Dynamic data link segmentation and reassembly

This application claims the benefit of the following U.S. Provisional Patent Applications, each of which is incorporated by reference herein in its entirety:

U.S. App. No. 60/976,730 filed on Oct. 1, 2007;

U.S. App. No. 60/976,735 filed on Oct. 1, 2007;

U.S. App. No. 60/976,740 filed on Oct. 1, 2007;

U.S. App. No. 60/976,744 filed on Oct. 1, 2007;

U.S. App. No. 60/976,747 filed on Oct. 1, 2007; and

U.S. App. No. 60/976,748 filed on Oct. 1, 2007.

This invention was made with support of the United States Government under Contract MDA972-01-9-0022. The United States Government may have certain rights in the invention.

This invention relates to physical layer communications in a Mobile Ad Hoc Network (MANET), and more particularly to dynamic segmentation and reassembly of data packets in a data link of a MANET. There remains a need for improved physical layer handling of data in wireless ad hoc networks, particularly where traffic of varying types and priorities are exchanged over dynamically changing data links.

In a Mobile Ad Hoc Network (MANET), Dynamic Data Link Segmentation and Reassembly (SAR) functions perform a large packet to small packet transformation and reassembles packets at a receiving node. The packet size is determined dynamically in response to link quality data for each individual data link. By periodically sharing link quality information with neighbors, the segmentation size and corresponding reassembly can be performed using readily available neighborhood and waveform information.

In one aspect, a method that is disclosed herein includes providing a data item for transmission from a first node to a second node over a data link in an ad hoc wireless network, the data item having a length; determining a link quality of the data link; selecting a transmit mode for the data link according to the link quality, the transmit mode including a data rate; determining a payload length for the data link according to the data rate; segmenting the data item into one or more segments according to the payload length; and transmitting the one or more segments as one or more packets over the data link.

In one aspect, a device that is disclosed herein includes a data source that provides data; a data link that packetizes data from the data source into a packet; a radio that provides an air interface to a mobile ad hoc network including a link to a neighboring node; and a signal processor that prepares the packet for transmission over the air interface, the signal processor adapted to dynamically segment the packet into one or more segments according to a data rate for the link.

In one aspect, a computer program product that is disclosed herein performs the steps of providing a data item for transmission from a first node to a second node over a data link in an ad hoc wireless network; determining a link quality of the data link; selecting a transmit mode for the data link according to the link quality, the transmit mode including a data rate; determining a payload length for the data link according to the data rate; segmenting the data item into one or more segments according to the payload length; and transmitting the one or more segments as one or more packets over the data link.