Scheduling the transmission of messages on a broadcast channel of an ad-hoc network dependent on the usage of this channel

• US 20090185489A1
• Filed: 07/18/2005
• Published: 07/23/2009
• Est. Priority Date: 07/22/2004
• Status: Abandoned Application

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: NXP B.V. (NXP Semiconductors NV)
• Inventors: Van Wageningen, Andries, Ruffini, Marco
• Application Number:
  US11/658,226
• Publication Number:
  US 20090185489A1
• Time in Patent Office: Days
• US Class Current: 370/237
• CPC Class Codes: H04L 12/189 in combination with wireless systems selective distribution or broadcast in wireless communication networks H04W4/06
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/11 Identifying congestion
• CPC Class Codes: H04L 47/12 Avoiding congestion; Recovering from congestion
• CPC Class Codes: H04L 47/24 Traffic characterised by specific attributes, e.g. priority or QoS
• CPC Class Codes: H04L 47/50 Queue scheduling
• CPC Class Codes: H04W 28/02 Traffic management, e.g. flow control or congestion control
• CPC Class Codes: H04W 28/10 Flow control between communication endpoints
• CPC Class Codes: H04W 72/54 based on quality criteria
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

In order to provide a communication system (100) as well as a method of communication between and among mobile nodes (10, 12, 14, 16), in particular between and among vehicles, with each node (10, 12, 14, 16) sending at least one message (24, 26) via at least one broadcast channel (18) and receiving at least one arriving message (34, 36) being sent by at least one neighboring node (12, 14, 16) via the broadcast channel (18), wherein the access to the broadcast channel (18) is regulated, a certain equity in the bandwidth subdivision is guaranteed and network overloading is prevented, it is proposed that the transmission of the messages (24, 26) is scheduled dependent on the usage of the broadcast channel (18), in particular dependent on the load of the broadcast channel (18), the S[ignal]/N[oise] ratio on the broadcast channel (18), and/or the contents and/or type of messages (34, 36) received via the broadcast channel (18).

Claims

1. Communication system for communication between and among mobile nodes in particular between and among vehicles, each node comprising

at least one sender unit for transmitting at least one message via at least one broadcast channel as well as

at least one receptor unit for sensing at least one message being sent by at least one neighboring node via the broadcast channel, characterized in that the transmission of the messages is scheduled dependent on the usage of the broadcast channel in particular dependent on

the load of the broadcast channel

the S[ignal]/N[oise] ratio on the broadcast channel and/or the contents and/or type of messages received via the broadcast channel

2. Communication system according to claim 1, characterized by at least one scheduling unit being provided by at least one channel occupation detection unit with at least one parameter, in particular

at least one bandwidth occupation coefficient (a) and/or

at least one S[ignal]/N[oise] ratio coefficient (β

), said scheduling unit calculating the maximum overall message rate for each node

fulfilling the Q[uality]o[flS[ervice] requirements expressed in QoS parameters such as

maximum delay,

delay variance and/or

bandwidth guarantee,

under the condition of the calculated maximum overall message rate storing each message temporarily in at least one queuing list and

notifying at least one message generating unit

when the message is successfully transmitted via at least one

C[arrier]S[ense]M[ultiple]A[ccess]/C[ollision]A[voidance] device or

if the transmission of the message has failed.

3. Communication system according to claim 2, characterized in that

the message generating unit is designed for generating

hello messages as related to safety purposes,

warning messages as related to safety purposes and

data messages as related to general purposes, and

in that the overall available bandwidth is subdivided between these three types

of messages on the basis of information as supplied from the application level.

4. Communication system according to claim 1, characterized by at least one message analyzing unit

for decoding the messages provided by the neighboring nodes and

for processing these decoded messages to supply the information, for example about the number (N) of detected nodes in the neighborhood, to at least one Q[uality]o[flS[ervice] parameter generating/regulating unit

wherein the information about the number of detected neighboring nodes is retrievable by considering the number of hello messages received with different identification number within a certain range.

5. Communication system according to claim 4, characterized in that the QoS parameter generating regulating unit calculates the QoS requirement parameters for the scheduling unit on the basis of information received

from the message analyzing unit and

from at least one local situation analyzing unit taking into account, for example, the speed of the node.

6. Communication system according to claim 4, characterized by at least one external message receiver unit for sending the messages correctly sensed by the receptor unit to the message analyzing unit.

7. Method of communication between and among mobile nodes in particular between and among vehicles, with each node

sending at least one message via at least one broadcast channel and

receiving at least one arriving message being sent by at least one neighboring node via the broadcast channel

characterized in that the transmission of the messages is scheduled dependent on the usage of the broadcast channel in particular dependent on

the load of the broadcast channel,

the S[ignal]/N[oise] ratio on the broadcast channel and/or

the contents and/or type of messages received via the broadcast channel.

8. Method according to claim 7, characterized in that

the messages are distinguished into three different kinds of messages, called

hello messages

warning messages and

data messages and

in that the overall available message rate is subdivided into three different subrates, whose respective value is dependent on information retrieved

from external messages and

from a situation analysis.

9. Method according to claim 7, characterized

by the disposal of bandwidth being regulated in the case of revelation of at least one “

dispose bandwidth”

message in the broadcast channel as well as

by the normal bandwidth partition being restored between the nodes.

10. Use of at least one communication system according to and/or of the method according to claim 7 for wireless adhoc networks, in particular for automotive or car-to-car communication, wherein cars

interact cooperatively and distribute for example warning messages especially

in order to avoid collisions during lane change or merge manoeuvres and

for reporting of invisible obstacles, for example obscured or shadowed objects, when vehicles are moving in different directions within the same area.

11. Mobile node for a communication system the node comprising

at least one sender unit for transmitting at least one message via at least one broadcast channel as well as

at least one receptor unit for sensing at least one message being sent by at least one neighbouring node via the broadcast channel characterized in that the transmission of the messages is scheduled dependent on the usage of the broadcast channel in particular dependent on

the load of the broadcast channel

the S[ignal]/N[oise] ratio on the broadcast channel and/or

the contents and/or type of messages received via the broadcast channel