RU2446451C2 - Accelerated messaging method, virtual network and broadband wireless communication device using retransmission in parallel composite channels - Google Patents

Abstract

FIELD: information technology.

SUBSTANCE: method involves: determining the category of an incoming message, calculating the required virtual network resource based on analysis of parameters of the incoming message and its typical statistical characteristics, preliminary formation of the topology of the virtual network, setting up the virtual network and correcting the topology based on estimated capabilities of the broadband wireless network for the network cell formation mode for the purpose of parallel packet transmission, multichannel packet transmission over composite channels and filtration thereof in accordance with the construction principle of the virtual network, and based on formation of the virtual network and broadband wireless communication device using retransmission in parallel composite channels.

EFFECT: improved speed characteristics and reliability of networks with moderate packet network loads.

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Description

Technical field

The present invention relates to broadband wireless communications using relaying to increase the speed and reliability of message (data) transmission. In particular, the invention relates to a method, virtual network and device for a broadband wireless network with relaying, including in packet switching modes, with two or more transit sections.

State of the art

The tasks of increasing the reliability and speed of bringing information to a large extent have been solved at the channel level. However, for communication systems and networks with low-speed channels, due to the limited possibility of the data link layer, the solution of these problems lies in the network plane. This approach is relevant for almost all wireless networks due to, on the one hand, the availability of resource limitations for communication channels, and, on the other hand, to the constant growth in the volume of transmitted traffic by mobile users. In this regard, the direction of dynamic and flexible changes in the network structure under conditions of limiting information on the network topology and the replacement of single communication channels (paths) by virtual cells with the implementation of parallelism aspects in them (the essence of the method of the present invention) is important.

A well-known hierarchical communication network (patent RU No. 2265967 C2, class H04Q 11/06, 2005), which allows you to flexibly expand the network configuration without significantly increasing the power of computer technology and increase the speed of information transfer by applying the method of forming a radio network structure based on fuzzy theory subsets (Kofman A. Introduction to the theory of fuzzy sets. - M .: Radio and communications, 1982). The resulting structures are fuzzy and have a strict order, so for an unambiguous determination of the address of the transition node it is enough to indicate its identification number. The topology code is the operation of finding the Hamming distance between elements of the membership set (characteristic function) L. The properties of the elementary structure L that make up the network cell are inherited by the complex structure L ^E , where E is a universal set of arbitrary power. Thus, to construct a structure of any complexity, it is enough to specify the elementary structure L. The topology formation unit works in accordance with the algorithm (Gorev P.G., Gorazdovsky T.Ya., Pasechnikov I.I., Zhelonkin V.V. Formation of packet radio network structures of varying complexity. - M.: Radio Engineering (magazine in the journal). 2001. No. 4. S.25-30). The disadvantage of this network is the lack of a way to form network cells (virtual subnets) for implementing the mode of accelerated message transmission through parallel transmission of packets.

Closest to the proposed invention is a method and system for wireless networks using relaying (patent RU No. 2342800 C2 class. H04L 25/52, 2008), comprising a transmitter, a receiver and at least one relay station participating in communication session. The relay station sends signals from the first communication line between the transmitter and the relay station to the second communication line between the relay station and the receiver. Forwarding by at least one relay station is adapted in accordance with the estimated characteristics of the radio channel of the first and second communication lines. As a result, based on the determination and adaptation of transmission parameters for communication channels with two relay sections in a wireless communication system, it is possible to implement a mode of parallel information transmission. This invention allows you to more fully use the advantages of cooperative relaying to increase the throughput and flexibility of the system, however, it does not consider the method and devices that allow you to present a composite communication channel (based on relaying, including taking into account the parallelism aspect) in the form of a virtual network cell with coordinated packet transmission, the structure of which is determined by both the network topology and the parameters of the transmitted message.

SUMMARY OF THE INVENTION

The present invention includes an accelerated messaging method, a virtual network, and an apparatus for a broadband data network. The method of accelerated messaging combines the advantages of the above inventions, in particular, the method of forming a topology in a hierarchical communication network (patent RU No. 2265967 C2, CL H04Q 11/06, 2005), a method that adapts the transmission of information by a relay station in accordance with the assessment characteristics of the radio channels of the first and second communication lines of the relay line and, thereby, providing cooperative relaying in a network segment with two transit sections (method and system for wireless communication networks using a relay ligation (patent RU No. 2342800 C2 class. H04L 25/52, 2008)), and includes additional procedures that form virtual networks and provide an accelerated mode of transmitting messages to them.

The main objective of the method is to increase the speed of message delivery to users under conditions of limiting the throughput of communication channels by forming virtual networks in a broadband wireless network with structural redundancy for the duration of message transmission, realizing packet transmission through parallel composite channels of the formed network cell. It provides for the sequential execution of the following operations: determining the category of the input message; calculation of the required virtual network resource based on an analysis of the parameters of the input message and its typical statistical characteristics; preliminary formation of virtual network topology; virtual network setup and topology correction based on the estimated capabilities of a broadband wireless network for the formation mode of a virtual network (network cell) for the purpose of parallel transmission of packets; multichannel transmission of packets over composite channels and their filtering in accordance with the principle of constructing a virtual network. The method for accelerated messaging of the present invention is based on the formation of a virtual network (cell) and a device for broadband wireless communication using relay in parallel composite channels.

A virtual network with a virtual cell architecture, which is a multi-channel transmitter (group of transmitters) connected (e) by direct communication channels to a multi-channel relay node (group of relay nodes) interconnected by direct communication channels depending on the number of transit sections and on the last the area connected to the multi-channel receiver (group of receivers) is formed in accordance with the method described in the hierarchical communication network (patent RU No. 2265967 C2, class. H04Q 11/06, 2005) and in accordance with the algorithm for constructing soft structures (Gorev P.G., Gorazdovsky T.Ya., Pasechnikov I.I., Zhelonkin V.V. Formation of packet radio network structures of varying complexity. - M.: Radio engineering (journal in the journal). 2001. No. 4. P.25-30), characterized by the presence of the configuration mode for the implementation of parallel transmission of packets of the input message. Figure 1 shows an example of a network cell with two transit sections, formed to transmit message packets on eight parallel composite channels. Block 1 - a group of four transmitters, blocks 2 and 3 - diversity groups of relay nodes, block 4 - a multi-channel receiver (or a group of diversity receivers). The points (a, b), where a = 0, α, β, 1 and b = 0, α, β, 1, correspond to packet reception and transmission devices (relay stations), while the values 0, α, β, 1 characterize logical sublevels of the network cell and describe the various degrees of resource utilization of relay nodes. Such subnets will conditionally be called subnets of α _i -levels. The transition from level to level of the network cell structure in the combined groups is possible when implementing the method of statistical channel multiplexing in the system or based on the conditions of packet transmission over the network.

A device for a broadband wireless network (figure 2) using relaying in parallel composite channels consists of: a transmitting part (12), characterized by the presence of a message category identifier (2), a database of typical message characteristics (5), a determinant of the required virtual network resource ( 8), virtual network setup devices and transmission modes (6), a virtual network configuration control unit and transmission modes (7), a current topology generation unit (9), a virtual network topology database (13), a forming unit Nia packets (3), a multi-channel packet communication device (4); the receiving part (15), characterized by parallel processing of broadband signals in a multi-channel signal transmission system, taking into account the method of forming the topology of the virtual network and consisting of a multi-channel packet receiving device (17), a message generating unit (16) on the receiving side. Reception of packets by radio installations in a virtual network is based on the features of data transmission in broadband communication systems. Packet processing is carried out in accordance with known technologies, which differ in the structure of the network cell in the parameters of broadband signals.

Brief Description of the Figures

The aforementioned features and advantages of the present invention are described in the detailed description with reference to the drawings, in which the following is presented:

figure 1 is a schematic model explaining the formation of a virtual network cell. Designations:

1 - group of transmitting devices (multi-channel transmitter);

2, 3 - groups of relay nodes;

4 - group of receiving devices (multichannel receiver);

figure 2 is a block diagram of a device for a broadband wireless network using relay in parallel composite channels. Designations:

1 - message source;

2 - message category identifier;

3 - packetizer;

4 - device multi-channel packet transmission;

5 - database of message characteristics;

6 - a device for configuring a virtual network and transmission modes;

7 - control unit for setting up a virtual network and transmission modes;

8 - calculator of the required resource of the virtual network;

9 - shaper of the current virtual network topology;

10 - packet network (PRS);

11 - virtual subnet;

12 - transmitting part of the device;

13 - database of virtual network topologies;

14 - message recipient;

15 - receiving part of the device;

16 - shaper messages;

17 - device multi-channel packet reception.

DETAILED DESCRIPTION OF THE INVENTION

The method of accelerated message transmission using a virtual network, adaptable depending on the characteristics of the message and the current capabilities of a broadband wireless network, consists of sequentially performing the above operations:

A. The definition of the category of the input message is necessary to calculate the required network resource when transmitting it. To do this, in the message category determinant (2), figure 2, taking into account the database of message characteristics (5), the value of the main parameters that are used by the calculator of the required resource of the virtual network (8) is calculated. These include message type, message size, delay requirements, and reliability requirements.

B. The calculation of the required resource of a virtual network is carried out by: finding the network capacity

where N is the allowable number of packets on the network (both in broadcast mode and in standby mode in buffer devices); G - virtual network performance; T _ogre - restriction in the form of an admissible time delay of the transmitted message. The performance for double-hop network cells is determined by finding the transmission speed of packets in the relay channels, taking into account the adaptation of the characteristics of the lines in accordance with the method and system for wireless communication networks using relay (patent RU No. 2342800 C2 class. H04L 25/52, 2008) . For a given message size, performance can be represented:

where R _i is the information transfer rate in the ith (composite) relay channel, n is the number of parallel composite channels in the virtual network. A composite channel is two channels connected in series with memory (single-channel systems) corresponding to the first and second communication lines. The speed of information transmission in it depends on the physical characteristics of the communication line, the interference environment and other factors that are taken into account when finding transmission parameters (patent RU No. 2342800 C2 class. H04L 25/52, 2008). Expression (1) as applied to single-channel systems in order to determine the power of a virtual network cell using the expression:

where G _i is the performance of the i-th system representing the composite channel, can be used in the conditions of communication channels with low noise immunity, when packets accumulate in the relay node and wait for further transmission in the composite channel.

Composite channels can be represented by a chain of single-channel systems, relay (with two transit sections) lines, virtual subnets. In the latter case, composite channels degenerate into virtual subnets integrated into a single network. According to the given power of the j-th composite channel is determined by the expression

where k is the number of elements in the circuit of the composite channel. At the same time, a simplification of the identity of the circuit elements was made. In the general case, taking into account complex topologies, the resulting power of the virtual network is found according to expression (1).

The value of the required power of the virtual network determines the topology of the formed network cell - the virtual network for transmitting the message. At the same time, the formation of a virtual network is carried out on the basis of an analysis of the state of a broadband wireless network based on the procedure for setting up a virtual network.

B. Preliminary formation of the virtual network topology is based on the analysis of the required power of the virtual network and the degree of reliability of the transmitted message. If the message has a format exceeding the capabilities of transmission over a single channel (this is especially true in low-speed networks), then the cell topology with parallel channels and various degrees of their use, described by the value of membership functions for soft graphs, is calculated (see Kofman A. Introduction to fuzzy theory sets. - M.: Radio and communications, 1982). The method of forming soft graphs (preliminary topologies) is based on the theory of fuzzy sets by constructing ordered structures of type L ^E , where E is a universal set of arbitrary cardinality, and L is a structured set of membership functions (Gorev P.G., Gorazdovsky T.Ya., Pasechnikov II, Zhelonkin VV Formation of packet radio network structures of varying complexity. - M .: Radio engineering (magazine in the journal). 2001. No. 4. S.25-30). If a cell topology is required in the form of a multi-hop part of a broadband wireless network, then L is endowed with a more complex ordered structure with the presence of upper and lower faces. As a result, the logical structure L ^E characterizing the preliminary network topology can be realized in the form of a torus or other multidimensional soft structure. An important condition for constructing preliminary topologies is the structural redundancy of a broadband wireless network with relays.

D. Configuring a virtual network. Since the information is transmitted in packets and to calculate the network power, it is enough to know the speed capabilities of the composite communication channels (subject to a pre-built topology), then to configure a virtual network, information from potential neighboring relay nodes of a broadband wireless network about their permissible loading is necessary. In this regard, each neighboring node to the node organizing the virtual network is transmitted bandwidth quanta to perform services for the transmission of message packets. One of the options for the quantum value is the fraction of the normalized throughput for transmitting one message packet. Quantums can be transmitted either on demand, periodically, or in a combined way, taking into account the correlation characteristics of the transmitted message flows.

The algorithm for configuring a broadband network to broadcast packets over virtual networks consists of the following steps:

1. Entering the network, exchanging service information and building tables: neighbors and quality of communication channels.

2. In accordance with the data obtained for each i-th type of message, a virtual network option is formed or an α _i -net subnet for a network with a soft topology is recorded in the database. If there is information in the topology database (after the previous service information exchange cycle), the latter are adjusted.

3. Based on the type of message transmitted and its characteristics, the topology for the virtual network is selected.

4. The formation of message packets, their addressing in accordance with the structure of the virtual network — the network cell (the cell is an ordered structured subset of the soft graph). Each element of the graph uniquely corresponds to the packet being processed, the element of the virtual network structure and the code combination used in the broadband signal system.

5. The resource of the virtual network is reserved by means of request signals of the necessary quanta of the throughput of the relay nodes.

D. Multichannel directional transmission and reception by the switching nodes of the virtual network is carried out in accordance with the transmission protocols used in the broadband wireless network and the packet addressing system, carried out in accordance with the construction of the soft topology of the virtual network cell.

A device for broadband wireless communication using relay in parallel composite channels is a necessary element of source nodes, relay nodes, message receiving nodes, is executed by software and hardware and consists of transmitting and receiving parts (figure 2).

The transmitting part (12) in the source node provides the formation of a network cell and implements the method of accelerated message transmission in it. It consists of a message category determinant (2), the first output of which is connected to the input of the typical message characteristics database (5), the output of which is connected by feedback information communication with the second input of the message category determinant (2), the second output of the message category determinant (2) is connected with the input of the determinant of the required resource of the virtual network (8), the output of which is connected to the input of the shaper of the current topology (9), which has two additional inputs and two outputs, the first of the inputs is connected to the output of the topology database in virtual networks (13), the output of which is connected by feedback information with the corresponding input of the shaper of the current topology of the virtual network (9), the second input is connected to the output of the control device for setting the virtual network and transmission modes (7), one of the outputs of which is connected to the corresponding input of the block (9), and the second output of the control unit for setting up the virtual network and transmission modes (7) is connected to the input of the packetizer (3), the second input of which is connected to the output of the determinant of message categories (2), and the output is connected nen with the input of the multi-channel packet transmission device (4), which transmits packets to the packet radio network (10) through the channels of the network cell (11), in which the multi-channel packet reception device (17) of the receiving relay node processes the packets and sends them to the configuration control unit virtual network and transmission modes (7) of the relay node for forwarding and further transmission to the network cell. If the receiving node is the message receiving node, then after processing the signals from the output of the multi-channel packet receiving device (17) are sent to the input of the message shaper (16), the output of which is connected to the message receiver (14).

The device for configuring the virtual network and transmission modes (6) includes: a control unit for configuring the virtual network and transmission modes (7), which provides the formation of a virtual network and implements an algorithm for setting up a broadband network to broadcast packets on virtual networks, as well as converting packets and forwarding them to relay nodes in the case of a multidimensional network cell; shaper of the current virtual network topology (9), constructing the virtual network topology based on the coordination of the requirements and characteristics of the input message and physical capabilities of a broadband network having structural redundancy, as well as taking into account the analysis of the base of network cell topologies; database of virtual network topologies, which stores all the used variants of virtual network topologies used for transmitted standard messages.

The block diagram of the receiving part of the device implements a multi-channel digital broadband signal processing mode on parallel composite channels in a virtual subnet and can be constructed according to well-known multi-channel processing schemes, with a distinctive feature consisting in filtering broadband signals taking into account the correspondence of the signal code structure to the elements of the network cell structure.

The present invention allows:

1. Implement the accelerated mode of message transmission by forming special network cells and parallel transmission of packets in them, adapted in accordance with the characteristics of the message.

2. It is flexible to form network cell topologies for the accelerated mode of message transmission by using the structural redundancy of a broadband wireless network and the method of constructing soft, including self-similar, network structures. The resulting structures make it possible to provide the mode of parallel packet transmission in a virtual network (formed to transmit one message) with a different number of transit sections, including a hierarchical virtual network cell architecture.

3. Form a virtual network for the message, adaptable to its characteristics: message size, priority, statistical characteristics of the message type, requirements for time delay and reliability.

4. To carry out network modulation of network structures by message parameters.

5. To increase the information effectiveness of ORS, which has a strong connectivity. The study (Method of accelerated information transfer with the organization of virtual subnets. / A.A. Khvorov, I.I. Pasechnikov, L.A. Mishina // Information systems and processes: collection of scientific papers / Ed. By prof. V .M. Tyutyunnik. - Tambov; M .; St. Petersburg; Baku; Vienna: Publishing House "Nobelistics", 2009. - Issue 8. - S.9-19) by means of simulation of ORS of 30 nodes, random topology with strong connectivity, with algorithms for determining the shortest paths and with parallel transmission of packets (packet length l = 300 bits, throughput of communication channels C = 2400 bits / s, number of packets in a message - 8) in network cells configured to send messages in an accelerated mode (up to 8 parallel composite channels) showed the advantages of the latter method:

a) performance in the ORS with the determination of the shortest paths according to the Dijkstra algorithm is inferior to the ORS with the parallel transmission algorithm on virtual subnets in the range of input intensities from 30 to 100 messages / s when using 8 parallel composite channels in virtual networks;

b) the application of the parallelism aspect at the network level in solving the routing problem allows minimizing the time delay of transmitted packets at moderate (average) information load and using a large number of parallel paths in virtual subnets: the time delay is less important for a network with 8 parallel composite channels in the input range information load up to 70 messages / s;

c) in conditions of average information load - 60-100 messages / s, the parallel transmission mode has the best indicators regarding information loss (with a sufficiently large number of parallel channels). So, if the input intensity is 80 messages / s in the ORS, where packets are transmitted along the shortest paths, the number of lost packets exceeds 1000, then in a network with 8 parallel composite channels in virtual subnets, there are only dozens of lost packets.

Thus, the accelerated transmission method based on the parallelism mode in specially created virtual networks allows improving the speed and reliability characteristics of networks at moderate ORS loads.

Claims (3)

1. A method of accelerated messaging, combining a method of forming a soft network topology based on its structural redundancy and constructing fuzzy sets with a strict order of graphs that uniquely determine the addresses and topology code, in accordance with the algorithm for constructing soft structures, consisting in displaying an elementary set on the structure belonging (characteristic function) L of a universal set of arbitrary power E and as a result of obtaining a complex structure L ^E with inherited L properties, and a method that adapts the transmission of information by a relay station in accordance with the assessment of the characteristics of the radio channels of the first and second communication lines of the relay line and, thereby, providing cooperative relaying in a network segment with two transit sections, characterized by the formation of a virtual network for implementing the accelerated transmission mode messages on parallel composite channels and including the following procedures: determining the category of the input message, calculating the required virtual resource network based on the analysis of the parameters of the input message and its typical statistical characteristics, preliminary formation of the topology of the virtual network, setting up the virtual network and adjusting the topology based on the estimated capabilities of the broadband wireless network for the formation mode of the network cell for the purpose of parallel packet transmission, multichannel packet transmission over composite channels and filtering them in accordance with the principle of building a virtual network, and based on the formation of a virtual network and devices Features for broadband wireless communications using relay in parallel composite channels. 2. A virtual network with the architecture of a virtual cell of a wireless broadband communication network, which is a multi-channel transmitter (group of transmitters) connected (e) by direct communication channels to a multi-channel relay node (group of relay nodes) interconnected by direct communication channels depending on the number of transit sections and in the last section connected to a multi-channel receiver (group of receivers), characterized by a regular ordered structure and formed by the claimed claimed method for transmitting a single message and implements the parallel transmission mode on composite channels. 3. A device for broadband wireless communication, providing the formation of a network cell and implementing the method of accelerated transmission of messages in it, consisting of a transmitting part and a receiving part, characterized by the presence of a message category determinant in the transmitting part, the first output of which is connected to the database input of typical message characteristics, the output of which is connected by feedback information communication with the second input of the determinant of message categories, the second output of the determinant of message categories is connected to the input of An example of the required virtual network resource, the output of which is connected to the input of the current topology shaper, which has two additional inputs and two outputs, the first of the inputs is connected to the output of the virtual network topologies database, the output of which is connected to the corresponding input of the current virtual network topology shaper, the second input is connected to the output of the virtual network configuration control device and transmission modes, one of the outputs of which is connected to the corresponding input of the unit, and the second output of the configuration control unit The second virtual network and transmission modes are connected to the input of the packetizer, the second input of which is connected to the output of the message category determinant, and the output is connected to the input of the multi-channel packet transmission device, which is connected to the multi-channel packet reception device of the receiving relay node by the virtual network channels of the packet radio network ( or the receiving node), which has two outputs, one of which is connected to the control unit for setting up the virtual network and transmission modes of the relay node, the second one Inonu with input of the messages, the output of which is connected to the receiver of the message.

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