Method and system for reliable data transmission in wireless networks

• US 20070076745A1
• Filed: 09/30/2005
• Published: 04/05/2007
• Est. Priority Date: 09/30/2005
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Srinivasan, Bhaskar, Venkatraman, Lakshmi, Manjeshwar, Arati
• Granted Patent: US 7,613,146 B2
• Time in Patent Office: Days
• US Class Current: 370/448
• CPC Class Codes: H04L 1/1803 Stop-and-wait protocols
• CPC Class Codes: H04L 1/22 using redundant apparatus to increase reliability
• CPC Class Codes: H04W 74/0808 using carrier sensing, e.g. carrier sense multiple access [CSMA]

Abstract

A method for transmitting data from a sender node from among at least one sender node to a receiver node in a wireless network, the method including (a) sampling, by the receiver node, in each time slot, a main network frequency and at least one backup frequency, (b) transmitting, by the sender node, a message on the main network frequency in a first time slot, without using a multiple access protocol, (c) transmitting, by the sender node, the message on the main network frequency in a next time slot, using the multiple access protocol exchange, if an acknowledgement of the message is not received from the receiver node, (d) transmitting, by the sender node, the message on at least one backup frequency in the next time slot, using a multiple access protocol, if the main network frequency is busy after performing step (c), (e) repeating steps (c) and (d) for a predefined number of time slots, unless or until an acknowledgement is received from the receiver node, (f) transmitting, by the sender node, the message on each backup frequency, using the multiple access protocol, unless or until an acknowledgment is received from the receiver node, and (g) performing an exponential backoff and subsequent transmission of the message, by the sender node, if an acknowledgement is still not received from the receiver node after performing steps (a) through (f)

Claims

1. A method for transmitting data from a sender node from among at least one sender node to a receiver node in a wireless network, the method comprising:

(a) sampling, by the receiver node, in each time slot, a main network frequency and at least one backup frequency;

(b) transmitting, by the sender node, a message on the main network frequency in a first time slot, without using a multiple access protocol;

(c) transmitting, by the sender node, the message on the main network frequency in a next time slot, using the multiple access protocol exchange, if an acknowledgement of the message is not received from the receiver node;

(d) transmitting, by the sender node, the message on at least one backup frequency in the next time slot, using a multiple access protocol, if the main network frequency is busy after performing step (c);

(e) repeating steps (c) and (d) for a predefined number of time slots, unless or until an acknowledgement is received from the receiver node;

(f) transmitting, by the sender node, the message on each backup frequency, using the multiple access protocol, unless or until an acknowledgment is received from the receiver node; and

(g) performing an exponential backoff and subsequent transmission of the message, by the sender node, if an acknowledgement is still not received from the receiver node after performing steps (a) through (f).

2. The method of claim 1, wherein the multiple access protocol includes the Carrier Sense Multiple Access (CSMA) protocol.

3. The method of claim 1, wherein the at least one sender node and receiver node are synchronized according to the Time Division Multiple Access (TDMA) protocol.

4. The method of claim 1, wherein the message is transmitted in step (c) upon an occurrence of an event.

5. The method of claim 4, wherein the event includes an alarm.

6. The method of claim 1, wherein step (g) further includes:

choosing, by the sender node, a random number; and

transmitting the message in a time slot based on the chosen random number.

7. The method of claim 1, wherein a range of random numbers to choose from depends on a number of at least one of available time slots and available frequencies.

8. The method of claim 7, wherein the number of available time slots is adjusted based on a number of failed transmission attempts.

11. The method of claim 1, wherein the at least one sender node and receiver node are synchronized according to the Time Division Multiple Access (TDMA) protocol.

12. The method of claim 1, wherein the message is transmitted in step (c) upon an occurrence of an event.

9. The method of claim 9, wherein for every failed transmission attempt, the number of available time slots is increased by a factor of two.

10. A method for transmitting data from a sender node from among at least one sender node to a receiver node in a wireless network, the method comprising:

(a) sampling, by the receiver node, in each time slot, a main network frequency and at least one backup frequency;

(b) transmitting, by the sender node, a message on the main network frequency in a first time slot, without using a Carrier Sense Multiple Access (CSMA) protocol;

(c) transmitting, by the sender node, the message on the main network frequency in a next time slot, using the Carrier Sense Multiple Access (CSMA) protocol, if an acknowledgement of the message is not received from the receiver node;

(d) transmitting, by the sender node, the message on at least one backup frequency in the next time slot, using the Carrier Sense Multiple Access (CSMA) protocol, if the main network frequency is busy after performing step (c);

(e) repeating steps (c) and (d) for a predefined number of time slots, unless or until an acknowledgement is received from the receiver node;

(f) transmitting, by the sender node, the message on each backup frequency, using the multiple access protocol, unless or until an acknowledgment is received from the receiver node; and

(g) performing an exponential backoff and subsequent transmission of the message, by the sender node, if an acknowledgement is still not received from the receiver node after performing steps (a) through (f), wherein the sender node chooses a random number and transmits the message in a time slot based on the chosen random number, a range of random numbers to choose from depends on a number of at least one of available time slots and available frequencies,

wherein the number of available time slots is adjusted based on a number of failed transmission attempts and for every failed transmission attempt, the number of available time slots is increased by a factor of two.

13. A method for transmitting data in a wireless network, the method comprising:

(a) sampling, in each time slot, at least one network frequency;

(b) transmitting a message on a first network frequency in a first time slot;

(c) transmitting the message on the first network frequency in a next time slot if an acknowledgement of the message is not received;

(d) transmitting the message on at least one other network frequency in the next time slot if the first network frequency is busy after performing step (c);

(e) repeating steps (c) and (d) for a predefined number of time slots, unless or until an acknowledgement of the message is received;

(f) transmitting the message on each of the network frequencies, unless or until an acknowledgment of the message is received; and

(g) performing an exponential backoff and subsequent transmission of the message if an acknowledgement of the message is still not received after performing steps (a) through (f).

14. A method for transmitting data in a wireless network, the method comprising:

(a) transmitting a message on a first network frequency in a first time slot;

(b) transmitting the message on the first network frequency in a next time slot if an acknowledgement of the message is not received;

(c) transmitting the message on at least one other network frequency in the next time slot if the first network frequency is busy after performing step (c);

(d) repeating steps (b) and (c) for a predefined number of time slots, unless or until an acknowledgement of the message is received; and

(e) performing an exponential backoff and subsequent transmission of the message if an acknowledgement of the message is still not received after performing steps (a) through (d).