Time reservation using adaptive control for energy efficiency

• US 20040184477A1
• Filed: 03/20/2003
• Published: 09/23/2004
• Est. Priority Date: 03/20/2003
• Status: Active Grant

• Current Assignee: University of Rochester
• Original Assignee: University of Rochester
• Inventors: Heinzelman, Wendi, Tavli, Bulent
• Granted Patent: US 7,764,706 B2
• Time in Patent Office: Days
• US Class Current: 370/461
• CPC Class Codes: H04W 28/26 Resource reservation
• CPC Class Codes: H04W 48/12 using downlink control channel
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 52/0219 where the power saving management affects multiple terminals
• CPC Class Codes: H04W 84/20 Master-slave selection or change arrangements
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A network, such as a radio network, uses dynamic transmission scheduling and soft clustering. When nodes contend for data slots, each node that is successful continues to have its data slot reserved for it until it sets an end-of-stream bit in an information summarization packet, indicating that it will stop broadcasting. From the information summarization packets, each node determines the other nodes to which it will listen, based on proximity and information content.

Claims

1. A method for transmitting information in a network having a plurality of nodes, one of which is a controller node, the method comprising:

(a) dividing time into frames, each frame comprising (i) a beacon slot for sending a beacon, (ii) a plurality of contention slots for sending requests for data slots, (iii) a header slot for sending a header which comprises a transmission schedule for the frame, (iv) a plurality of information summarization slots for sending summaries of the information, and (v) a plurality of data slots, each for data transmission by one of the nodes;

(b) permitting each of the plurality of nodes to reserve one of the plurality of data slots by sending the requests in the contention slots;

(c) maintaining a reservation of each of the plurality of data slots which is reserved by one of the plurality of nodes until said one of the plurality of nodes indicates that it has stopped transmitting;

(d) sending the header from the controller node, the transmission schedule in the header indicating the reservations; and

(e) sending the information from the nodes in accordance with the transmission schedule.

2. The method of claim 1, wherein, in step (b):

the nodes transmit the requests to reserve data slots;

in an absence of collision, the controller node assigns the data slots to the nodes and broadcasts the transmission schedule indicating assignments of the data slots to the nodes; and

if a node which has requested a data slot is not listed in the transmission schedule, the node retransmits its request.

3. The method of claim 1, wherein when the controller node fails, another node becomes the controller node and operates as the controller node using the transmission schedule.

4. The method of claim 3, wherein the transmission schedule is used as a list of backup nodes in hierarchical order.

5. The method of claim 1, wherein:

each node sends an information summarization packet during a corresponding one of the information summarization slots; and

each node indicates that it has stopped transmitting by sending an end-of-transmission bit in its information summarization packet.

6. The method of claim 5, wherein:

each node records a power level of the information summarization packet sent by each of a plurality of other nodes to determine a listening cluster of nodes based at least partially on proximity; and

said each node listens to the nodes in the listening cluster.

7. The method of claim 6, wherein:

each node receives the information summarization packets sent by the nodes in its listening cluster, determines in accordance with the information summarization packets which information it wishes to receive, and listens only to the nodes sending the information that it wishes to receive.

8. The method of claim 1, wherein each of the nodes in the network is assigned a priority from among a plurality of priorities, and wherein, when the network does not have sufficient capacity to permit all of the nodes to transmit the information, packets from the nodes having a highest priority are given preference.

9. The method of claim 1, wherein, at startup:

a node listens for transmissions during a predetermined time period;

if the transmissions are not detected during the predetermined time period, the node selects a random time at which to transmit its own beacon;

if, within the random time, the node hears the beacon from another node, the node starts normal operation; and

if, within the random time, the node does not hear the beacon from another node, the node transmits the beacon and functions as the controller node.

10. A device for operating as a node in a network having a plurality of nodes, one of which is a controller node, the network dividing time into frames, each frame comprising (i) a beacon slot for sending a beacon, (ii) a plurality of contention slots for sending requests for data slots, (iii) a header slot for sending a header which comprises a transmission schedule for the frame, (iv) a plurality of information summarization slots for sending summaries of the information, and (v) a plurality of data slots, each for data transmission by one of the nodes, the device comprising:

a communication component for communicating with a plurality of other devices within the network; and

a processor, operatively connected to the communication component, for controlling an operation of the communication component such that the device performs the following operational steps;

(a) permitting the node to reserve one of the plurality of data slots by sending the request in one of the contention slots;

(b) if the request is granted, maintaining a reservation of one of the plurality of data slots until the reservation is no longer needed, and setting an end-of-stream bit in a packet in a corresponding information summarization slot indicating that the reservation is no longer needed;

(c) receiving the header from the controller node, the transmission schedule in the header indicating the reservations; and

(d) sending the information in accordance with the transmission schedule.

11. The device of claim 10, wherein, at startup, the processor further controls the communication component to perform the following operational steps:

(e) listening for transmissions during a predetermined time period;

(f) if the transmissions are not detected during the predetermined time period, selecting a random time at which to transmit its own beacon;

(g) if, within the random time, the device hears the beacon from another node, starting normal operation; and

(h) if, within the random time, the device does not hear the beacon from another node, transmitting the beacon and functions as the controller node.

12. The device of claim 10, wherein, when the controller node fails, the processor further controls the communication device such that the device functions as the controller node in accordance with a list of backup nodes.

13. The device of claim 12, wherein the list of backup nodes is based on the transmission schedule.

14. A method for transmitting information in a network having a plurality of nodes, one of which is a controller node, the method comprising:

(a) dividing time into frames, each frame comprising a plurality of data slots, each for data transmission by one of the nodes;

(b) permitting each of the plurality of nodes to reserve one of the plurality of data slots;

(c) maintaining a reservation of each of the plurality of data slots which is reserved by one of the plurality of nodes until said one of the plurality of nodes indicates that it has stopped transmitting;

(d) sending a transmission schedule indicating the reservations from the controller node; and

(e) sending the information from the nodes in accordance with the transmission schedule.