GB2415855A - Variable network address lengths - Google Patents

Variable network address lengths Download PDF

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Publication number
GB2415855A
GB2415855A GB0414940A GB0414940A GB2415855A GB 2415855 A GB2415855 A GB 2415855A GB 0414940 A GB0414940 A GB 0414940A GB 0414940 A GB0414940 A GB 0414940A GB 2415855 A GB2415855 A GB 2415855A
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Prior art keywords
accordance
devices
communication
address
network
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GB0414940A
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GB0414940D0 (en
GB2415855B (en
Inventor
Dimitrios Skraparlis
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Toshiba Europe Ltd
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Toshiba Research Europe Ltd
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Priority to GB0414940A priority Critical patent/GB2415855B/en
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Publication of GB2415855A publication Critical patent/GB2415855A/en
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Publication of GB2415855B publication Critical patent/GB2415855B/en
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Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L45/00Routing or path finding of packets in data switching networks
    • H04L12/5689
    • H04L29/08108
    • H04L29/08675
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L45/00Routing or path finding of packets in data switching networks
    • H04L45/74Address processing for routing
    • H04L45/742Route cache; Operation thereof
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L61/00Network arrangements, protocols or services for addressing or naming
    • H04L61/50Address allocation
    • H04L61/5038Address allocation for local use, e.g. in LAN or USB networks, or in a controller area network [CAN]
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L67/00Network arrangements or protocols for supporting network services or applications
    • H04L67/01Protocols
    • H04L67/04Protocols specially adapted for terminals or networks with limited capabilities; specially adapted for terminal portability
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L67/00Network arrangements or protocols for supporting network services or applications
    • H04L67/50Network services
    • H04L67/535Tracking the activity of the user
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L2101/00Indexing scheme associated with group H04L61/00
    • H04L2101/60Types of network addresses
    • H04L2101/618Details of network addresses
    • H04L2101/622Layer-2 addresses, e.g. medium access control [MAC] addresses
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L2101/00Indexing scheme associated with group H04L61/00
    • H04L2101/60Types of network addresses
    • H04L2101/672Short addresses
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W8/00Network data management
    • H04W8/26Network addressing or numbering for mobility support

Abstract

A communications network operates to conduct the communication of packet based data between communication devices of the network. Local addressing is implemented, to ease the addressing of devices, and to avoid the need to use the full length 6 Byte source and destination Media Access Control (MAC) addresses. Address length is variable, on the basis of previously recorded activity between two devices in communication. Address length control is effected by messages held in pre-allocated areas of a packet of data. The shorter local addresses tend to be allocated to more frequently addressed devices, whereby distinct addresses are allocated in accordance with said address length allocation. Application is suitable for wireless networks where energy consumption resulting from data transfer may be an important factor.

Description

Communications Apparatus Providing Local Addressing This invention relates
to a communication apparatus for use m a network, and also to a method for conducting communication in a network. The invention is particularly, but not exclusively, related to communication m a wireless communications network.
In wireless communications networks adhering to internationally agreed standards, medium access control (MAC) addresses are typically assigned to communications devices, selected from a pre-determined list. Naturally, for a widely accepted communications standard, a very high number of MAC addresses must be made available to ensure that all present and predicted devices manufactured according to the standard can potentially communicate with other similarly configured devices.
For example, MAC addresses conventionally abide to the IEEE802.3 Ethernet standard.
This specifies globally unique addresses of 48 bits. This enables 2A48 devices to be allocated individual and unique addresses, so that any device can be introduced into any wireless network without any possibility of conflict. A communications system using the IEEE802. 1 1 standard uses this 48 bit MAC address system to direct frames within a wireless LAN.
This range of addresses has been selected with the possibility that the anticipated maximum number of devices which could ever be produced globally to a particular communication standard could all be identified uniquely. However, using long addresses in a communications system is not desirable as, for example, it is very unlikely ever to be necessary to be able to address all devices. For environments where devices are assembled into a piconet, but are then retained in a fixed configuration (for example in a domestic residence), the number of participating terminals is fixed and very small in relation to the maximum number of devices that 48 bit addresses provide.
The Bluetooth communications standard provides the possibility for 3 bit active addresses to be allocated while connecting in a piconet. However, the consequence of using a 3 bit active address field is that the number of tenninals that can be accommodated in such a Pico net is limited to 7, as the zero address (000) is reserved.
This may be inconveniently small in some circumstances, requiring the use of dynamic parking and unpacking mechanisms to support more devices. This process can be complex and inefficient as it requires control information to be exchanged between nodes in the network, which may decrease the rate of data throughput in the network.
Further, in wireless sensor networks comprising hundreds or thousands of battery powered autonomous devices, able to communicate only at short range, energy consumption is a substantial perfonnance limiting factor, and the use of 48 bit MAC headers during communication between the nodes can represent an important source of energy consumption.
As illustrated in Figure 1, a physical layer data packet 10 in accordance with the IEEE802.1 la standard includes a preamble 12, a signal field 14 and a data field 16. The signal field 14 is one OFDM symbol in duration and the data field can be a variable number of OFDM symbols in duration, depending on the amount of data that the data field l 6 contains. The signal field 14 comprises 4 bits defining data rate 20 at which the physical layer communications protocol of the device should transmit the data contained in the packet. Then, a single reserved bit 22 separates the rate bits from a 12 bit length field which is used to indicate the number of octets (S bit words) in the MPDU which the MAC is currently requesting the PHY layer to transmit. This value is used by the PHY to determine the number of octet transfers that will occur between the MAC and the PHY after receiving a request to start the transmission. A parity bit 26 then follows, then a 6 bit tail portion 28 completes the signal field 14.
The data field 16 comprises a service field 30, which is often considered as part of a header portion of the packet 10 along with the signal field 14. The service field 30 is 16 bits in length, of which the first 7 bits are set to zero and will be used to synchronise the descrambler in a receiver receiving the packet 10. In the IEEE802.11 a standard, the remaining 9 bits of the service field have not been assigned but may be in future versions of the standard. These reserve bits are set to zero to avoid unexpected results.
A physical sub-layer service data unit (PSDU) 32 follows the service field 30, and is of a length which enables data to be contained for transmission in the packet 10. Thus, the PSDU 32 is of variable length from packet to packet. Following the PSDU 32 Is a tail 34, 6 bits in length and a number of padding bits 36 if required to bring the total number of bits in the data field 16 to an integer multiple of OFDM symbols.
Figure 2 illustrates the structure of the PSDU 32 illustrated in the packet 10 of Figure 1.
The PSDU 32 commences with a two byte frame control portion 40 which carries MAC layer control infonnation such as indicating the frame type (for example an RTS, CTS or ACK frame) or passing control information (for example indicating retransmissions or passing power management information). A two byte duration portion 42 contains a duration value which provides a predicted time needed for the current transaction to complete. This can, for example, be expressed in multiples of a fixed and predetermined number of microseconds.
For example, if the packet under consideration is one in a sequence of command frames, such as an RTS, CTS, DATA or ACK frame sequence taking account of short interframe spacings (SIFS), and during which a node not participating in the transaction can remain idle and wait for the next contention period, a node can determine that the medium is idle through the use of the carrier sense function for the interval specified as SIFS.
Then, a destination address portion 44, which is conventionally 6 bits in length specifies the destination address of the packet 10 to which the data is to be forwarded, and correspondingly a source address portion 46 specifies, in a 6 byte value, the source of the packet 10. The frame body 48 follows the source address; this is not of fixed length, and may indeed not be included in the case of certain control packets on which data is not carried. Finally, a frame check sequence (FCS) 50, 4 bytes in length, provides means by which the remainder of the packets may be checked for example by CRC, for any transmission errors, as it provides the result to a predetermined binary calculation that the receiver can perform upon the received data.
Therefore, m the case of a system configured to transfer data between nodes in accordance with the packet structure Illustrated in Figures 1 and 2, each packet must contain 12 bytes of information, namely the Destination address portion 44 and the Source address portion 46, defining the source and destination of the packet being transferred, in espective of the number of nodes in the system. This information is, in absolute terms a substantial overhead once several packets of this structure require transmission; also in relative terms if little data is to be transmitted, then the address information contained in the 12 bytes may be disproportionately high compared with the amount of data to be transmitted.
To further illustrate this, an RTS frame is illustrated in the same manner in Figure 3, a CTS frame in Figure 4, a DATA frame in figure 5 and an ACK frame in Figure 6. In the case of the CTS frame illustrated in figure 4 and the ACK frame illustrated in figure 6, the Source address field is omitted as unnecessary to the conduct of communication; however, the same issue relating to the overhead associated with the length of the destination address field remains relevant. In the case of the DATA frame illustrated in figure 5, four address fields are allocated, each being 6 bits in length, thus exacerbating the problem.
It is an object of the invention to provide a way of improving the efficiency of the packet based transmission of data in a network, particularly a wireless network, while not placing any substantial restriction on the number of devices that can be included in the network.
According to a first aspect of the invention, there is provided a communications network operable to effect the transmission and reception of data between devices of the network in accordance with a packet based communications protocol, the network comprising means for addressing devices in the network, the means for addressing devices comprising means for monitoring the level of communication activity between devices in the network, means for determining an address length for a device in the network in accordance with said monitored level of communication activity; and means for allocating an address to said device in said network in accordance with said determined address length.
The network preferably comprises a plurality of communications devices, each device comprising a communications controller operable to control communication of said device with at least one other device in the network, the controller being operable to allocate an address to said other device, the address being allocated a number of addressing bits in a packet of data, the controller being operable to allocate the number of addressing bits on the basis of previous communications with said other device.
Each controller preferably comprises means for monitoring frequency of communication between said device and others of said devices in said network. Each controller may comprise means for modifying an address length allocation of another device addressed by the device corresponding to said controller, on the basis of monitored frequency of communication with said other device.
Each controller is preferably operable to send, with a transmitted packet, information comprising a message to a controller of another device to perform a readdressing operation, on the basis of a change in address length for addressing between the two devices.
The message may contain information defining the address length to be used for future communication.
In another embodiment, the message may contain information defining a change in address length to be used for future communication.
One of the communications devices may comprise a central controller in communication with others of said devices, said central controller being operable to control addressing of devices in said network, and including said means for addressing devices. The central controller may comprise means for monitoring frequency of communication between said device and others of said devices in said network.
The central controller may comprise means for modifying an address length allocation of another device addressed by the device corresponding to said controller, on the basis of monitored frequency of communication with said other device.
In a preferred embodiment of the invention, the central controller is operable to send, with a transmitted packet, information comprising a message to another device to perform a readdressing operation, on the basis of a change in address length for addressing between the two devices.
In a further aspect of the invention, there is provided a receiver for use in a communications network operable to receive a packet of data transmitted by a transmitting device, and including means for extracting, from a received packet, address length information defining an allocation of said packet to addressing the transmitting device; means for identifying, on the basis of the address length information, the addressing allocation in said packet, and for extracting said addressing information; and means for determining, on the basis of communication frequency information describing usage of communication between said receiver and another device, relative to communication frequency information describing usage of communication between said receiver and another addressed device, whether addressing of said former other addressed device and said latter addressed device is in accordance with relative usage, such that devices of relatively high communication usage tend to be allocated shorter address allocations than devices of relatively low communication usage.
The receiver may comprise means for monitoring frequency of communication between said receiver and other devices in communication with said receiver.
The receiver may comprise means for generating and sending an address length allocation message operable, in use, to cause a device in receipt of said message to consider a new address length allocation for use in communication with said receiver.
The receiver may include means for determining the presence of an address length allocation message m a received packet of data and means for processing said message in accordance with the allocation of address lengths of other addressed devices.
The processing means may be operable to determine from said message information defining the address length to be used for future communication.
The processing means may be operable to determine from said message information defining a change in address length to be used for future communication.
According to a further aspect of the invention, there is provided a system communication controller for operation in a network, wherein said controller establishes and maintains communication with other communications devices, said central controller being operable to control addressing of devices in said network, and including means for extracting, from a received packet, address length information defining an allocation of said packet to addressing the transmitting device; means for identifying, on the basis of the address length information, the addressing allocation in said packet, and for extracting said addressing information; and means for determining, on the basis of communication frequency information descnbng usage of communication between said receiver and another device, relative to communication frequency information describing usage of communication between said receiver and another addressed device, whether addressing of said former other addressed device and said latter addressed device is in accordance with relative usage, such that devices of relatively high communication usage tend to be allocated shorter address allocations than devices of relatively low communication usage.
According to a further aspect of the invention, a transmitter for use in a communications network comprises means for allocating addresses to devices to which the transmitter is, in use, operable to transmit a packet of data, the allocation means comprising usage monitoring means for determimng relative levels of communication with said other devices, and said allocation means being operable to allocate addresses to said devices m accordance with said relative levels of communication.
According to a further aspect of the invention, a method of addressing devices in a communications system comprises determining a usage measure for a communications link between two devices, said usage measure representing the frequency of use of said link relative to a link between one of said devices and another device, reserving a plurality of bits in a packet of data to address a device, said plurality being dependent on said usage measure, and selecting an address, of length equal to said plurality, which is distinct from other addresses for other devices of length equal to said plurality.
According to a further aspect of the invention, there is provided a method of allocating local addresses to devices in a communications network, said addresses being for use in addressing said devices in packet based data communication, each address being allocated on the basis of frequency of communication between respective devices, said method comprising the steps of monitoring the level of communication between devices in said network, determining an order of activity of devices in terms of communication with an addressing device. allocating address lengths to addressed devices in terms of said order of allocation, with shorter addresses tending to be allocated to more frequently addressed devices, and allocating distinct addresses in accordance with said address length allocation.
It will be appreciated that the invention can be embodied by a computer apparatus configured by a computer program executed thereby, to perform any of the methods of the invention, and/or to become configured as apparatus of any aspect of the invention.
Further aspects and advantages of the invention will become apparent from the following description of specific embodiments of the invention, with reference to the drawings appended hereto, in which: Figure 1 is a schematic diagram of a generic packet for transmission in a wireless communication system in accordance with an example of the prior art; Figure 2 is a schematic diagram of a physical sub-layer service data unit (PSDU) of the packet illustrated in Figure 1; Figure 3 is a illustrative example of a PSDU unit of a RTS packet in the format of the generic example given in Figure 1; Figure 4 is a specific example of a PSDU unit of a CTS packet in the format of the generic example in Figure 1; Figure 5 is a specific example of a PSDU of a data packet in accordance with the generic example given in Figure 1; Figure 6 Is a schematic diagram of a PSDU of an ACK packet in accordance with the generic example given in Figure 1; Figure 7 is a schematic illustration of a PSDU of an RTS packet in accordance with a first embodiment of the invention; Figure 8 is a schematic illustration of a PSDU of a CTS packet in accordance with the first embodiment; Figure 9 is a schematic illustration of a PSDU of a data packet in accordance with a first embodiment; Figure 10 is a schematic illustration of a PSDU of an ACK packet in accordance with the first embodiment; Figure 11 is a schematic diagram of a distributed wireless communication network in accordance with the first embodiment of the invention; Figure 12 is a schematic diagram of a communications node within the network illustrated in Figure 11; Figure 13 is a schematic diagram showing introduction of a further communications node into association with a node of the network illustrated in Figure 11; Figure 14 is a schematic diagram of a communications controller of the node illustrated in Figure 12; Figure 15 is a flow diagram illustrating a process carried out in a communications node being introduced to the network illustrated in Figure 11; Figure 16 is a flow diagram of a process carried out in a communications node to which another node is being associated in the network illustrated in Figure 11; Figure 17 is a flow diagram illustrating a process executed in the communications controller of a communications node on receipt of a packet in the wireless communications network illustrated in Figure 11; Figure 18 illustrates an address control process carried out in an address controller of the communications controller illustrated in Figure 14; Figure 19 is a flow diagram setting out a hashing function used in the allocation of addresses in the address control process illustrated in Figure 18; Figure 20 is a flow diagram illustrating a method of managing and calculating acquaintance factors in the communications controller illustrated in Figure 14; Figure 21 is a schematic diagram of a centralised wireless communications network in accordance with a second embodiment of the invention; Figure 22 is a schematic diagram of an access point of the network illustrated in Figure 21; Figure 23 is a schematic diagram of a communications controller of the access point illustrated in Figure 22; Figure 24 is a flow diagram illustrating a process executed in the access point or a communications node on receipt of a signup message from a newly introduced communications node into that network illustrated in Figure 21; Figure 25 is a schematic diagram of an address size control process executed on receipt of a packet in the network illustrated in Figure 21; Figure 26 illustrates a flow diagram setting out a process for implicit control of address size in the address management process illustrated in Figure 25; Figure 27 is an illustrated example showing the access point and one of the communications nodes in the network illustrated in Figure 21, on operation of the processes illustrated in Figures 24 to 26; Figure 28 is a further illustrated example of use of the processes illustrated in Figures 24 to 26, illustrating operation of the access point and two of the communications nodes illustrated in Figure 21; Figure 29 is a further illustrated example, similar to the example illustrated in Figure 28, involving operation of the access point and two of the communications nodes; Figure 30 is a further illustrated example, similar to the examples illustrated in Figure 28 and Figure 29, of use of the access point and two of the communications nodes, in accordance with the processes illustrated in Figures 24 to 26; and Figure 31 is a flow diagram of a process of generating a MAC address for a device, for use in the network illustrated in Figure 11 or the network illustrated in Figure 21, wherein the device previously lacked allocation of an MAC address.
Referring to Figure 11, a first embodiment of a communications system 100 in accordance with the invention is illustrated, this example being of an ad-hoc arrangement in an wireless sensor decentralised network. In such a network, conservation of energy for transmission can be an issue, and techniques promoting the conservation of such energy are advantageous. The described embodiment provides shorter addresses than the 6 byte addresses in most circumstances, thus allowing a reduction in the amount of addressing data that must be transmitted between nodes, and thus promotes energy conservation.
The system 100 comprises a plurality of communications nodes l l O (distinguished in Figure 11 by the letters A to F) each in communication with other communications nodes of the system 1 10. Each node is capable of communication with at least two other nodes 1 10, but none of the nodes 110 is capable of communication with all other nodes in the system l DO. This Is a reasonably realistic approximation to a wireless ad- hoc networking implementation such as might be encountered in a domestic or small office environment.
Each node 1 10, in accordance with the specific embodiment of the invention, manages allocation of shortened addresses in a distributed manner, to enable the nodes 1 10 to prepare and communicate packets of data without recourse to the standard 6 byte addresses with their associated overhead as described above. This enables the addressing of nodes I 10 in the system to expend less transmission energy than with the standard 6 byte MAC addressing method.
A communications node I 10 is illustrated in further detail in Figure l 2. The communications node 110 as illustrated comprises a general purpose computing device, such as a hand held computer with integrated display and user input means (keyboard, pointing device etc. Tn. detail, therefore, the communications node l l O comprises a processor 120 operable to execute machine executable instructions which can be organised into programs. these programs can be stored either in a mass storage unit 122 or a working memory l 24 in communication with the processor. In the illustrated example in Figure 12, a series of user applications 126 and a communications controller 128 are illustrated, stored in the It will be appreciated that, firstly, further programs, other than those illustrated in Figure 12, may be stored in working memory 124 to enable operation of the communications node, such as an operating system or other programs designed to configure the performance of background tasks. Secondly, all or a portion of the instructions comprising the user applications 126 and the communications controller 128 can be stored, from time to time, in the mass storage unit 122, depending on the capacity of the working memory and the extent to which rapid access is required by the processor 120.
Normally, a working memory provides rapid access but may be limited in capacity, while a mass storage unit (such as a magnetic disk drive) provides substantial storage capacity, but can only offer limited data access speed.
By means of a general purpose bus 130, the processor is in communication with a communications unit 132 connected to an antenna l 34, providing the physical means by which wireless communication can be affected by the communications node 110 with other devices. In this example, the communications unit 132 is operable to provide the physical components to establish wireless communication in accordance with the IEEE 802. l l a standard.
A user input unit 136 provides means for receiving user input actions, in the operation of the communications node. In this example, the user input unit comprises a keyboard and an imbedded pointing device, integrated into the communications node. A user output unit 138, comprising in this example a display, is capable of presenting to a user information in connection with the operation of the communications node.
In use, the communications node 110 presents facilities to a user in a generally conventional manner, allowing a user to take advantage of the facilities offered by the communications node 110 configured by the user applications 126, including effecting communication with other devices through use of the communications controller 128 configuring operation of the communication unit 132 and the sending of signals through the antenna 134. The communications node 110 is, however, in variance to conventional communications nodes in that it provides a facility for shortened addresses to be used to identify it, and similarly configured nodes 110 with which it communicates.
Initial use of the communications node, on introduction of the communications node to the system 100, involves the communications controller 128 sending a sign-up signal to neighbouring nodes l l O. for these neighbouring nodes l l O to provide the communications node l l O with a shortened address, which will be used in future communication in preference to the standard 6 byte length MAC address. This standard 6-byte MAC address may have been assigned to the communications node l 10 as a factory setting but, as will be described in due course, the present embodiment of the invention also provides a facility to enable a shortened address to be assigned in the event that the node 110 has not been pre-assigned with a MAC address for instance as a factory setting.
In accordance with this example of the invention, the shortened addresses are managed such that the shortest addresses are generally assigned to those devices which are used the most in the system, whereas address length can be greater for devices which are used infrequently.
Operation of the system of the first embodiment as illustrated in Figures l l and 12 will now be described by way of specific examples.
In figure 13, two of the communications nodes l 10 are illustrated by way of example in a portion of the network 100. The communications nodes are operable in accordance with processes of the first embodiment of the invention. It will be understood that further embodiments of the operative processes are possible, and examples of these will be described in due course.
Figure 14 illustrates the communications controller 128 of one of the nodes 1 10 (the other node corresponding). The communications controller 128 comprises an association packet handler 140 operable to generate a sign-up message to be sent to neighbouring nodes 110 during an association phase of operation of the node 110 and to handle and process association messages sent in response, and a sign-up message handler 142 operable to receive and process sign-up messages received from other communications nodes 110.
An address size controller 144 operates in use to generate address control messages to be attached to packets to be sent to neighbouring nodes, andto process corresponding address control messages sent by other communications nodes 110 from time to time.
An acquaintance factor look up table 146 stores information relating to the relative frequency of use of links with neighbouring nodes, on the basis of which information the sign-up packet handler l 40, the association packet handler 142, and the address size controller 144 operate.
Returning to figure 13, the illustrated portion of the network shows a new node G introduced into the vicinity of existing node F of the network 100 illustrated in figure 11. The node G then initiates a sign-up process, which can be for instance initiated by user input action placing a request that the device embodying the node 110 sends out a sign-up message to any neghbouring nodes 110.
The sign-up process is executed in the association packet handler 142 of the communications controller 128 illustrated in figure 14. The sign-up process in accordance with this first embodiment is illustrated in figure 15. The process of Figure is initiated on the device sensing activity from nearby nodes, and therefore deciding and attempting to sign-up to this network.
The whole process of figure 15 is usually automatic and without user intervention: A device normally is on IDLE mode, sensing the physical medium for activity. If it senses any activity, then the process of figure 15 is initiated.
Firstly, in step S1-2, a sign-up message is sent out by node G containing the full length (6-byte MAC) address of the sending node G 1 10, and a suggested starting address size.
Then, the process enters a wait mode in step S 1-4, waiting for a response from one or more neighbouring nodes 110 within a predetermined time limit.
If the time period allowed for responses is exceeded, then the process responds to this by re-entermg the idle state in step S 1-6, and then the process ends. Otherwise, on receipt of one or more association messages from neighbouring nodes (such as, in this example, node F), then in step S 1-8 these association messages are processed by storing in the acquaintance factor look up table 146 information relating to the neighbouring nodes which are the sources of these messages, including shortened address lengths, shortened addresses, and space for storing the relative frequency with which links with these neighbouring nodes are used.
Then, again on expiry of the time period within which association messages can be expected to have been received from the sending of the sign-up message, the process terminates.
A corresponding process in accordance with the first embodiment for the association of a device as a communications node 1 10 in the system will now be described with reference to figuec 16. This process, performed in any device receiving a sign-up message, and in this example node F illustrated in figure 13, results in the sending back of an association message to the originator node G (the device executing the process illustrated in figure 15). The association message is then processed in step S 1-8 as described above.
The process is executed in the sign-up packet handler 140 of node F. and is commenced on receipt of such a packet. The process commences in step S2-2 by decoding the sign- up packet, and then in step S2-4 extracting the suggested shortened address size specified in the packet by the new device to by associated as a node. This suggested shortened address size is stored in the acquaintance factor look up table as the initial value of the acquaintance factor to be used to determine a shortened address to be used by the present node in addressing the node the source of the sign-up packet, and also to determine a shortened address to identify itself to the newly signed up node 110.
In step S2-6, the process refers to the look-up table 146 to determine if any shortened addresses of the suggested length remain available for use in assigning a shortened address to the newly associated node G and the present node F executing the process. If there is a conflict, such that no unique address of the suggested length for this specific node can be allocated, then in step S2-S, the suggested address size for the newly assigned node G and for the address that the newly assigned node G will use to address the present node F. is increased. In the presently described case, the process then retunns to consider, in step S2-6 whether a conflict still remains. When a unique shortened address for node G is found, the look-up table 146 is amended accordingly.
This constitutes an alteration in the acquaintance factor, in that other devices (namely nodes A to F) already associated in the system are to take priority. Later management of the acquaintance factors represented by the address lengths associated with the devices in the network may cause re-ordering of the devices listed in the look-up table 146, which may result in the newly associated device G acquiring a lower address size and consequently shorter addressing by and of other devices in the network. This would clearly depend on the level of usage of links to the newly associated device G in the network, relative to other devices.
If finally no conflict exists, on execution of step S2-6, then in step S210 the node 110 sends an association message to the other device, containing the suggested shortened addresses (source and destination) to be used in future communication between the nodes 110 until further amendment. The process then ends.
The communications controller 128 in a node 110 operates in use, after association of the node with one or more other nodes in the network 100 to manage the receiving and sending of packets of data, where a packet is in the form of one of the packet structures illustrated in figures 7 to 10.
In particular, figure 17 illustrates a process executed in the communications controller on receipt of a packet. The process is concerned with identifying if the packet is intended from the present node as the destination, and, if so, to make any consequent changes to the short addressing carried out on the basis of frequency of use of a particular link between two nodes.
The process starts in step S3-2 on receipt of a packet, by deciding the Duration field of the packet. The data held in this field is then stored locally for later use in setting up a pause step prior to further processing in the node. Thereafter, in step S3-4, the Address Size field is decoded, and on the basis of this, the SA and DA fields are decoded in step S3-6.
In step S3-8, the decoded SA and DA addresses are expanded using entries in the look up table 146 stored in the node, and then in step S3-10 the node 110 determines whether the expanded Destination Address corresponds with the device's own allocated full length network address, predetermined on manufacture.
If the expanded destination address and the device's address do not match, then in step S3-12 the device pauses operation (sleeps) for a period of time as specified in the Duration field, and then reverts to an idle state before receiving another packet. In this case, the procedure ends thereafter.
Otherwise, in step S3-14 the remaining parts of the packet are decoded. Then, in step S3-16 the device determines if the address control field (illustrated in any of the packet structures shown in figures 7 to 10) has been set, such that an address control process executed in the address size controller 144 should be initiated in step S3-18. Otherwise, or on initiating the address size controller, the process ends.
The process can also include training and synchronization steps, performed before the decoding steps, which are facilitated by the presence of preambles and headers specific to the system at hand. For reasons of clarity, these steps are omitted from the present description of a specific first embodiment of the invention.
On detection of a new value in the address control field, the address size controller initiates an address control process as set out in figure 18. This first embodiment of the invention provides explicit address size control, where the content of the address control field m a packet received from another device maps directly to an address length that the sending device deems appropriate for future addressing along the link. Another embodiment, to be described in due course, provides implicit address control in which changes in address size are described by particular values contained in the address size
control field of a packet.
In explicit address size control, in accordance with the present embodiment of the invention, 3 bits are allocated in the Address Control field in a packet in accordance with the packet structures illustrated in figures 7 to 10 to control the number of bits allocated to shortened addresses in the use of the shortened addressing method. These three bits allow 8 different values to be provided, of which one is reserved. This reserved value is considered impermissible in the context of this communications system, and may arise, for instance, through incorrect bit detection. Any device receiving this address control value is configured to reset to full-size addresses on the next communication attempt with the corresponding node. Another value is used to revert addressing to the full-length addressing scheme such as on occasions where greater network robustness is required (e.g. in poor wireless transmission conditions).
In the present case, the specific values assigned to the Address control field are set out
in table 1:
Table 1
Address Control | meaning O O O Reserved (not permitted) O O 1 address size = 2 bits O 1 0 address size = 4 bits O 1 1 address size = 6 bits 1 0 0 address size = 8 bits 1 0 1 address size= 16 bits 1 1 0 address size = 32 bits 1 1 1 Reset to full-size address (e.g. 48 bit) The acquaintance factor associated with a link is implicit in the selection of a particular address length. A high acquaintance factor corresponds with a low address length, and vice versa. Examples of the corresponding acquaintance factor, the number of supported nodes per address size, the size of the shortened address relative to the full length address, and the savings compared to using full (48 bit) addresses are shown in
table 2:
Table 2
Acquaintance factor SA DA #nodes SA+ DA size % Savings% size size supported size decimal binary 0 111 48 bits 48 bits 2.8x104 96 bits 100 0 1 110 32 bits 32 bits 4294967295 64 bits 66.67 33.33 2 101 16 bits 16 bits 65535 32 bits 33.33 66.67 3 100 8 bits 8 bits 255 16 bits 16.67 83.33 4 011 6 bits 6 bits 63 12 bits 12.50 87.50 010 4 bits 4 bits 15 8 bits 8.33 91.67 6 001 2 bits 2 bits 4 bits 4.17 95.83 As shown in table 2 above, three nodes with address of 2 bits and 15 nodes having an address of 4 bits are supported (per sub-network). In this arrangement, it is maintained that a stream of zeros is not a valid address, as it may arise through incorrect bit detection. This rule increases the robustness of the system.
In a first step S4-2, the relative frequencies of transmission along links of the network are checked. These relative frequencies are checked against stored "acquaintance factors". An acquaintance factor is in this example an integer number approximating the age and/or usage-frequency of a link between two participating nodes. This number is stored in every node, one for every link existing for that node. Using this factor is useful in that nodes 110 that communicate very frequently will have a higher acquaintance factor and the method of allocating shortened addresses aims to take this into account when allocating addresses, using shorter addresses when two devices address each other frequently. In step S4-4, the address size controller 144 determines whether these frequencies have changed since the last check. If so, then in step S4-6 the relative acquaintance factors stored in the look-up table 146 are revised.
A method of managing and calculating acquaintance factors will be described in due course, with reference to figure 20.
If not, or after step S4-6, then in step S4-8, the address size controller 144 determines whether the new address length for the device sending the packet, and the device processing this process, can be accommodated, having regard to all existing allocated addresses of that length. If not, then the address sizes, having regard to the relative acquaintance factors of the devices linked with the device in question, need to be revised, and this is done in step S 4-10. Then, following this revision, condonation messages are sent to affected neighbouring nodes 110 affected by revisions.
On the other hand, if the new address length can be accommodated, then in step S4-14, the new addresses are allocated and, again, the new addresses are sent to the corresponding device in step S4-12. The process then ends.
A process for determining a shortened address of a specific address length (in terms of number of bits) will now be described with reference to figure l 9. This process is called in step S4-14 described above. The process acts to apply a hash function to the input data (the full-length address and the specified address length). A hash function is a transformation that takes a variable-size value as input and outputs a value of a length specified by an input variable.
The process of Figure 19 involves a low complexity hash function based on the CRC-32 resource. CRC-32 is a resource readily available in modern communication transceivers.
The CRC-32 is the CRC check function taking an input of any size and having an output of 32 bits. Thus, in step S5-2 of the process, the CRC32 function is applied to the input address, resulting in a 32 bit intermediate value. This intermediate value is then passed to step S5-4 in which a minimal complexity LSB function then operates on the 32 bit intermediate value with reference to the desired address size. Then the process outputs, in step S5-6, a value of the desired size.
In an optional step, the input address can be concatenated by prefixing 48 zero bits that facilitate the CRC operation.
If an address size higher than 32 bits is desired, then the process can be modified to enable the 32 bits intermediate value to be concatenated by itself. For example, the 32 bit intermediate value can be concatenated with itself to form a 64 bit value, and the required number of Least Significant Bits can then be taken as the output shortened address.
Figure 20 describes a method of managing acquaintance factors. In this figure, it is assumed that acquaintance factors are updated every time an RTS packet (figure 7) is received. This is merely an example, in accordance with this described embodiment, other embodiments of this invention might provide an alternative manner of updating acquaintance factors, such as updating the acquaintance factor each time a packet arrives (e.g. any one of RTS, CTS, DATA packets) at the communications controller of figure 14. It is also possible to update the acquaintance factors of all the devices associated to the communications controller only at the time when a new device signs- up with the communications controller. In that case, the acquaintance factors for all devices are re-calculated according to the flow-diagram of figure 20.
After an RTS packet is received, in step S6-2 the communications controller retrieves the acquaintance factor either using the address size infonnation from the RTS packet or using the Look-Up table entry for the specific transmitting device. In step S6-4, the communications controller then calculates the communication delay between this and previous RTS packets with the specific device that sent the RTS packet. Given a fixed time interval (time-out interval), the number of time-out intervals elapsed is calculated (variable t). The acquaintance factor is then updated in step S6-6 by adding the value of I (because an RTS packet was received) and subtracting the value of t (because there was no communication for t time- out intervals). For example, if a device transmits an RTS packet to the communications controller soon after a previously completed RTS / CTS / DATA / ACK transaction (soon means than no time-outs occurred), the acquaintance factor is increased by one, thus the communications controller will decrease the address size in the next packet.
The updated acquaintance factor is then checked for value overflows, and fixed accordingly. To this end, in step S6-8 the updated acquaintance factor is checked that it has not be recalculated to a value below zero. If so, then the updated acquaintance factor is readjusted, in step S6-10, to zero. Then, in step S6-12 the updated acquaintance factor is checked that it has not been adjusted to a value greater than a maximum value maxa. If so, the updated acquaintance factor is readjusted, in step S614, to this maximum value maxa.
A final check for the current acquaintance factor is then performed in step S6-16 by generating a short address for the device with a length given by the acquaintance factor and checking in step S6-18 for conflicts between this shortened address and shortened addresses that are currently in use for communication with other devices. If a conflict is found, then the acquaintance factor is decreased by one in step S6-20 and the check is performed again, until a unique shortened address is finally found. Then, in step S6-22, the newly calculated and verified acquaintance factor is output for use. The process then ends.
Despite the fact that the actual savings obtained using explicit address control and shortened addressing, compared with using fixed-48 bit addresses should take account of the three bits allocated to identify the address control bits (for the case of 2 bit address size, the actual savings is 92.7% for a RTS packet and 89.5% for an ACK packet), in most circumstances, this is an insignificant overhead in comparison with the advantage of using shorter addresses than the full length 48 bit addresses.
Further, it should be borne in mind that the total number of nodes supported in the shortened addressing method if this embodiment is the sum of the number of nodes supported in each address length. Thus, many nodes can be supported without recourse to the factory set full-length addresses.
Further, each node in the system 100 can choose the desired address size according to statistical information on the frequency of the current link compared to links with other devices. In one embodiment, the node could assign a much shorter address to its most popular link than less frequently used links with other devices, which could consequently be assigned much longer addresses.
Explicit address size control requires log2N bits of overhead, where N is the number of different address sizes supported for the system.
Another advantage of using explicit Address Control with a distributed network of this example is that the network automatically and eventually adapts to spatially re-using the short addresses, thereby approaching optimality, assuming that routing is not performed solely based on MAC addresses.
A second embodiment of a communications system 200 in accordance with the invention is illustrated in figure 21, this example being of a centralised communications arrangement. The system 200 comprises a plurality of communications nodes 210 each in communication with an access point 212. The access point 212 provides central coordination for the nodes 210, and offers the facility to the nodes 210 for communication with further communications networks, for example the Internet.
The access point 212 also governs the communication information between the nodes 210 and, in accordance with the invention, provides allocation of shortened addresses to enable the nodes 210 to prepare and communicate packets of data without recourse to the standard 6 byte addresses with their associated overhead as described above.
A communications node 210 is of similar hardware construction as that illustrated in figure 12. In detail, a communications controller 228 is stored in the working memory.
This communications controller enables the device to establish communications with the access point 212.
Again, in use, the communications node 210 presents facilities to a user in a generally conventional manner, allowing a user to take advantage of the facilities offered by the communications node 210 configured by user applications, including effecting communication with other devices through use of the communications controller 228 and via the access point 212.
The access point 2] 2 will now be described in further detail with reference to Figure 22.
The access point 212 is, in this example, a general purpose computing unit, comprising a processor 240 with mass storage 242 and working memory 244. The processor 240 is operable to execute instructions, such as organised into programs, which may be stored in the working memory 244 or optionally in the mass storage 242. Amongst these programs are included a plurality of administrator applications 246, providing facilities to a user of the access point 212 (a system administrator), and a central communications controller 248 which, on execution by the processor 240, provides facilities which can be used in the conduct of communication of data in the system 200.
The processor 240 communicates, via a general purpose bus 250, with a communications unit 252 which provides the physical means for communication, via an antenna 254, with communications devices 210 in the system. As for the communications nodes, the communications unit is operable in compliance with the IEEE802.11 a standard.
A user input unit 256, which in the this example includes a keyboard and pointing device, provides physical means enabling a user to perform user input actions which will be converted into input signals in the user input unit 256, for communication to the processor 240 via the general purpose bus 250. A user output unit 258 provides physical means, in this example a display, which enable information to be output to an administrator using the access point 212, on receipt of signals, via the general purpose bus 250, from the processor 240.
In use, the central communications controller 248, on execution by the processor 240, provides facilities which enable shortened addresses to be issued to communications nodes 210 in the system 200, and to be managed while the communications nodes 210 remain in the system. The communications controller is illustrated in further detail in figure 23.
The communications controller 248 comprises a sign-up packet handler 260 operable to receive a sign-up packet from a newly introduced node to the system 200, and a short addressing controller 262 operable to monitor, manage, and occasionally reorganise shortened addressing in accordance with this embodiment of the invention. To store information necessary to the allocation and management of short addresses, an addressing information look-up table 270 is provided.
Operation of the system of the second embodiment as illustrated in Figures 21 to 23 will now be described. In particular, the execution of the communications controller 248 is illustrated in the flow diagrams of figures 24 to 26.
The flow diagram in figure 24 depicts a process executed in the sign-up packet handler 260 of the communications controller 248, on receipt of a sign-up message from a communications node 210. The process by which a sign-up message is sent is equivalent to the process illustrated in figure 15 with regard to the first embodiment.
The process commences in step S7-2 by decoding the full length source address contained in the sign-up message, and creating a corresponding entry in the look up
table 270.
Then, in step S7-4, the sign-up packet handler 260 looks up in the lookup table 270 the number of devices currently active, and on that basis an appropriate initial length of a shortened address is detennined. In step S7-6, a shortened address is calculated, in the same manner as the shortened address calculation process illustrated in figure 19. Other calculation methods exist, and alternative embodiments of this aspect of the implementation wild be described in due course.
After calculation of this shortened address, the sign-up packet handler 260 determines, in step S7-8, whether the new address conflicts with existing addresses. If so, then in step S7-10, devices with conflicting addresses are re-associated with new shortened addresses, possibly of different lengths from previous shortened addresses, and association messages are sent out accordingly. Otherwise, the appropriate association message is sent out to the newly signed up node in step S7-12 and the process ends.
Figure 25 illustrates a shortened address management process canted out by the addressing controller 262 of the access point 212 on receipt of a message from a signed- up node 210 of the network. The process is concerned with managing the shortened addresses assigned to devices 210 in the network 200, with regard to the relative frequency of use of devices in the network 200.
In a first step S8-2, the relative frequencies of transmission along links of the network are checked. These relative frequencies are checked against stored "acquaintance factors". One method of managing these acquaintance factors is described above, with reference to the first embodiment, and this method can be implemented in connection with this embodiment too.
In step S8-4, the access point 212 checks whether these frequencies have changed since the last check. If not, then the process ends without revision of the address lengths of shortened addresses in the system.
However, if the frequencies are found, in step S8-4, to have changed since the last check, then in step S8-6, the address sizes of the assigned shortened addresses are revised to take account of the revised frequencies of transmission. That is, if a device is moved in the acquaintance factor rankings from a position where it should be allocated an address size of 4 bits, to an address size of 3 bits, then reassignment of this address size is carried out. A description of the method by which this is performed in accordance with this specific embodiment will follow in due course, with reference to figure 26.
Then in step S8-8, the shortened addresses, in accordance with the revised address sizes, are reassigned to the devices in the network, and in step S8-10, address assignment messages are sent to those devices which have had their shortened addresses reassigned.
The process then ends.
During communication, the addressing of a node by another in the system is maintained by the addressing controller on receipt of addressing control messages held in the
addressing size control field of a packet of data.
As described above, with regard to the first embodiment, the address size control can be carried out explicitly; this second embodiment demonstrates implicit address size control. Figure 26 illustrates a process for implicit control of address size by the access point 212 in communication with one or more communications nodes 210. It can also be performed in a communications node 210 in receipt of a message from the access point 2 12.
In the process illustrated in figure 26, address size is dropped down in steps without the need to explicitly define Address Size in the Address Control field. Instead, the Address Control provides a value that is mapped at the recipient unit (whether the Access point 212 or a communications node 210) to a message which is then processed in accordance with the method illustrated in figure 26. The set of messages (the instruction set) associated with the address control field is of a number dependent on the number of bits allocated to the Address Control field.
In this example, an instruction set associated with a 2-bit address control field comprises four possible Address Control messages:
Table 3
Address Control Bits Meaning O O Keep current address size O 1 Decrease address size 1 0 Increase address size Reset to full-size address (e.g. 48bit) The first, third and fourth messages can be followed without further enquiry, as they should result in no conflicts with other network conditions. However, the message to reduce the address size for addressing between the two devices should be assessed against other network conditions of which the device sending the message may not be aware. The two device arrangement illustrated in figure 27, a trivial example involving the access point 212 and an exemplary one of the communications nodes 210, shows how the process operates in practice. In figure 27, messages are sent in the order illustrated from top to bottom, and the process depicted by the flow diagram of figure will be described in the context ofthese messages.
The access control process commences, in step S9-2, by decoding the address control bits of a received packet. From this, it will be apparent what the source node sending the packet intends that the receiving node should do to the address size currently in use.
Then in step S9-4, the suggested address size (according to the Address Size Control bits and the current address size in use) is calculated.
In step S9-6 the address size controller 262 looks up in the look-up table 270 for the list of devices already addressed, with addresses the same length as the present address should the message represented in the address control bits be applied.
Then, with regard to this list of devices, the controller 262 then determines in step S9-8 whether an address of the suggested length can be accommodated.
If the address can be accommodated then, in step S9-10, the appropriate responding address control message is returned to the sending device on the next occasion that a packet is sent to that device, which then proceeds to calculate addresses of the appropriate length. Otherwise, in step S9-12, the current address size is retained and a corresponding message is sent to the other device by setting the Address Control bits to the binary value 00 (thereby rejecting the suggestion and ensuring that the address sizes will not decrease further). The procedure then ends.
Figure 27 illustrates a part of the network 200 including the access point 212 and a communications node 210. In the illustrated example, the access point 212 and the communications node 210 start with the usual long addresses but scale their addresses down during each packet exchange (as their acquaintance factor increases), until they reach a minimum value as specified by either of the two devices. This is achieved by performing the access control process of figure 26 each time a packet is received.
As illustrated in Figure 27, a general example of a two node system is demonstrated in which the address size is iteratively reduced in steps, finally achieving a minimum. A first RTS packet is sent by the access point 112, addressing the communications node 210 using a maximum 48-bit address size. The address control bits of the RTS packet comprise the address reduction message, and so the CTS packet sent by the communications node 210 back to the access point 212 addresses the access point 212 using a reduced address size. The CTS packet also comprises an address reduction message. This process continues sequentially until the access point 212 sends a packet to the communications node 210 which addresses the communications node using a minimum address size. At this point and onwards, the access control bits correspond with a "Keep Current Address Size" message.
In a two node case, clearly 2 bits are sufficient to address both devices. However, the minimum size is governed by the knowledge by each device of the current network status, i.e. the number of neighbouring nodes and their acquaintance factors (address sizes). Thus, where two devices do not communicate with each other frequently, they may have relatively low acquaintance factors and thus a minimum address size may be higher than 2.
The acquaintance factor is increased (and thus the address size is decreased) from packet to packet, thereby reinforcing the requirement for further reduction in the address size. Thus, when another device is introduced into the network, the high acquaintance factor between the two existing devices will initially govern the relative address sizes of the now three devices in the network. Over time, however, it may become the case that the newly introduced device will gain an acquaintance factor with the access point 212 which is higher than that of the other device, thus leading to a reassessment of the appropriate address lengths and shortened addresses. This may mean that the address length for the existing communications node 210 illustrated in figure 27 may need to be increased, and the shortened address thus will need to be reallocated.
It will be recognised that the structures of the RTS, CTS, DATA and ACK packets used in the process described herein with reference to figure 27, and in respect of subsequent examples of operation of the described embodiment of the invention, are as illustrated in figures 7 to 10 respectively.
Figures 28 to 30 illustrate operation of the second embodiment of the invention with more than two nodes to resolve a "hidden terminal short addressing problem. Referring to the figuecs, only the access point 212 has knowledge of the presence of both communications nodes 210. That is, the communications nodes 210 are not aware of each others' presence. Hence, both communications nodes 210 will try to decrease the address sizes to the minimum size and would eventually use a 2 bit address which would create collisions. For example, communications node 210 would use binary address 01 as Source Address and the other communications node 210 would inevitably generate the same address (O]) - the access point 212 would thus not have unique dentiEcation of the source of a packet. This problem is resolved by the access point 212 attempting to maintain a minimum address size that ensures no MAC address collisions, e.g. 4 bits in the example.
It will be appreciated that, because of the design of the shortened address calculation methods proposed in this invention, any node can and should calculate any short address (i.e. of any size) of all the associating nodes/devices and therefore predict all possible collisions of shortened MAC addresses. This is the reason why the nodes can avoid MAC address collisions.
In one embodiment of the invention, a device, before making a suggestion for reducing the address size, should follow the process of figure 26 to ensure that the suggestion (if accepted by the other device) will not produce a MAC address collision with other devices associated with it. In other words, the process figure 26 is followed by the transmitting device and works on the packet to be transmitted by this device (thereby simulating the process performed by the other device), ensuring that any suggestions for a new address size will not cause any conflicts with the transmitting devices associations.
In another embodiment of the invention it could be advantageous to restrict address size changes to CTS and DATA packets only. This is because the decrease in address size might otherwise be very quick and result in MAC address collisions in the case of hidden terminals. As an example (figure 29), the access point 212 uses 2 bit addresses to communicate with the right hand communications node 210. However, when the left hand communications node enters the network 200 and associates with the access point 212, the address size used quickly drops down to 2 bits, which causes a collision of MAC addresses and the access point 212 cannot identify the actual sender of the CTS packet.
Another aspect of this invention is the additional feature of supporting unnumbered devices. Currently, all network equipment have a unique MAC address which is globally unique. Allocating a unique MAC address into every device increases manufacturing costs and is a complex process. Therefore this invention solves the need for MAC address generation using the following methods: Figure 31 illustrates a method to generate MAC addresses for unnumbered devices.
Devices which have not been allocated MAC addresses would otherwise be difficult to allocate to the shortened address process illustrated and described above, because it would be difficult to accommodate them in the] ookup tables required for the performance of the specific embodiments of the invention. The process 300 takes as an input any known nodes MAC address (for instance the node which is performing the association function). Further, the process takes a 48 bit random number 304, which should preferably not be a hard wired factory value. The random number 304 is subjected to an XOR function with an initial value 306, which in this example is a 6 byte value wherein all 6 bytes have the initial value 36 (hexadecimal). In Step S10-2, the selected nodes MAC address 302 is concatenated with the result of this XOR function, and the concatenated 96 bit number is then hashed, in Step S10-4, with a 48 bit hashing function to produce a 48 bit intermediate value 314.
Then, the random number 304 is further operated with an XOR function with a second initial value 310, in this example the second initial value 310 being a 6 byte number, each byte being of value 5c (hexadecimal). In Step S 10-6, the intermediate value 314 is concatenated with this second XOR result, and in Step S 10-8, this resultant 96 bit number is hashed with a 48 bit hashing function to produce a resultant MAC address 316 for the previously unnumbered device.
An alternative approach to the generation of an MAC address for an unnumbered device is to take any existing nodes known MAC address (for instance the present node), together with a random number of the same length (in this example 48 bits), to concatenate these numbers directly and to hash this concatenated 96 bit number with a 48 bit hashing function, this hashing function resulting in a 48 bit MAC address.
implementation of this invention relies on the existence of appropriate hash functions, of which one has been described above. Further and alternative hashing functions can also be used, for example a minimal complexity LSB (Least Significant bits) function acting as a hash function without scrambling of the input of any sort. The desired number of least significant bits are taken from the input and act as an output to the function.
This invention provides a method and apparatus for implementing scalability of the size of addresses used in the identification of devices in a network, to accommodate networks of any size, at reduced complexity. The invention allows addressing to be adaptable to any number of associated terminals without any centralised control or distributed algorithm (involving control packet exchanges). It also provides a predetermined number of available address sizes, thus ensuring that the address length can be encoded into a smaller number of bits than if the address length had to be described directly.
Clearly, in the general case, the number of bits allocated for Address Control will depend on the number of different address sizes supported in the system. The specific address-sizes supported also depends on the system. It should however be noted that address sizes should be chosen in order to facilitate low-complexity design for the devices. In another embodiment, address sizes could include multiples of 8 bits (or perhaps 4 bits) that would facilitate byte (or half-byte) processing in both the transmitting and receiving sides. The number indicating the difference in size (in bits) between the addresses is termed as base unit in this invention. The base unit would be dependent on the device's hardware architectures, so for example, a communications system deploying wireless sensor devices based on 4-bit microcontrollers would opt for 4 bits as a base unit, so it would support address sizes chosen from: {4, 8, 12, 16, 20, 24 etc.} bits.
It will be appreciated that other devices, enabled for wireless communication, could equally be used in place of this described communications node, with suitable adaptations. For example, a general purpose computer may be configured for use as a communications node by means of the introduction and execution of one or more suitable software products, while an alternative embodiment could be provided which was initially configured, such as through the use of application specific integrated circuits (ASICs) to perform the same processes to deliver the same communications facilities.
It will be appreciated that the invention is not restricted to wireless communication in accordance with the IEEE802. 1 1 a standard. Implementations of the invention in accordance with other communications standards are also possible.

Claims (52)

  1. CLAIMS: 1. A communications network operable to effect the transmission
    and reception of data between devices of the network in accordance with a packet based communications protocol, the network comprising means for addressing devices in the network, the means for addressing devices comprising: means for monitoring the level of communication activity between devices in the network; means for determining an address length for a device in the network in accordance with said momtored level of communication activity; and means for allocating an address to said device in said network in accordance with said determined address length.
  2. 2. A network in accordance with claim 1, comprising a plurality of communications devices, each device comprising a communications controller operable to control communication of said device with at least one other device in the network, the controller being operable to allocate an address to said other device, the address being allocated a number of addressing bits in a packet of data, the controller being operable to allocate the number of addressing bits on the basis of previous communications with said other device.
  3. 3. A network in accordance with claim 2 wherein each controller comprises means for monitoring frequency of communication between said device and others of said devices in said network.
  4. 4. A network in accordance with claim 3 wherein each controller comprises means for modifying an address length allocation of another device addressed by the device corresponding to said controller, on the basis of monitored frequency of communication with said other device.
  5. 5. A network in accordance with any of claims 2 to 4 and wherein each controller is operable to send, with a transmitted packet, information comprising a message to a controller of another device to perform a readdressing operation, on the basis of a change in address length for addressing between the two devices.
  6. 6. A network in accordance with claim 5 wherein the message contains information defining the address length to be used for future communication.
  7. 7. A network in accordance with claim 5 wherein the message contains information defining a change in address length to be used for future communication.
  8. 8. A network in accordance with claim 1 and wherein one of said communications device comprises a central controller in communication with others of said devices, said central controller being operable to control addressing of devices in said network, and including said means for addressing devices.
  9. 9. A network in accordance with claim 8 wherein the central controller comprises means for monitoring frequency of communication between said device and others of said devices in said network.
  10. 10. A network in accordance with claim 9 wherein the central controller comprises means for modifying an address length allocation of another device addressed by the device corresponding to said controller, on the basis of monitored frequency of communication with said other device.
  11. 11. A network in accordance with any of claims 8 to O and wherein the central controller is operable to send, with a transmitted packet, information comprising a message to another device to perform a readdressing operation, on the basis of a change in address length for addressing between the two devices.
  12. 12. A network in accordance with claim 11 wherein the message contains information defining the address length to be used for future commumcation.
  13. 13. A network in accordance with claim 11 wherein the message contains information defining a change in address length to be used for future communication.
  14. 14. A receiver for use in a communications network operable to receive a packet of data transmitted by a transmitting device, and including: means for extracting, from a received packet, address length information defining an allocation of said packet to addressing the transmitting device; means for identifying, on the basis of the address length information, the addressing allocation in said packet, and for extracting said addressing information; and means for determining, on the basis of commumcation frequency information describing usage of communication between said receiver and another device, relative to communication frequency information describing usage of communication between said receiver and another addressed device, whether addressing of said former other addressed device and said latter addressed device is in accordance with relative usage, such that devices of relatively high communication usage tend to be allocated shorter address allocations than devices of relatively low communication usage.
  15. 15. A receiver in accordance with claim 14 comprises means for monitoring frequency of communication between said receiver and other devices in communication with said receiver.
  16. 16. A receiver in accordance with claim 15 comprising means for generating and sending an address length allocation message operable, in use, to cause a device in receipt of said message to consider a new address length allocation for use in communication with said receiver.
  17. 17. A receiver in accordance with claim 16 and including means for determining the presence of an address length allocation message in a received packet of data and means for processing said message in accordance with the allocation of address lengths of other addressed devices.
  18. 18. A receiver in accordance with claim 17 and wherein the processing means is operable to determine from said message information defining the address length to be used for future communication.
  19. l 9. A receiver in accordance with claim 17 and wherein the processing means is operable to determine from said message information defining a change in address length to be used for future communication.
  20. 20. A system communication controller for operation in a network, wherein said controller establishes and maintains communication with other communications devices devices, said central controller being operable to control addressing of devices in said network, and including means for extracting, from a received packet, address length information defining an allocation of said packet to addressing the transmitting device; means for identifying, on the basis of the address length information, the addressing allocation in said packet, and for extracting said addressing information; and means for determining, on the basis of communication frequency information describing usage of communication between said receiver and another device, relative to communication frequency information describing usage of communication between said receiver and another addressed device, whether addressing of said former other addressed device and said latter addressed device is in accordance with relative usage, such that devices of relatively high communication usage tend to be allocated shorter address allocations than devices of relatively low communication usage.
  21. 21. A controller in accordance with claim 20 and comprising means for monitoring frequency of communication between said device and others of said devices in said network.
  22. 22. A controller in accordance with claim 21 comprising means for modifying an address length allocation of another device addressed by said controller, on the basis of monitored frequency of communication with said other device.
  23. 23. A controller in accordance with any of claims 20 to 22 and wherein the central controller is operable to send, with a transmitted packet, information comprising a message to another device to perform a readdressing operation, on the basis of a change in address length for addressing between the two devices.
  24. 24. A controller in accordance with claim 23 wherein the message contains information defining the address length to be used for future communication.
  25. 25. A controller in accordance with claim 23 wherein the message contains information defining a change in address length to be used for future communication.
  26. 26. A transmitter for use in a communications network comprising means for allocating addresses to devices to which the transmitter is, in use, operable to transmit a packet of data, the allocation means comprising usage monitoring means for determining relative levels of communication with said other devices, and said allocation means being operable to allocate addresses to said devices in accordance with said relative levels of communication.
  27. 27. A transmitter in accordance with claim 26 and operable to receive a message from another device in said network, information comprising a message to perform a readdressing operation, on the basis of a change in address length for addressing between the two devices.
  28. 28. A transmitter in accordance with claim 27 wherein the message contains information defining the address length to be used for future communication.
  29. 29. A transmitter in accordance with claim 27 wherein the message contains information defining a change in address length to be used for future communication.
  30. 30. A method of addressing devices in a communications system comprising determining a usage measure for a communications link between two devices, said usage measure representing the frequency of use of said link relative to a link between one of said devices and another device, reserving a plurality of bits in a packet of data to address a device, said plurality being dependent on said usage measure, and selecting an address, of length equal to said plurality, which is distinct from other addresses for other devices of length equal to said plurality.
  31. 31. A method in accordance with claim 30, the method comprising allocating an address to said other device, the address being allocated a number of addressing bits in a packet of data, including allocating the number of addressing bits on the basis of previous communications with said other device.
  32. 32. A method in accordance with claim 31 including monitoring frequency of communication between said device and others of said devices in said network.
  33. 33. A method in accordance with claim 32 including modifying an address length allocation of another device addressed by the device corresponding to said controller, on the basis of monitored frequency of communication with said other device.
  34. 34. A method in accordance with any of claims 31 to 33 and including sending, with a transmitted packet, information comprising a message to a controller of another device to perform a readdressing operation, on the basis of a change in address length for addressing between the two devices.
  35. 35. A method in accordance with claim 34 wherein the message contains information defining the address length to be used for future communication.
  36. 36. A method in accordance with claim 34 wherein the message contains information defining a change in address length to be used for future communication.
  37. 37 A method in accordance with claim 30 in a central controller in communication with other communications devices in a network.
  38. 38. A method in accordance with claim 37 comprising monitoring frequency of communication between said central controller and others of said devices in said network.
  39. 39. A method in accordance with claim 38 comprising modifying an address length allocation of another device addressed by the device corresponding to said controller, on the basis of monitored frequency of communication with said other device.
  40. 40. A method in accordance with any of claims 37 to 39 and comprising sending, with a transmitted packet, information comprising a message to another device to perform a readdressing operation, on the basis of a change in address length for addressing between the two devices.
  41. 41. A method in accordance with claim 40 wherein the message contains information defining the address length to be used for future communication.
  42. 42. A method in accordance with claim 40 wherein the message contains information deeming a change in address length to be used for future communication.
  43. 43. A method of allocating local addresses to devices in a communications network, said addresses being for use in addressing said devices in packet based data communication, each address being allocated on the basis of frequency of communication between respective devices, said method comprising the steps of monitoring the level of communication between devices in said network, determining an order of activity of devices in terms of communication with an addressing device.
    allocating address lengths to addressed devices in terms of said order of allocation, with shorter addresses tending to be allocated to more frequently addressed devices, and allocating distinct addresses in accordance with said address length allocation.
  44. 44. A method of allocating local addresses in accordance with claim 43, including the step of reviewing the allocation of addresses from time to time.
  45. 45. A method of allocating local addresses in accordance with claim 43 or claim 44, including the step of reviewing the order of activity of devices from time to time.
  46. 46. A method of allocating local addresses in accordance with any of claims 43 to 45, and including the step of communicating with the addressed device the length of the address to be used in future communication between the two devices.
  47. 47. A method of allocating local addresses in accordance with claim 46 wherein the step of communicating comprises sending a message indicating the length of the address.
  48. 48. A method of allocating local addresses in accordance with claim 46 wherein the step of communicating comprises sending a message indicating a change in the length of the address to be used in future communication.
  49. 49. A method in accordance with any of claims 43 to 48 including the step of allocating a predetermined number of address length indicator bits in a packet of data for indicating the length of the address or addresses contained in said packet of data.
  50. 50. A computer readable storage device carrying computer program instructions capable of configuring a computer as a communications device operable in the network according to any of claims I to 13, as a receiver in accordance with any of claims 14 to 19, as a controller in accordance with any of claims 20 to 25, or as a transmitter in accordance with any of claims 26 to 29.
  51. 51. A signal receivable by a computer, the signal carrying computer program instructions capable of configuring a computer as a communications device operable in the network according to any of claims 1 to 13, as a receiver in accordance with any of claims 14 to 19, as a controller in accordance with any of claims 20 to 25, or as a transmitter in accordance with any of claims 26 to 29..
  52. 52. A signal receivable by a computer, the signal carrying computer program Qtrticti(li cctptllc' :''- c',,tI"t,, Ala'' ?. co.1ll,Ite to! c! !--, : ':etIcl: a] accordance with any of claim, 29 to 48, or capable of configuring a computer to perform a methyl, alongside correspondingly configured computers, such that said configured computers collectively perform a method in accordance with any of claims 29 to 48.
    52. A computer readable storage device carrying computer program instructions capable of configuring a computer to perform a method in accordance with any of claims 30 to 49, or capable of configuring a computer to perform a method, alongside correspondingly configured computers, such that said configured computers collectively perform a method in accordance with any of claims 30 to 49.
    53. A signal receivable by a computer, the signal carrying computer program instructions capable of configuring a computer to perform a method in accordance with any of claims 30 to 49, or capable of configuring a computer to perform a method, alongside correspondingly configured computers, such that said configured computers collectively perform a method in accordance with any of claims 30 to 49.
    Amendments to the claims have been filed as follows CLAIMS: I A commumcatons network operable to cEfect the transmission and reception of data between devccs of the network in accordance with a packet based communications protocol, the network comprising means for addressing devices in the network, the means for addressing devices composing: means for monitoring the level of communication activity between devices in the network; means for determining an address length for a device in the network in accordance with said monitored level of communication activity; and means for allocating an address to said device in said network in accordance with said determined address length.
    2. A network in accordance with claim 1, comprising a plurality of communications devices, each device comprising a communications controller operable to control comTnunTcation of said device with at least one otl-ler device in the network, the controller being operable to allocate an address to said other device, the address being allocated a number of addressing bits not a packet of data, the controller bemg operable to allocate the number of addressing bits on the basis of previous communications with said other device.
    3. A network Tm accordance with clang 2 wheT-en each controller comprises means for monit:orTng frequency of commuTlicatTon between said device and others of said devices in said network.
    4 network u., accordance with claTTT1 3 wherein each controller comprises means for modfymg an address length allocation of another device addressed by the device corresponding to said controller on the basis of monitored frequency of communication with said other device.
    5. network in accordaTlce WTt}1 any of clangs 2 to 4 and wherein each controller is opeT-able to send, with a transmitted packet, nfonnaton compnsng a message to a controller of another device to perform a readdressing operation, on the basis of a change in address length for addressing between the two devices 6. A network In accordance with claim 5 whcrem the message contains information defining the address length to be used for future communication 7. A nctvtork in accordance with claim 5 wherein the message contains information definmg a change In address length to be used for future communication.
    S. A network in accordance with claim 1 and wherein one of said communications device comprises a central controller In communication with others of said devices, said central controller being operable to control addressing of devices in said network, and including said means for addressing devices.
    9. A network in accordance with claim 8 wherein the central controller comprises means for:nonitoring frequency of communication between said device and others of said devices in said network.
    10. A network in accordance with claim 9 wherein the central controller comprises means for modifying an address length allocation of another device addressed by the device corresponding to said controller, on the basis of monitored frequency of COrnmuniCatiGn with said othei- device ] 1. A network in accordance with any of claims to 10 and wherein the central controller is operable to send, with a transmitted packet, information comprising a message to another device to perform a readdressing operation, on the hasps of a charge in address length for addressing between the two devices.
    12. A networl; In accordance with claim 11 wherein the message contains information defining the address length to be used for future communication 13. A network in accordance with claim 1] whereat the message contanls fc> ,-ia;.i ii,,.iii pi.l,:iie,, ,,c, i s; !f'i!,i f] [:] by' 'IS. i.)r t'lilure co:l.:unr..+ic> 14. A receiver for use In a communications network operable to receive a packet of data transmitted by a transmitting device, and including: means for extracting, from a received packet, address length information defining an allocation of said packet to addressing the transmitting device; means for Identifying, Oil the basis of the address length information. the addressing allocation in said packet, and for extracting said addressing information; and means for dcterrmning, on the basis of communication frequency information descnbng usage of communication bctwocn said receiver and another device, relative to communication frequency information describing usage of communication between said receiver and another addressed device, whether addressing of said former other addressed device and said latter addressed device is in accordance with relative usage, such that devices of relatively high communication usage tend to be allocated shorter address allocations than devices of relatively low communication usage.
    15. A receiver al accordance with claim 14 comprises means for monitoring frequency of communication between said receiver and other devices in communication with said receiver.
    16. A receiver in accordance with claim 15 comprising means for generating and sending an address length allocation message operable, in use, to cause a device m receipt of said message to consider a new address length allocation for use in communication with said receiver.
    17. A receiver in accordance with claim 16 and including means for determining the presence of an address length allocation message in a received packet of data and means for processing said message in accordance with the allocation of address lengths of other addressed dcvces 18. A receiver m accordance with claim 17 and wherem the processing means is operable to detennme from said message mfomlaton definmg the address length to be used for fire comm:tncaton 19. A receiver in accordance with claim 17 and wherein the processing means is operable to determine from said message information deLimng a change in address length to be used for future communication.
    20. A system communication controller for operation in a network, wherein said controller establishes and maintains communication with other communications devices devices, said central controller being operable to control addressing of devices In said network, and including means for extracting, from a received packet, address length information defining an allocation of said packet to addressing the transmitting device; means for identifying, on the basis of the address length information, the addressing allocation in said packet, and for extracting said addressing information; and means for determimng, on the basis of communication frequency information describing usage of communication between said receiver and another device, relative to communication frequency information describing usage of communication between said receiver and another addressed device, whether addressing of said former other addressed device and said latter addressed device is in accordance with relative usage, such that devices of relatively high communication usage tend to be allocated shorter address allocations than devices of relatively low communication usage.
    2] . A controller in accordance with claim 20 and comprising means for monitoring frequency of communication between said device and others of said devices in said network.
    22. A controller In accordance with claim 21 comprising means for modifying an address length allocation of another devcc addressed by said controller, on the basis of monitored frequency of communication with said other device.
    23. A controller in accordance with any of claims 20 to 22 and wherein the central controller is operable to send, with a transmitted packet, information comprising a message to another device to perform a readdressing operation, on the basis of a change In address length for addressing between the two devices.
    24 A controller in accordance with claim 23 vheTeiT1 the message contains information defining the address length to be used for future communication 25. A coTltroller its accordance with ciaiTll 23 wheTein the message contains formation defining a change m address length to be used for future comm unication 26. A transmitter for use in a comT1ltT1icatioT1s network comprising means for allocating addresses to devices to which the transmitter is, m use, operable to transmit a packet of data, the allocation ineans comprising usage monitoring means for determining relative levels of communication with said other devices, and said allocation means being operable to allocate addresses to said devices in accordance with said relative levels of communication, and further operable to receive a message to perform a readdressing operatioTl' OT1 the basis ol a change in address length for addressing between the transmitter and another device in said network 27. A transmitter in accordance with claim 26 wherein the message contains information defining tl1e address length to be used for futLTTe communication 28. A transmitter iT1 accordance with claim 26 wherein the message contains information deeming a ella.nge in address length to be used for future Communication.
    29. A method of addressing devices in a communications system comprising determining a usage measure for a communications link between two devices, said usage measure representing the frequency of use of said dint relative to a link between one of said devices and another device, reserving a plurality of bits IT1 a packet of data to address a devTee, said plurality bemg dependent on said usage measure, and seleetmg an address. of lerIgth equal to said plurality, which is distinct from other- addresses lor other devices of length equal to said plurality.
    3(). A method in accordance with claim 29, the method comprising allocating an ti31TeSS to StU(T ot;,CT.TC'n';CC. Zinc tili-cgs INCITE,I, cttctl.i i'.;TlllOCT of (1ITC j jU1, 4q bits in a pachct of data, including allocating the number of addressing hits off the basis of previous communications with said other dcvce.
    31. A method in accordance with claim 30 including monitoring frequency ol communication between said device and others of said devices in said network.
    32 A method in accordance with claim 31 including modifying an address length allocation of another device addressed by the device corresponding to said controller, on the basis ol'monitored frequency ot'communicaton with said other device.
    33. A method in accordance with any of claims 30 to 32 and including sending, with a transmitted packet, information comprising a message to a controller of another device to perform a r eaddressing operation, on the basis of a change in address length for addressing between the two devices.
    34. A method In accordance with claim 33 wherein the message contains information defining the address length to be used for future communication.
    A method in accordance with claim 33 wherein the message contains information defining a change in address length to be used for future communication.
    36. method in accordance with claim 29 in a central controller in communication with other communications devices in a network 37. A method in accordance with claim 36 comprising monitoring fiequency of communication between said central controller and others of said devices in said network.
    38. A method in accordance with claim 37 comprising modifying an address length allocation of another device addressed by the device corresponding to said controller, on the basis of monitored frequency of communication with said Other device.
    39. A method in accordance with any of claims 36 to 38 and comprising sending with a transmitted packet, information comprising a message to another device to perform a readdressing operation, on the basis of a change m address length for addressing between the two devices.
    4(). A method iT1 accordance with claim 39 wherein the message contains information defining the address length to be used for future communication.
    41. A method in accordance with claim 39 wherein the message eontams infonnation defining a change in address length to be used for future communications 42 A method of allocating local addresses to devices in a communications network, said addresses being for use in addressing said devices in packet based data communication, each address being allocated on the basis of frequency of communication between respective devices, said method comprising the steps of monitoring the level of communication between devices in said network, determining an order of activity of devices in terms of communication with an addressing device. allocating address lengths to addressed devices in terms of said order of allocation, with shorter addresses tending to be allocated to more frequentlyaddressed devices, and allocating distinct addresses in accordance with said address length allocation.
    4. A method of allocating local addresses in accordance with claim 42, including the step of reviewing the allocation of addresses front time to time.
    44. A method of allocating local addresses in accordance with claim 42 or claim 43, including the step of reviewing the order of activity of devices from time to time.
    45. A method of allocating local addresses in accordance with any of claims 42 to 44, and including the step of communicating with the addressed device the length of the address to be used in future communication between the two devices.
    46 method of allocating local addresses in accordance with claim 45 NvLerein the step of communicating comprises sending a message indicating the length of the address.
    47. A method of allocating local addresses in accordance with claim 45 wherein the step of communicating comprises sending a message indicating a change in the length ol the address robe used in future communication.
    48. A method in accordance with any of claims 42 to 47 including the step of allocating a prcdctcrmincd number of address length indicator bits in a packet of data for indicating the length of the address or addresses contained in said packet of data.
    49. A computer readable storage device carrying computer program instructions capable of configuring a computer as a communications device operable in the network according to any of claims 1 to 13, as a receiver in accordance with any of claims 14 to 19, as a controller in accordance with any of claims 20 to 25, or as a transmitter in accordance with any of claims 26 to 28.
    50. A signal receivable by a computer, the signal carrying computer program instructions capable of configuring a computer as a communications device operable in the network according to any of claims I to 13, as a receiver in accordance with any of claims 14 to 19, as a controller in accordance with any of claims 20 to 25, or as a transmitter in accordance with any of claims 26 to 28.
    51. A computer readable storage device carrying computer program instructions capal:>le of configuring a computer to perform a method in accordance with any of claims 29 to 48, or capable of configunng a computer to perform a method, alongside correspondingly configured computers, such that said configured computers collectively perform a method in accordance with any of claims 29 to 48.
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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008096254A2 (en) 2007-02-09 2008-08-14 Nokia Corporation Forbidden tracking area optimization for private/home networks
US8098662B2 (en) 2006-06-07 2012-01-17 Qualcomm Incorporated Method and apparatus for using short addresses in a communication system
EP2445239A1 (en) * 2010-10-22 2012-04-25 Research in Motion Limited Method and system for identifying an entity in a mobile telecommunications system
WO2013000711A1 (en) * 2011-06-30 2013-01-03 Siemens Aktiengesellschaft Methods and apparatuses for creating addresses for subscribers in a network
CN103209045A (en) * 2012-01-12 2013-07-17 华为终端有限公司 Data communication method, device and system
WO2015038239A1 (en) * 2013-09-10 2015-03-19 Illinois Tool Works Inc. Digital networking in a welding system
EP3094121A1 (en) * 2015-05-12 2016-11-16 Alcatel Lucent Apparatuses, methods and computer programs for providing information related to identifications of a plurality of mobile transceivers
US11165749B2 (en) * 2016-02-12 2021-11-02 Advanced Micro Devices, Inc. Assigning variable length address identifiers to packets in a processing system

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001067676A2 (en) * 2000-03-03 2001-09-13 Luminous Networks, Inc. Dual-mode virtual network addressing
US20020061757A1 (en) * 2000-11-22 2002-05-23 Hunzinger Jason F. Variable mobile address lengths for efficient mobile paging and standby

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2411317B (en) * 2004-02-20 2007-06-13 Toshiba Res Europ Ltd Network addressing scheme
GB2413037B (en) * 2004-04-07 2006-02-15 Toshiba Res Europ Ltd Network addressing

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001067676A2 (en) * 2000-03-03 2001-09-13 Luminous Networks, Inc. Dual-mode virtual network addressing
US20020061757A1 (en) * 2000-11-22 2002-05-23 Hunzinger Jason F. Variable mobile address lengths for efficient mobile paging and standby

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Distributed On-Demand Address Assignment in Wireless Sensor Networks. IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS, VOL. 13, NO. 10, OCTOBER 2002 *

Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8416751B2 (en) 2006-06-07 2013-04-09 Qualcomm Incorporated Method and apparatus used for airlink communications
US8098662B2 (en) 2006-06-07 2012-01-17 Qualcomm Incorporated Method and apparatus for using short addresses in a communication system
US8259702B2 (en) 2006-06-07 2012-09-04 Qualcomm Incorporated Efficient over the air address methods and apparatus
US8134952B2 (en) 2006-06-07 2012-03-13 Qualcomm Incorporated PN code based addressing methods and apparatus for airlink communications
WO2008096254A2 (en) 2007-02-09 2008-08-14 Nokia Corporation Forbidden tracking area optimization for private/home networks
US8116736B2 (en) 2007-02-09 2012-02-14 Nokia Corporation Forbidden tracking area optimization for private/home networks
CN101606406B (en) * 2007-02-09 2013-04-17 诺基亚公司 Forbidden tracking area optimization for private/home networks
WO2008096254A3 (en) * 2007-02-09 2008-10-30 Nokia Corp Forbidden tracking area optimization for private/home networks
EP2445239A1 (en) * 2010-10-22 2012-04-25 Research in Motion Limited Method and system for identifying an entity in a mobile telecommunications system
US10194314B2 (en) 2010-10-22 2019-01-29 Blackberry Limited Method and system for identifying an entity in a mobile device ecosystem
WO2013000711A1 (en) * 2011-06-30 2013-01-03 Siemens Aktiengesellschaft Methods and apparatuses for creating addresses for subscribers in a network
CN103209045A (en) * 2012-01-12 2013-07-17 华为终端有限公司 Data communication method, device and system
EP2793448A4 (en) * 2012-01-12 2015-03-11 Huawei Device Co Ltd Method, device, and system for data communication
CN106850140B (en) * 2012-01-12 2020-04-28 华为终端有限公司 Data communication method, device and system
CN106850140A (en) * 2012-01-12 2017-06-13 华为终端有限公司 The method of data communication, apparatus and system
CN106877977A (en) * 2012-01-12 2017-06-20 华为终端有限公司 The method of data communication, apparatus and system
US9906491B2 (en) 2012-01-12 2018-02-27 Huawei Device (Dongguan) Co., Ltd. Improving transmission efficiency of data frames by using shorter addresses in the frame header
WO2015038239A1 (en) * 2013-09-10 2015-03-19 Illinois Tool Works Inc. Digital networking in a welding system
US10270719B2 (en) 2013-09-10 2019-04-23 Illinois Tool Works Inc. Methods for handling data packets in a digital network of a welding system
US11343211B2 (en) 2013-09-10 2022-05-24 Illinois Tool Works Inc. Digital networking in a welding system
EP3094121A1 (en) * 2015-05-12 2016-11-16 Alcatel Lucent Apparatuses, methods and computer programs for providing information related to identifications of a plurality of mobile transceivers
US11165749B2 (en) * 2016-02-12 2021-11-02 Advanced Micro Devices, Inc. Assigning variable length address identifiers to packets in a processing system
US20220029954A1 (en) * 2016-02-12 2022-01-27 Advanced Micro Devices, Inc. Assigning variable length address identifiers to packets in a processing system
US11936616B2 (en) * 2016-02-12 2024-03-19 Advanced Micro Devices, Inc. Assigning variable length address identifiers to packets in a processing system

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