Inbound acknowledgement stack

• US 4,646,082 A
• Filed: 09/14/1984
• Issued: 02/24/1987
• Est. Priority Date: 09/14/1984
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Stepien, Michael A., Glidewell, Keith J., Engel, James R.
• Primary Examiner(s): Caldwell, Sr., John W.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US06/651,194
• Time in Patent Office: 893 Days
• Field of Search: 340/825.54, 340/311.1, 340/313, 340/825.44, 340/502, 340/504, 340/505, 179/2 EC, 179/18 BF, 455/56, 370/94, 370/94 V
• US Class Current: 340/10.2
• CPC Class Codes: H04W 74/0808 using carrier sensing, e.g. carrier sense multiple access [CSMA]

Abstract

In a data message communication system, certain messages require a return acknowledgement signal. The present invention contemplates a method and means which are activated whenever an outbound message is received. Each portable unit which receives a message then monitors the outbound communication channel to determine if the inhibit signal is currently active. If the inhibit is not currently active, the particular unit will transmit its acknowledgement message immediately. If the inhibit signal is active, each portable unit will maintain a count of the number of outbound messages, addressed to other units requiring an acknowledgement, since that particular portable received its message. At the termination of the inhibit signal, each portable unit will pause for a period equivalent to the product of the acknowledgement message time slot multiplied by count of messages accumulated since the receipt of the particular portable units message. Each portable unit will then transmit an acknowledgement signal at the termination of its unique pause period.

Claims

1. A method for sequencing acknowledgement messages of a predetermined duration, transmitted from portable or mobile units to a base station in an RF communication system wherein said base station provides inbound and outbound communications channels having data streams wherein an imbedded inhibit signal becomes active in the outbound data stream in the presence of activity on the inbound communications channel, said method comprising the steps of:

(a) receiving an outbound message addressed to a particular mobile unit, said outbound message requiring an acknowledgement of a predetermined duration;

(b) sensing the outbound RF communication channel to determine whether a transmit inhibit is currently active;

(c) transmitting said acknowledgement if said inhibit is not in effect;

(d) observing and counting the number of outbound messages requiring an acknowledgement subsequent to receiving said outbound message;

(e) pausing for a period equivalent to the product of the acknowledge message duration and the number of observed and counted outbound messages subsequent to the receipt of said outbound message addressed to a particular mobile unit wherein said pause period begins at the termination of the imbedded inhibit signal; and

(f) transmitting a particular unit'"'"'s acknowledgement signal at the termination of the pause period.

2. A method for controlling message traffic on a data communications system having a number of remote units and at least one fixed unit, wherein messages are communicated on inbound and outbound message channels, between said fixed and said portable units, and outbound messages may be transmitted in a serial packet from said fixed unit to said portable units on said outbound message channel, said method including the steps of:

(a) receiving a coded message on said outbound message channel, said coded message addressed to a particular remote unit wherein said coded messages require an acknowledgement message of a predetermined time period;

(b) sensing said outbound message channel for further communication activity;

(c) monitoring the outbound message channel if activity is detected on the outbound message channel;

(d) detecting and counting the number of outbound messages subsequent to the end of said received message;

(e) pausing for a period, said period equal to the product of the time period of a single acknowledgement message times the counted number of outbound messages subsequent to said received message; and

(f) transmitting an acknowledgement message at the expiration of said pause period.

3. The method of claim 2 wherein an imbedded inhibit signal becomes active in the outbound message channel in the presence of activity on the inbound message channel.

4. The method of claim 2 further including the step of transmitting an acknowledgement message immediately if no activity is detected on the outbound message channel.

5. The method of claim 2 further including the step of

(g) monitoring the outbound communications channel before placing a data message on the inbound channel;

and

(h) detecting and counting the number of outbound messages observed on the outbound channel;

(i) pausing for a period, said period equal to the product of the time period of a single acknowledgement message times the counted number of outbound messages; and

(j) transmitting said inbound data message at the expiration of said pause period.