Metricom, Inc.

Metricon, Inc.

George H Flammer

Brett D Galloway

Robert L Kalkwarf

Paul Baran

David L Paulsen

Michael W Ritter

John Bettendorff

Robert P Dilworth

William E San Filippo, Iii

A large data file is distributed to a number of nodes in a data communication network by a process of distributed downloading. Destination nodes are informed of the location in the network of the large data file and are directed to receive the large data file by requesting that blocks of data containing the file be transmitted to them from the designated source node. The destination nodes control the file transfer. The large data file may contain program code for updating network software.

Method for distributing program code to intelligent nodes in a wireless

In a packet communication system, loose source routing is employed to permit communication over networks of disparate types, including geographic and path-unaware types. No information resides on a wired access point (WAP). All of the intelligence of the system resides in Name Servers, which provide opaque addresses that end nodes (radios) in a wireless cloud can use to send packets to other end nodes (radios) in other wireless clouds. (A cloud is the set of radios serviced by a particular WAP.) According to the invention, the method employs an ordered list called a path and the network address of a packet consists of such an ordered list of addresses with a 'marker' that flags the current destination of the packet and a 'direction bit' that tells which direction on the list the next destination is. Each address in the path is type-length-value (TLV) encoded. The address has preferably a 4 bit 'type' field, followed by a 4 bit 'length' field (indicating length in words) of the value, and then the actual 'value' of the address. Each address describes a 'place' that the packet must 'visit.' These 'places' may be areas which a packet must traverse, and not necessarily actual node addresses.

Method of loose source routing over disparate network types in a packet

In a wireless packet communication system having a plurality of nodes, each having a transmitter and a receiver, the receiver at each node is assigned a seed value and is provided with a channel punchout mask. A node uses its seed value and punchout mask to generate a specific randomly ordered channel hopping band plan on which to receive signals. A node transmits its seed value and punchout mask to target nodes with which it wants to establish communication links, and those target nodes each use the seed value and punchout mask to generate the randomly ordered channel hopping band plan for that node. Subsequently, when one of the target nodes wish to transmit to the node, the target node changes frequency to the frequency of the node according to that node's band plan.

Method for frequency sharing and frequency punchout in frequency hopping

In a packet communication system, wherein nodes are assigned an absolute coordinate-based address and routing decisions are made at each node without the use of directory-based routing, routing decisions made for a particular packet with an ultimate destination are stored at each node so that the next packet sent by that node to that same ultimate destination can be forwarded in accordance with the previous routing decision made for that destination. Routing decisions are stored locally at each node in a routing table. In one embodiment, nodes also store routing information about the source node for a packet so that when a return packet is received for the original source, the relay node will not have to make a routing decision.

Method and system for routing packets in a packet communication network

A microcellular digital packet communication system is provided for digital communication having a plurality of repeating packet-mode fixed-site transceivers each being at a plurality of different sites and each being capable of communicating on mutually-common frequencies, including for example by means of frequency-hopping spread spectrum, wherein a terminal transceiver directly communicates substantially simultaneously with at least a few of the fixed-site transceivers on the mutually-common frequencies and distributes information packets of a single originating message among the fixed-site transceivers, the fixed-site transceivers forwarding the information packets via multiple communication links to a single destination terminal on the mutually-common frequencies at which the message is reassembled. The system enables reliable handoffs and robust connectivity by maintaining multiple simultaneous communication links between terminal transceivers and repeating transceivers.

Transceiver sharing between access and backhaul in a wireless digital

In a wireless packet communication system having a plurality of nodes, each having a transmitter and a receiver, the receiver at each node is assigned a specific frequency hopping band plan on which to receive signals, and the transmitter of any source node desiring to communicate with a target node changes frequency to the frequency of the target node according to the band plan. Thereupon, the source node transmits a poll packet which polls the target node to determine whether the target node is able and willing to accept a specified number of packets, at a specified level of priority. A failure to receive an acknowledgement on the source node's receive channel is a prompt to the source node either to retransmit a polling packet later, to change the polling packet or to redirect the polling packet to another target. In the event the target node returns an acknowledgement, the target node reserves access to itself for the polling station at a determined time for a determined duration. The source node then transmits its data packet on the target node receive channel and waits for an acknowledgement on its own receive channel. The source node and the target node exchange information on the agreed upon data exchange channel, even though the expected receive channel according to the frequency hopping band play of the target node may have changed in the meantime.

Method of resolving media contention in radio communication links

In a wireless LAN packet communication system, for each successfully received packet the strength of the received signal is measured at a target node by monitoring an A/D converted rssi (received signal strength indication) signal. A record of minimum strength among successfully received packets is maintained at the target node. For each succesfully received packet the difference between the signal strength of the packet and the recorded minimum is calculated at the target node and sent over the link to the source node as a quantitative difference indicator. The source node maintains a moving average of difference indicators received over time and adjusts the transmitter power level so as to maintain the moving average at a preselected link margin threshold level. Alternatively, the calculation of a desired source node power level change is performed at the target node and transmitted to the source node.

Automatic power level control of a packet communication link

In a mesh communication network, new network nodes acquire information about nearby nodes to which they may communicate through a third-party query whereby an established node with which a new node can communicate is queried to provide a list of nodes in the vicinity of the new nodes with which the new node is likely to be able to communicate. The new node uses this list in attempting to establish communication links and then repeats the third-party query for each node in the list to which it can communicate.

Method for network configuration via third party query

In a packet communication system wherein stationary nodes are assigned an absolute coordinate-based address, the addressing of roaming nodes is accomplished by parasitically adopting a coordinate routing scheme used for addressing stationary nodes. Each roaming node selects a parent stationary node with which the roaming node can communicate directly. During the course of network operation, the roaming node may select a new parent node. At the time of reassignment, the coordinates of the new parent node, along with the identity of the roaming node, is recorded at the former parent node. Forwarding of packets to stationary nodes is accomplished according to a known coordinate-based routing scheme. A packet addressed to a destination roaming node is forwarded and directed through the then current stationary parent node. The packet is then forwarded to the destination roaming node.

Parasitic adoption of coordinate-based addressing by roaming node

A frequency-hopping packet communication system without a master clock or master control unit is based on use of a receiver's frequency hopping timing and identification to control communication. A frequency-hopping band plan, involving the number of channels and the pseudo-random pattern of frequency change and nominal timing of changes, is universally known to each node in the network. A transmitter acquires synchronization with a target node by use of information previously received from or about a target indicating timing of present idle frequency hop of the target receiver. Each receiving node establishes in each station or node a table of receiver frequency hopping sequence offsets (hop timing offsets) of each other node within its communication range, and each node announces its presence on each frequency in a packet with a hop timing offset indicator. The hop timing offset indicator is a key used to read a table to allow nodes to set themselves in synchronization with one another. A location indicator built into the address of each packet is used to randomize an ordered frequency-hopping table at each node. Frequency-hopping is implemented by the division of communicaton slots and the accumulation of slots into epochs, wherein each epoch equals the total number of available slots (number of channels times the number of time frames per channel). The transmitting node tracks the pre-established frequency-hopping pattern for its target receiver based on previously-acquired information.

Method for synchronizing a wide area network without global synchronizing

A packet network routing method and system based on geographic coordinate identifiers is described. Each node in a network is uniquely identified by absolute geographical coordinates or by a code indicating absolute location in an external coordinate-based reference system (node coordinates), and such absolute geographical coordinates or the equivalent are employed as part of a packet identifier for each packet generated for use in making routing decisions. The node coordinates of a local node and its neighboring nodes and the packet coordinates are used by means at each node through which a packet is routed for determining a desired forwarding route of a data packet. The routing may be prioritized according to preselected criteria, preferably achieving maximum forward progress using the least amount of power. The packet routing protocol according to the invention requires no routing directory or table to perform data routing.

A frequency-hopping packet communication system without a master clock or master control unit is based on use of a receiver's frequency hopping timing and identification to control communication. A frequency-hopping band plan, involving the number of channels and the pseudo-random pattern of frequency change and nominal timing of changes, is universally known to each node in the network. Frequency-hopping is implemented by the division of communication slots and the accumulation of slots into epochs, wherein each epoch equals the total number of available slots (number of channels times the number of time frames per channel). A transmitting node tracks the preestablished frequency-hopping pattern for its target receiver based on previously-acquired information. The transmission node identifies a receiver node and a current frequency channel of such receiver node. The transmission node then checks the frequency channel to determine if available (e.g., not in use and within an acceptable noise margin). If unavailable, the transmission node delays transmission to the identified node to a later slot. During the delay, the transmission node identifies another receiver node and a corresponding current frequency channel. The steps of identifying a receiver node and checking the corresponding current frequency channel are repeated until a node having an available frequency channel is identified. The transmission node then sends a packet to the selected receiver node at a frequency and for a duration defined according to the current slot. Such transmission node tracks the changing frequency of the selected receiver node to maintain frequency synchronization.

Method for frequency sharing in frequency hopping communications network

A technique is provided whereby broadcast or flooding packets received at a node are only rebroadcast if specific criteria are met. The criteria are based on a packet routing protocol wherein sequence information is maintained at each node on a link basis for each received packet and wherein received packets are rebroadcast only to other nodes with low sequence numbers. Each node maintains information on each other node within its communication range and assigns a link sequence number to the linked node at the time of the first exchange of a link information packet. Each node works backwards from the information sent to it to determine which other nodes should receive rebroadcast packets. In a packet flooding situation, a node rebroadcasts a flooding packet only to those other nodes which have low sequence numbers or for which the rebroadcasting node is a low sequence number of the other node.

Method for routing packets by squelched flooding

A packet network routing method and system based on geographic coordinate identifiers is described. Each node in a network is uniquely identified by absolute geographical coordinates or by a code indicating absolute location in an external coordinate-based reference system (node coordinates), and such absolute geographical coordinates or the equivalent are employed as part of a packet identifier for each packet generated for use in making routing decisions. The node coordinates of a local node and its neighboring nodes and the packet coordinates are used by means at each node through which a packet is routed for determining a desired forwarding route of a data packet. The routing may be prioritized according to preselected criteria, preferably achieving maximum forward progress using the least amount of power. The packet routing protocol according to the invention requires no routing directory or table to perform data routing. Each node of the network collects in a table or is otherwise provided with information about the quality of communication between itself and its neighboring nodes. When a data packet has been received at a node, it is routed further through the network based on criteria derived from the history of communication between the local node and its neighbors.

Growing community of inventors

Cupertino, CA, United States of America

George H Flammer