On-Call services
- H04L 5/1469: {using time-sharing}
- H04M 1/00: Substation equipment, e.g. for use by subscribers (subscriber services or facilities provided at exchanges H04M3/00; prepayment telephone coin boxes H04M17/00; current supply arrangements H04M19/08)
- H04M 3/565: {relating to time schedule aspects}
- H04W 8/005: {Discovery of network devices, e.g. terminals}
- H04W 56/0015: {one node acting as a reference for the others}
- H04W 72/0446: Resources in time domain, e.g. slots or frames
- H04W 84/20: Leader-follower arrangements
- H04J 3/0641: {Change of the master or reference, e.g. take-over or failure of the master}
- H04W 72/21: in the uplink direction of a wireless link, i.e. towards the network
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04M: TELEPHONIC COMMUNICATION (circuits for controlling other apparatus via a telephone cable and not involving telephone switching apparatus G08)
- H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S)

## Abstract

A first radio has duplex communication with a second radio, without using a base station by using a multiple-access protocol system. The first radio is configured to perform as a slave radio and then switch to be a master radio based on a master flag. A master radio provides timing synchronization and/or assigns transmission slots for radios in the multiple-access protocol system.

## Claims

### Claim 1

A radio configured to switch from being a slave radio to a master radio, the radio comprising:
a receiver configured to receive a first transmission, wherein:
the radio is a first radio;
the first transmission is received from a second radio;
the first transmission uses a time-division multiple access (TDMA) protocol;
the second radio functions as a master radio for the TDMA protocol during the first transmission;
the first radio is a mobile, handheld radio; and
the second radio is a mobile, handheld radio;
a parameter set to indicate the first radio has preference to be a master radio, wherein the parameter is set before the first transmission; and
a transmitter configured to:
transmit a second transmission using the TDMA protocol, wherein:
the second transmission is from the first radio to the second radio;
the second transmission is configured to occur after the first transmission;
the second transmission includes a request to the second radio for the first radio to function as the master radio for the TDMA protocol based on the parameter set to indicate the first radio has preference to be a master radio;
transmit a third transmission using the TDMA protocol, wherein:
the third transmission is configured to be received by the second radio and a third radio;
the third radio is a mobile, handheld radio;
the third transmission is configured to occur after the second transmission;
the first radio is configured to not power off between receiving the first transmission and sending the third transmission;
the first radio functions as the master radio for the TDMA protocol during the third transmission;
the TDMA protocol enables the first radio and the second radio to communicate directly with each other without using a base station while the first radio functions as the master radio;
the TDMA protocol enables the first radio and the third radio to communicate directly with each other without using a base station while the first radio functions as the master radio; and
the TDMA protocol enables the second radio and the third radio to communicate directly with each other without using a base station while the first radio functions as the master radio.

### Claim 2 (depends on 1)

The radio of claim 1, further comprising the second radio and the third radio.

### Claim 3 (depends on 1)

The radio of claim 1, wherein the third transmission comprises audio communication derived from a user of the first radio.

### Claim 4 (depends on 1)

The radio of claim 1, wherein:
the first radio is configured to join a wireless-conferencing group as a slave radio to the second radio by entering a search-for-master routine after powering on and before the first transmission; and
the first radio joins the wireless-conferencing group based on the first radio receiving communication from the second radio during the search-for-master routine.

### Claim 5 (depends on 1)

The radio of claim 1, wherein the first radio is configured to receive a response from the second radio that the first radio is to become the master radio for the TDMA protocol.

### Claim 6 (depends on 1)

The radio of claim 1, wherein transmitting the third transmission is based on the first radio being configured to identify that the second radio stopped transmitting during a known transmission slot of the TDMA protocol.

### Claim 7 (depends on 1)

The radio of claim 1, wherein the first radio is configured to assign a transmission slot of the TDMA protocol to the second radio, after the first transmission and before the third transmission.

### Claim 8

A method for switching a radio from being a slave radio to a master radio in a time-division multiplexed communication system, the method comprising:
receiving, using a first radio, a first transmission from a second radio using a time-division multiple access (TDMA) protocol, wherein:
the second radio functions as a master radio for the TDMA protocol during the first transmission;
the first radio has a parameter set to indicate the first radio has preference to be a master radio;
the parameter is set before the first transmission;
the first radio is a mobile, handheld radio; and
the second radio is a mobile, handheld radio;
determining, using the first radio, that the first radio has the parameter set to indicate that the first radio has preference to be a master radio, wherein determining, using the first radio, that the first radio has the parameter set to indicate the first radio has preference to be the master radio is performed after the first transmission and while the second radio functions as the master radio;
transmitting, using the first radio, a second transmission, wherein:
the second transmission is from the first radio to the second radio and to a third radio;
the third radio is a mobile, handheld radio;
the second transmission occurs after the first transmission; and
the second transmission includes a request to the second radio for the first radio to function as the master radio for the TDMA protocol based on the first radio determining that the first radio has the parameter set to indicate that the first radio has preference to be the master radio; and
transmitting, using the first radio, a third transmission using the TDMA protocol, wherein:
the third transmission occurs after the second transmission;
the first radio does not power off between receiving the first transmission and sending the third transmission;
the first radio functions as the master radio for the TDMA protocol during the third transmission;
the TDMA protocol enables the first radio and the second radio to communicate directly with each other without using a base station while the first radio functions as the master radio;
the TDMA protocol enables the first radio and the third radio to communicate directly with each other without using a base station while the first radio functions as the master radio; and
the TDMA protocol enables the second radio and the third radio to communicate directly with each other without using a base station while the first radio functions as the master radio.

### Claim 9 (depends on 8)

The method of claim 8, further comprising the first radio joining a wireless-conferencing group before receiving the first transmission, wherein the second radio is one of one or more radios that are part of the wireless-conferencing group.

### Claim 10 (depends on 9)

The method of claim 9, wherein the first radio joins the wireless-conferencing group as a slave radio after powering on and entering a search-for-master routine; and the first radio joins the wireless-conferencing group based on the first radio receiving a transmission from the second radio during the search-for-master routine.

### Claim 11 (depends on 8)

The method of claim 8, further comprising determining that the second radio is a new master radio based on the second radio becoming the master radio for the TDMA protocol after a fourth radio stopped being the master radio for the TDMA protocol.

### Claim 12 (depends on 8)

The method of claim 8, further comprising the first radio switching from a listen-only mode to a transmitting mode after the first transmission and before transmitting the second transmission.

### Claim 13 (depends on 8)

The method of claim 8, further comprising the first radio receiving a response from the second radio that the first radio is to become the master radio for the TDMA protocol.

### Claim 14 (depends on 8)

The method of claim 8, transmitting the third transmission based on the second radio not transmitting during a known transmission slot of the TDMA protocol.

### Claim 15 (depends on 8)

The method of claim 8, wherein the first radio and the second radio transmit and receive audio communication to each other without using a base station.

### Claim 16 (depends on 8)

The method of claim 8, further comprising assigning, using the first radio, a transmission slot of the TDMA protocol to the second radio, after the first transmission and before the third transmission.

### Claim 17

A method comprising:
receiving, using a first radio, a first transmission from a second radio, using a time-division multiple access (TDMA) protocol, wherein:
the second radio functions as a master radio for the TDMA protocol during the first transmission;
the first radio has a parameter set to indicate the first radio has preference to be a master radio;
the parameter is set before the first transmission;
the first radio is a mobile, handheld radio; and
the second radio is a mobile, handheld radio;
determining, using the first radio, that the first radio has the parameter set to indicate that the first radio has preference to be a master radio;
transmitting, using the first radio, a second transmission using the TDMA protocol, wherein:
the second transmission is from the first radio to the second radio and to a third radio;
the third radio is a mobile, handheld radio;
the second transmission occurs after the first transmission;
the second transmission includes a request to the second radio for the first radio to function as the master radio for the TDMA protocol;
transmitting, using the first radio, a third transmission using the TDMA protocol, wherein:
the third transmission occurs after the second transmission;
the first radio does not power off between receiving the first transmission and sending the third transmission;
the first radio functions as a slave for the TDMA protocol during the third transmission
the TDMA protocol enables the first radio and the second radio to communicate directly with each other without using a base station while the second radio functions as the master radio;
the TDMA protocol enables the first radio and the third radio to communicate directly with each other without using a base station while the second radio functions as the master radio; and
the TDMA protocol enables the second radio and the third radio to communicate directly with each other without using a base station while the second radio functions as the master radio.

### Claim 18 (depends on 17)

The method of claim 17, further comprising receiving a transmission from the second radio denying that the first radio to function as the master radio for the TDMA protocol.

### Claim 19 (depends on 17)

The method of claim 17, further comprising transmitting the third transmission based on a timeout of the request, wherein the timeout is based on one or more of a number of TDMA frames, a number of search sequences, and/or a lapse of time.

### Claim 20 (depends on 17)

The method of claim 17, wherein:
the request to the second radio for the first radio to function as the master radio for the TDMA protocol is a first request; and
the method further comprises transmitting a second request from the first radio to the second radio for the first radio to function as the master radio for the TDMA protocol.