RU2748574C1 - Method for distributing information flows in packet radio network and controlled modular router for its implementation - Google Patents

Abstract

FIELD: communication systems.

SUBSTANCE: invention relates to communication systems, in particular to technologies for building self-organizing radio networks having controlled routers, as well as controlled routers for packet self-organizing radio networks, primarily using narrowband radio channels. The method is characterized by the fact that for the transmission of service and subscriber information, a single radio packet format is used, adapted to low-speed radio channels. A controlled router for implementing the above-described method of distributing information flows in a packet radio network is made in form of a main and backup non-blocking full-access matrix switches, to the inputs / outputs of which switching and routing modules, a control and management module, subscriber interface modules and radio channel interface modules are connected by high-speed serial interfaces.

EFFECT: invention is aimed at increasing the throughput and survivability of self-organizing packet radio networks.

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Description

The invention relates to communication systems, in particular to technologies for building self-organizing radio networks containing controlled routers, as well as controlled routers for packet self-organizing radio networks, primarily using narrowband radio channels.

The technical problem solved by the invention is as follows.

Packet radio networks using narrowband radio channels, for example, of the ultrashort wave (VHF) range, are deployed in order to promptly provide subscribers with data exchange and voice information services in cases where traditional communication networks (wired, cellular, satellite) cannot be used.

These can be hard-to-reach areas with water barriers and rugged terrain, areas of natural disasters and military operations, in which traditional communication networks are either absent or have been destroyed.

The packet radio network, considered in the present invention, is deployed in the area of operations (ROA) by government or commercial structures and consists of many identical routers, interconnected by narrowband radio channels. Routers are controlled modular routers (UMM) to which subscribers and transmitting-receiving equipment of radio channels (modems, receivers and transmitters, antenna-feeder routers) are connected.

To assess the novelty of the claimed solution, let us consider a number of known technical means of a similar purpose, characterized by a set of features similar to the declared router.

A known method of transmitting data over a wireless mesh network according to RF patent No. 2476031, containing the formation of the first cell header, and the first cell header includes a plurality of fields, expanding the first cell header by adding a second protocol header to its beginning to form a second cell header, and the second the protocol header has the same format as the first protocol data unit (PDU) header, and the second cell header is inserted into the PDU before the first protocol header. This patent describes the address fields of a cell (packet) header for a wireless mesh (self-organizing) network, however, the described header is intended for high-speed networks in which additional external source and destination address fields are included as extensions of the packet (cell) header, which leads to an increase in the length packet header, which is undesirable for low-speed radio networks.

A known method of forming a hybrid mesh network for dispersed users according to RF patent No. 2504926, related to the technology of building wireless self-organizing networks with a central station. The network is made up of segments containing a central station and a group of subscriber stations, each of the stations having two transceiver paths. One of the paths is used for normal operation in the network, and with the help of the second transceiver path, the subscriber station listens to the reserve frequency bands from the system range, specially allocated for service or emergency transmissions. When an unoccupied reserve frequency band is detected, the subscriber station transmits a beacon frame, which is used by the stations that have lost communication with the network to restore access to the network if it is impossible to establish communication with the central station of any of the network segments.

This technical solution was adopted as a prototype of the first independent object of the claimed invention.

This solution provides an increase in the ability of the network for self-healing, flexible restructuring of its structure and operational redistribution of traffic in case of uneven loading of communication channels, but the use of a central station reduces the reliability and flexibility of building a radio network.

Known managed multiservice router according to RF patent No. 172987, however, it belongs to the field of building fast Ethernet routers (local area network protocol with random access to the transmission medium) and does not cover the area of packet radio networks.

Known gateway for automatic routing of messages between buses according to the patent of the Russian Federation No. 2415511, which includes several communication modules for temporary storage and transmission of messages over the buses and a gateway control unit connected to the communication modules via the system bus for messaging with the ability to receive from each communication module information about the appearance in it of a message intended for routing, indicated as an external event. The invention provides the possibility of creating a gateway for automatic routing of messages between buses, forwarding messages without influence and regardless of the load of the central processor.

This technical solution was adopted as a prototype of the second independent object of the claimed invention.

The objective of the invention is to create a technology for distributing information flows in a packet radio network, which increases the reliability and flexibility of building a radio network, as well as to create a controllable modular router for low-speed packet radio networks using a single radio packet format for datagram mode and logical connection mode.

The essence of the first independent object of the invention is expressed in the following set of essential features sufficient to solve the technical problem indicated by the applicant and obtain the technical result provided by the invention.

According to a first independent aspect of the invention, a method for distributing information streams in a packet radio network is characterized in that a single radio packet format is used to transmit all types of service and subscriber information, which is adapted to low-speed radio channels.

In addition, the first independent object of the invention is characterized by the presence of a number of additional optional features, namely:

- two routing modes can be used: the mode of separate independent packets or the mode of the flow of interconnected packets along the previously established best route at a given time;

- each logical connection (LAN) established in the radio network is assigned a unique identifier consisting of the numbers of logical channels and MAC addresses of routers between which this connection is established;

- to establish and break logical connections in the network, transport layer control packets are used.

The essence of the second independent object of the invention is expressed in the following set of essential features sufficient to solve the technical problem indicated by the applicant and obtain the technical result provided by the invention.

According to the second independent object of the invention, a controlled modular router for implementing the above-described method of distributing information flows in a packet radio network is made in the form of a main and backup non-blocking full-access matrix switches, to the inputs / outputs of which switching and routing modules, a control and management module, modules subscriber interfaces and radio channel interface modules.

In addition, the second independent object of the invention is characterized by the presence of a number of additional optional features, namely:

- routing of datagrams is carried out in the switching and routing module;

- the number of switching and routing modules is determined by the maximum flow rates of datagram packets entering the router from subscribers and from the radio network;

- in the presence of several switching and routing modules, the monitoring and control module is configured to operate either in the enhanced performance mode or in the enhanced reliability mode;

- routing of radio packets in the logical connection mode is carried out by the radio channel interface module and the subscriber interfaces module according to their logical connection tables without the participation of the switching and routing module;

- the controlled router is capable of simultaneously receiving and transmitting radio packets at different frequencies, intended for one or different nodes located in the electromagnetic availability zone;

- a managed router, the sequence number of which coincides with the current cycle number in the superframe, transmits on all allocated frequencies in the service channel slot its current information about the connectivity of routers in the network and the numbers of slots it has reserved;

- a managed router, in which radio packets of the subscriber load, as well as control packets of the network and transport layers, are routed between the modules through the matrix switch, and the technological control of the modules is carried out by the control and management module through the internal local network IP / Ethernet (Internet Protocol) ...

The claimed set of essential features ensures the achievement of a technical result, which consists in increasing the throughput and survivability of self-organizing packet radio networks, as well as in expanding the list and improving the quality of communication services provided to heterogeneous subscribers in the deployment area of the packet radio network when using the logical connection mode, implemented in controlled modular routers.

The essence of the proposed technical solution is illustrated by the drawing, in which FIG. 1 shows a diagram of the organization of a VHF radio network, FIG. 2 illustrates a data link layer structure in Time Division Multiply Access (TDMA) mode, FIG. 3 is a block diagram of a controlled modular router (UMM), FIG. 4 is a diagram of routing of packet streams in the UMM in modes of transmission of datagrams and logical connections

The drawing indicates:

100 - controlled modular router (UMM);

101, 102, 103 - interface radio channel module (MIR);

104 - main control and management module (MCU);

105 - monitoring and control module (MCU) backup;

106 - Ethernet subscriber interface module (MAI);

107 - module of subscriber interfaces S1-FL-BI (synchronous bi-pulse physical line interface);

108, 109 - switching and routing module (MCM);

110 - interface of the local area network (LAN) Ethemet / IP / UDP main (User Datagram Protocol);

111 - LVDS interface (Low Voltage Differential Signalling);

112 - subscriber interface Ethernet 1000 Base-FX, Ethernet 1000 Base-TX;

113 interface S1-FL-BI for connecting voice subscriber terminals;

114 - RS-232 interface (asynchronous serial interface) for connecting modem equipment of radio channels;

115 - matrix switcher (MK) main

116 - backup matrix switch;

117 - interface of the local area network (LAN) Ethernet IP / UDP backup;

118 - Ethernet IP / UDP interface for connection to the operator's PC (personal computer).

The claimed method using the claimed managed modular routers is implemented as follows.

FIG. 1 shows an example of building a network of such a radio network, consisting of five routers, which are assigned MAC addresses at the MAC (Media Access Control) sublayer: '01, '02', '03', '04', '05' ...

Each router, located on the ground, forms around itself a zone of electromagnetic accessibility (in Fig. 1, the zones are shown by dotted circles).

For example, if on frequency f ₁ router '03' is in the electromagnetic reach of router '01' and router 01 'is in the electromagnetic reach of router' 03 ', then there is a two-way radio channel between them, if not, then there is no radio channel between these routers ...

FIG. 1 shows the presence of radio channels between routers with MAC addresses '01' and '02'; '01' and '03'; '02' and '03'; '03' and '04'; '03' and '05'; '05' and '04', and its absence between routers '01' and '05'; '02' and '04'; '01' and '04'.

The radio network is organized in such a way that each router has at least two or three adjacent routers within its electromagnetic reach.

The number of routers in the radio network organized in the ROD is variable, i.e. routers in the course of operational actions can connect and disconnect from the radio network. The maximum number of routers in the radio network "M" is determined by the area of the ROD "S", the maximum admissible number of hops in the radio network "k", which determines the maximum delay time of information in the radio network, and the minimum admissible number of backup routes between any pairs of "sender-recipient" - " r "which in turn determines the connectivity of the router in the radio network.

Subscriber terminals can connect to routers via wired or fiber-optic communication lines, as well as via Wi-Fi (Wireless Fidelity) wireless access points.

FIG. 1 shows the connection of subscribers U1, U2, U3, U4, subscribers U1 and U4 are subscriber voice terminals connected to the routers of the radio network via synchronous interfaces C1-FL-BI; U3 and U2 - subscriber data transmission points are connected to the UMM via the Ethernet interface.

Each router in the radio network is terminal for subscribers connected to it and transit for subscribers connected to other routers, i.e. in each router, the received packets from the radio channel are analyzed according to the following criteria:

- if the recipient address specified in the header of the radio packet matches the MAC address of this router, then the packet is forwarded to one of the subscribers connected to this router,

- if not, then the radio packet is routed to the radio channel for forwarding to adjacent routers that are in the electromagnetic reach.

There are two routing modes used in a radio network:

- separate independent packages (datagrams);

- the flow of interconnected packets along the currently established best route (logical connection).

At the physical level, the radio network considered in the invention is organized on the basis of narrowband radio channels with a bandwidth of 6.25; 12.5; 25 and 50 kHz using well-known digital modulation and noise-correcting coding in narrowband channels, for example, FSK (Frequency Shift Keyng), DQPSK (Differential Quadrature Phase Shift Keyng), convolutional and turbo codes [ 3].

At the channel level, the frequency-time division of the radio channel is carried out, combining the organization of the operation of routers at fixed frequencies f _i (i = from 1 to I, where I is the number of nominal frequencies allocated for use in the radio network), and in addition, at each frequency, multiple TDMA access, FIG. 2 [3].

In TDMA mode, the transmission and reception time is divided into cycles of T seconds, and the cycle duration should not exceed the admissible time of delivery to the subscriber of information of this type (speech, data) - T _D.

If the information transmission route passes through several nodes (has k hops), then Т≤T _D / k.

The cycles, in turn, consist of identical time slots with a duration of t seconds, T = n * t, where n is the number of slots in the cycle.

Each router can receive and transmit radio packets in time slots at allocated frequencies, and one router can technically simultaneously receive and transmit information at different frequencies intended for one or different routers (Fig. 1).

Slots are used both for transmitting datagrams and for transmitting streams of packets in logical connections. In the latter case, when establishing a logical connection, slots are reserved for the duration of the communication session.

Synchronization of time scales of all routers is carried out by highly stable local generators, periodically adjusted according to the signals of the exact time of global navigation satellite networks.

In the considered radio network, in contrast to the prototype, distributed control of access to the radio channel is used without the allocation of individual nodes as access coordinators. For this, the following algorithm is used.

Each router is assigned a sequence number m from 1 to M, where M is the maximum number of routers operating in the radio network. M cycles form a supercycle, duration _Tsc = M * T seconds.

A router whose number m coincides with the current cycle number in a superframe, in the first slot (service channel slot) of this cycle, transmits to all routers within its electromagnetic availability zone its current information about the network connectivity and the numbers of its reserved slots on each allocated frequency.

Thus, at each frequency during each superframe, all routers in the radio network are guaranteed to transmit current information about their state, which is taken into account in each router when building routes and reserving slots.

It is considered that the amount of information describing the connectivity and the numbers of the reserved slots transmitted in the overhead channel slot is fixed at L _sl bits. Then the duration of the slot in which the service information is transmitted:

_cl t = L / V _r + t _{communications} + t _k,

where: V _p is the information transmission rate in the radio channel, t _zi is the duration of the guard interval, which takes into account the propagation time of the radio signal to the maximum distance between the routers in the radio network, t _k is the duration occupied by the bits of the checksum of the data block, Fig. 2.

The checksum of the data block transmitted in the service channel slot can be calculated, for example, using the CRC-16 algorithm (Cyclic Redundancy Check) used in the HDLC protocol (High-Level Data Link Control - protocol of high-level control of the data transmission channel) and described in [2].

In each cycle, all routers whose numbers do not coincide with the current superframe number receive data in the service channel slot (for routers outside the electromagnetic reach of the transmitting router, this will be noise), calculate the checksum of the data block and compare it with the data received on the interval t _k .

If the checksums do not match, then the information contained in this slot is considered distorted (or noise), and it is not taken into account in the current cycle when updating information about connectivity and numbers of reserved slots, in the expectation that an undistorted one will be received in the next superframe. information from this router.

Since all slots, including the service one, have the same duration, you can determine the number of slots in a cycle: n = T / t.

By varying the value of t _zi , an integer value of n is provided.

Information slots, in a cycle, n-1 in number, are distributed as follows:

d≥l slots are used for random access and are used for transmitting datagrams between routers, n-d-1 slots are used for transmitting radio packets in logical connection mode.

Thus, each router on the same frequency can use d slots for transmitting radio packets in random access mode and serve up to n-d-1 logical connections for which slots were reserved when establishing logical connections.

The problem of collisions in random access slots is solved using the binary exponential rollback algorithm used in the Ethernet protocol [2]. If the number of logical connections served by a router in a given direction exceeds n-d-1, then between adjacent routers for logical connections for the duration of the communication session, a slot reservation procedure is performed. Radio packets containing requests to reserve slots for logical connections are datagrams and are sent in random access slots.

Each data slot includes a guard interval and a data link layer, such as an HDLC frame. The HDLC frame format is shown in FIG. 2. In a radio link, an HDLC frame performs functions similar to an Ethernet frame for a wired link. The HDLC frame contains a 3-byte header, a payload field, the length of which is determined by the data rate in the radio channel and the slot duration, and two bytes of the checksum. Thus, the amount of service information in an HDLC frame is only 5 bytes, versus 26 bytes in an Ethernet frame [2].

The fields of the source and destination MAC addresses in the HDLC frame header, each one byte long, contain the MAC addresses of the adjacent routers between which the radio link is established. The control field determines the type of frame - service, data, speech. The type of frame determines the method of processing it at the reception and the need to re-ask if distorted - distorted speech frames are not asked again. For service frames and frames containing data packets, a re-request procedure is organized in accordance with the HDLC protocol. If one or more radio packets placed in the payload field of an HDLC frame have a shorter total length than the length of the payload field, then after the checksum bytes of the HDLC frame and to the end of the slot, placeholder bytes encoded '7E' in hexadecimal.

An example of calculating the parameters of the TDMA mode.

For М = 30 (the maximum number of routers in the radio network, typical for carrying out operational actions), k = 4 (the maximum number of hops in the radio network), T _D = 300 ms (admissible time of delivery of voice information to subscribers), V _p = 64 kbit / s (the rate of information transmission in a radio channel with a bandwidth of 50 kHz) and L _sl = 100 bytes (the amount of information about connectivity and reserved slots transmitted by routers in the slots of the service channel), we get:

- cycle time:

T = 300/4 = 75 ms;

- the duration of the superframe, the period of updating information about the connectivity of logical connections in the radio network:

_Tsc = 0.75 * 30 = 2.25s;

- the duration of the transmission of service information:

t _w = 100 * 8/64000 = 12.5 ms;

- duration of transmission of two bytes of the checksum in the service channel slot:

t _ks = 16/64000 = 0.25 ms;

- the duration of the guard interval is chosen in such a way that it takes into account the delay time of the radio signal in the radio channel of the maximum length, organized in the ROD. For t _zi = 2.25ms, the length of the radio channel will be 675 km, which is quite enough for all types of ROD, where VHF packet radio networks are deployed;

- slot duration:

t = 12.5 + 0.25 + 2.25 = 15 ms;

- number of slots in a loop:

n = 75/15 = 5.

In the frame structure considered in this example, one slot out of five is a service slot, two slots are allocated for transmitting radio packets in the random access mode (transmitting datagrams) and two for transmitting information over logical connections.

At the network level, the exchange of information between routers (UMM) is carried out by radio packets, the format of which is shown in Table 1.

The length of the radio packet header is 7 bytes, in contrast to the IP packet header, which is 20 bytes, which can significantly reduce the amount of transmitted overhead information, the amount of which is critical for low-speed narrowband radio channels.

The header fields "Network address of the recipient's node" and "Network address of the sender's node" contain the network addresses of the terminal routers between which information is exchanged (to which network subscribers are connected).

Router network addresses are in the following format.

The first byte is the MAC address of the node in the radio network. In this case, the most significant bit (leftmost) of the first byte indicates the transmission mode of the packet (here, byte lending is used from left to right). If the most significant bit of the first byte is 0, then the radio packet is a datagram. In this case, the remaining 7 bits of the byte determine the MAC address of the node in the radio network. The second in order byte of the network address for datagrams contains the address of the subscriber interface, which has the following structure: bits (8-5) determine the type of interface, bits (4-1) the serial number of the interface for connecting the corresponding subscribers to the UMM.

The types of subscriber interfaces connected to routers are shown in Table 2.

The table indicates:

Е1 (G.703) - primary digital channel with a speed of 2048 kbps

Ethernet100 / 1000 Base-TX - local area network interface over twisted pair with a speed of 100 Mbit / s or 1000 Mbit / s

IEEE.802.11 - Random access wireless LAN

C1-FL-BI - synchronous bi-pulse physical line interface (GOST 27232-87)

RS-232/485/422 - serial data interface

Each of the types of subscriber interfaces can have up to 16 interfaces of the same type. If the number of interfaces of this type should be increased (for example, to have 32 Ethemet100 / 1000 Base-TX interfaces), then reserved field codes are used (Table 2).

If the most significant bit of the first byte is 1, then the radio packet is transmitted in logical connection mode. Similar to datagram mode, the remaining 7 bits of the first byte in this mode determine the MAC address of the router in the radio network. The second byte in the logical connection mode contains the number of the logical channel assigned to the subscriber interface of the receiver or sender node, which is presented in Table 3.

The four-bit "Protocol" field in the radio packet header contains the encoding of the packet types shown in Table 4.

The 12-bit Timestamp field contains the time value in ticks. The first two bits define the tick price code, the next 10 bits - the number of ticks, maximum 1024. The tick price code is set depending on the characteristics of the radio network channels and can have the following meanings:

00 - tens of milliseconds;

01 - hundreds of milliseconds;

10 - seconds.

The 8 - bit field "Data field length" in the header of the radio packet determines the number of information bytes contained in the data field of the radio packet and can vary from 0 to 255.

The length of the data field of the radio packet must match the length of the payload data field of the HDLC frame, which in turn is determined by the slot duration calculated from the TDMA parameters. Therefore, if the length of subscriber data blocks (messages) arriving at the router exceeds the maximum length of a radio packet, then the router must perform the operations of splitting the subscriber message into radio packets when transmitting it to the radio channel and assembling subscriber messages from radio packets received from the radio channel.

Control packets of various levels and single-packet subscriber messages act as datagrams in the radio network (the type of packet is indicated in the "Protocol" field of the radio packet header (Table 4).

In this case, the decision on the choice of the route of the datagram packets is made independently in each router using one-step datagram routing tables (Table 5), periodically updated by the routing control subsystem based on the actual information about the network connectivity received in the service channel slot from all active routers in the radio network. ...

To obtain up-to-date information about the connectivity of a radio network and build routing tables on its basis, the FSR protocol (Fisheye State Routing - a proactive routing protocol that takes into account the remoteness of nodes) [5] can be used.

Packet routing in the logical connection mode is carried out along the established fixed routes (logical connections) between the end nodes and is implemented by the transport layer protocol discussed below.

The logical connection mode ensures the stability of the packet transmission characteristics, including the minimization of the average time and variance of packet delay in the network, which is essential for the transmission of voice information.

Unlike TCP (Transmission Control Protocol [2]), which provides end-to-end connection between end nodes via an IP datagram network on "good" quality channels, the proposed logical connection protocol fixes the route of packets through the allocated connecting routers and radio channels, and thereby ensuring the stability of its temporal characteristics for the duration of a session of information exchange between subscribers.

This feature is determined by the fact that narrowband radio channels have a low bandwidth (on average 9600 bit / s) and a high BER> 10 ^-3 (Bit error Ratio).

on which protocols using IP format packets, including TCP, are inoperable [1].

The controlled modular router UMM, which is part of the nodes of the considered radio network, is a packet router for building self-organizing networks.

FIG. 3 UMM 100 consists of the main 115 and backup 116 non-blocking full-access matrix switches (MC), to the inputs / outputs of which functional switching and routing modules (MCM) 108, 109, main 104 and backup 105 control and management modules are connected by high-speed LVDS 111 serial interfaces (MKU), modules of subscriber interfaces 106 and 107 (MAI) and modules of interfaces of radio channels 101, 102, 103 (MIR).

Unlike the prototype, where messages are routed between serial buses, UMM functional modules exchange radio packets through high-speed matrix switches.

Diagrams of non-blocking full-access matrix switches are given, for example, in [2].

The number of functional modules of each type is variable and is determined by the requirements for bandwidth, channel capacity and reliability imposed on the UMM by the radio network. The main difference from the prototype is that the prototype describes a modular, scalable structure for building fast Ethernet LAN routers that access a common data distribution bus. UMM uses a non-blocking matrix switch instead of a bus, which allows to increase the bandwidth of the router. In addition, the UMM is designed to work in narrow-band radio communication networks, in which a radio packet with a single header format, discussed above, is used for all types of transmitted information. UMM in a radio network provides routing of packet streams of incoming (to the network) and outgoing (from the network) traffic (Fig. 4).

When processing incoming (to the radio network) traffic, the MAI 106, 107 receive information from the subscribers connected to them via interfaces 112, 113, convert them into radio packets and, depending on the mode set for this type of traffic, send them through the MC or to the MCM (datagram mode), or to the corresponding WORLD (virtual connection mode).

In this case, in the MAI virtual connection mode, in accordance with its logical connection table (TLC), Table 3 replaces the low byte of the network address with the logical channel number.

MCM on the datagram routing table (TMD), Table 5 for each datagram packet selects the best route at a given time, determines the physical address of the MIR and sends it through the MC for transmission to the radio channel.

MIR encapsulates the packet in an HDLC channel frame and transmits it to the radio modem. MIR also implements time division multiple access between nodes (TDMA), discussed above.

Each MIR interfaces 114 are connected to the radio channel equipment operating at one of the allocated frequencies 5. The number of MIRs (101, 102, 103) is determined by the number of radio channels connected to this UMM and operating at different frequencies.

If there are several MCMs in the UMM (108 and 109), the packet from the MAI is forwarded to the free (least loaded) MCM based on the information about the load received from the processor control and monitoring module (MCU). The required number of MCMs is determined by the maximum expected rates of streams of datagram packets arriving at this UMM. In the presence of several MCMs, the UMM can operate either in the increased performance mode (load balancing between MCMs) in case of an increase in the intensity of the incoming packet flow, or in increased reliability (hot standby) to ensure high availability. Switching of operating modes (increased reliability or productivity) is carried out and controlled by the monitoring and control module by the operator's commands from the PC.

The routing of radio packets in the logical connection mode is carried out by the MIR and MAI UMM according to their logical connection tables, without the participation of the MCM, Fig. 4, which reduces the processing time of the package in the UMM by 30%.

Table 6 and Table 3, respectively, are examples of MIR and MAI tables for UMM '01'.

When processing outgoing (from the radio network) traffic, the MIR receives a channel frame from the radio channel and extracts a radio packet from it.

Further, depending on the destination address and forwarding mode specified in the header, the radio packet is sent through the MC:

- in MKM, if the datagram mode is specified in the header of the radio packet;

- to one of the MAIs in accordance with the logical connection table (Table 6), if the logical connection mode is set and the recipient's network address specified in the packet header matches the network address of this node);

- to one of the WORLD in accordance with the table of logical connections, (Table 6), possibly in the same one when rearranging radio packets in slots at the same frequency, if the logical connection mode is set and the recipient's network address specified in the radio packet header does not match the network the address of this UMM (Fig. 4).

The MCM analyzes the network address of the recipient in the header of the radio packet received from the MIR, and if the recipient's address matches the address of this node, in accordance with the table of subscriber interfaces (TAI) (Table 7), determines the physical address of the corresponding MAI and sends it the packet through the MC (Fig. . four).

If the recipient's network address does not coincide with the address of this node (the datagram is transit), then the physical address of the MIR is determined according to the datagram routing table (Table 5), to which the radio packet should be sent. MIR encapsulates the received network packet into an HDLC channel frame and transmits it to the radio modem via interface 114. MAI converts radio packets received from MKM and MIR into subscriber messages and forwards them to the appropriate subscribers via interfaces 112, 113 in accordance with the table of subscriber lines (TAL) (Table 8).

If the logical connection mode is set, then according to the logical connection table (Table 3), the logical channel number in the low byte of the network address is replaced with the subscriber interface address. MCU 104 main and 105 backup collect information about the state of all functional modules of the UMM, including MC, control their operation modes via interfaces 110, 117 organized for these purposes by the internal Ethernet LAN using the IP / UDP protocol. To interact with the operator, MCUs are connected via a separate external LAN Ethernet 118 channel to the operator's PC. MCUs load into functional modules the routing and address information generated on the control PC, the distribution of requests for organizing communication sessions from subscribers connected to this UMM to the MAI, disconnection of faulty modules and connection of backup modules (including MC) if available. MCUs operate in hot standby mode, providing, in case of failure of the main MCU 104, control and monitoring of all UMM modules via the backup internal LAN Ethernet 117.

Switching to the backup MKU 105 and back switching occurs at the command of the operator from the PC. All UMM functional modules - MKM, MKU, MIR, MIA and MK can be implemented on the basis of the System-on-Chip VLSI (SoC) FPGA Z-7020 from Hilinx, or similar in functionality and performance SoC [4]. SoC FPGA Z-7020 combines a 2-core Cortex-A9 processor system used as a computing core for all UMM functional modules and an array of programmable logic blocks for implementing all types of MAI and MIR interfaces.

This solution allows to reduce the number of microcircuits used in the UMM, which in turn reduces the weight and size characteristics, power consumption and the cost of the router.

Logical connections (LAN) are established in the radio network at the transport level in order to limit the maximum number of subscriber connections (of each type) served by the UMM, as well as to ensure the required quality of service (timely delivery of information) along the established routes. Logical connections are established and fixed in UMM subscriber interface modules, which are terminal for subscribers organizing a communication session.

When establishing a LAN, logical channel numbers are allocated on each terminal UMM. These numbers are indicated (after successful passage of the logical connection procedure) in the lower bytes of the receiver's and the sender's network addresses in the headers of radio packets transmitted over the network and, together with the higher bytes (MAC addresses of routers), are unique identifiers of logical connections in the network.

Thus, a logical connection for a given pair of terminal routers consists of a chain of radio channels between them with slots reserved in them included in this route, which is the most optimal in terms of the number of hops and throughput of radio channels at the time of connection establishment. After a logical connection is established and until it is broken, in all routers included in the route of this logical connection, information packets are routed to MAI and MIR according to logical connection tables (TLS) (Tables 3 and 6).

Transport layer control packets are used to manage logical connections. The list of commands and responses for managing logical connections is given in Table 9, while the code 02 should be indicated in the header of the radio packet in the "protocol" field.

Logic connection mode consists of 3 phases:

a) establishing a logical connection;

b) data transmission over an established logical connection with procedures (if necessary) limiting the incoming flow and handshaking at the level of protocol blocks of subscriber applications

c) breaking a logical connection.

Phase (a): the router's MAI accepts applications from the MCU for organizing communication sessions between the subscribers of the radio network. The application specifies the names of the recipients and senders of the subscribers, the type of connection - data, speech, the required information transfer rate. This information is used later in the formation of commands to control logical connections. The establishment of a logical connection is initiated by the transport layer command "Establish connection" placed in the data field of the radio packet and containing the command code, the command sequence number and information about the logical connection (Table 10), consisting of the 8-bit number of the selected logical channel of the initiator node, the type of connection ( data or speech), the requested data transfer rate in the logical connection, the timestamp of the packet sending (hh.mm.ss).

Cyclic command number (0-15) allows numbering commands and responses within a logical connection. The answer number must match the number of the command to which the answer is given. 8-bit numbers of logical channels are fixed in the interface modules of the terminal routers (sender and receiver) for the duration of the communication session and are further used to identify (determine the belonging) of packets to specific subscribers in the established logical connection.

Each MAI has the number of logical connections assigned to it (by the UMM control operator) for each type of subscriber interface: m _c1-i , m _eth , etc. The total number of logical connections simultaneously established from all interfaces of one UMM cannot exceed the value set by the control operator (by addressing - no more than 256). The number of logical connections established by the MIR over the radio channel between adjacent routers is determined by the total subscriber data transmission rate on these LANs and the maximum data transmission rate in the radio channel, which must exceed the total subscriber speed, by the amount of overhead costs for the lengths of radio packet headers and information frames. A radio packet containing a command to establish a logical connection is routed and transmitted in the radio channel as a datagram, recording the route as it passes through the nodes in the form of a string written to the TLS MIR and MAI (Tables 6 and 3, respectively). If the number of established logical connections of this type, serviced by the MAI, has reached the maximum value (there are no free numbers of logical channels), and a new claim arrives, then the priority of the newly arrived claim is compared with the priorities of the already established logical connections according to the table of logical connections of this MAI (Table 3). If there is a logical channel with a lower priority (higher number) in the TLS, then this connection is terminated by sending the “Disconnect” command with a corresponding notification to the subscribers (see the procedure for disconnecting logical connections). If the priority of the newly arrived claim is lower than the priority of the already established LANs, the claim is queued to await the release of the logical channel number. In case of successful reservation on all parts of the route, a radio packet with a connection confirmation command is sent from the MAI of the recipient router (Table 11).

This packet is directed towards the sender and routed along the formed route.

If on any part of the route the logical connection reservation procedure cannot be performed (for example, the requested speed cannot be reached in the radio channel), then the initiator sends a connection establishment refusal packet to the router indicating the reason for the refusal: there are no free channels, the requested speed is in this channel could not be established, an opposite call was detected (Table 12).

Decimal refusal reason code:

- 01 - the subscriber is absent (not connected) at the recipient's address (network address XXYY);

- 02 - the subscriber is busy (not ready);

- 03 - the requested subscriber speed is not provided by the recipient by the subscriber.

- 04 - no response from the recipient's subscriber

Phase (b): In the process of transferring information over a logical connection, the procedures for limiting the flow, re-requesting packets lost during the transfer, defined at the application level, can be applied. When transmitting radio packets over a logical connection, the second byte of the sender and receiver addresses is replaced by the TLS MAI with the set logical channel number and the packets are routed directly between the MAI and the MIR, bypassing the datagram routing processors (Fig. 4). In case of procedural errors associated with constant exceeding of timeouts of waiting, unauthorized losses or duplicate packets, the procedure can be performed to discard all packets located in routers and related to this logical connection without breaking it. In this case, the MAI of the command sender must receive a reset confirmation from all route nodes, otherwise, after the timeout expires, the logical connection will be broken. After receiving the reset confirmation, the sender can resume the transmission of packets over the logical connection by the MAI. If a channel is lost in one or more sections of a logical connection (if it is detected that it is impossible to transfer information), the logical connection is broken (see Fyaz c), informing the end nodes about the reason for the break and an attempt to re-establish the connection (if necessary), possibly along a new route.

Phase (c): Po. the end of the data transmission session is followed by the procedure for breaking the logical connection initiated by either side (Table 13).

Decimal code of reason for disconnection:

-01 - hang up the subscriber;

-02 - timeout for waiting for data on reception

-03 - session timeout

-04 - disconnection by the UMM operator

-05 - expiration of the timeout for waiting for data from the subscriber for transmission

-06 - disconnection of a logical connection by a higher-priority subscriber

-07 - an error was detected in the TLS

-08 - disconnection of the MIR connection due to communication channel failure

After confirming the disconnection of the logical connection (Table 14), the number of the logical channel used in it is released and can be reused. All packets remaining in the UMM and related to this logical connection must be erased.

The declared technology of distribution of information flows in a packet radio network provides an increase in the throughput and survivability of packet self-organizing radio networks, as well as in expanding the list and improving the quality of communication services provided to heterogeneous subscribers in the area of deployment of a packet radio network using the logical connection mode implemented in controlled modular routers. The claimed technology and controlled modular routers can be implemented using known technical and technological means.

Bibliography:

1.https: //www.isode.com/whitepapers/performance-of-ip-applications-over-hf-radio.html.

2. Tanenbaum E. Computer networks. St. Petersburg: Peter, 2002.848 p.

3. Sklyar B. Digital communication. Theoretical foundations and practical application. Moscow: Science and Technology, 2003.464 p.

4. Kalachev A. Multicore configurable computing platform Zynq-7000 // Modern electronics №1 2013 p. 22-31.

5. Glagoleva M. Classification and analysis of methods in Mesh-networks. 155 2008 p. 173-185.

Claims (6)

1. A method of distributing information streams in a packet radio network, characterized in that for the transmission of service and subscriber information, a single radio packet format is used, adapted to low-speed radio channels, while two routing modes are used: the routing mode of separate independent packets and the routing mode of the flow of interconnected packets in advance the established best route at the moment. 2. The method according to claim 1, characterized in that each logical connection established in the radio network is associated with a unique identifier consisting of MAC addresses of logical channel numbers, routers between which this connection is established. 3. The method according to claim 2, characterized in that transport layer commands and responses are used to establish and terminate logical connections in the network. 4. A controlled router for implementing the above-described method of distributing information flows in a packet radio network, characterized in that it is made in the form of a main and backup non-blocking full-access matrix switches, to the inputs / outputs of which switching and routing modules, a control and management module are connected by high-speed serial interfaces, subscriber interface modules and radio channel interface modules, while the number of switching and routing modules is selected from the condition of ensuring the maximum flow rates of datagram packets entering the router from subscribers and from the radio network, and radio packets are routed in the logical connection mode by the radio channel interface module and the subscriber interface module according to their logical connection tables without the participation of the switching and routing module. 5. The router according to claim 4, characterized in that it is configured to simultaneously receive and transmit radio packets at different frequencies, intended for one or different nodes located in the electromagnetic availability zone. 6. Router according to claim 4, characterized in that the radio packets of the subscriber load, as well as control packets of the network and transport layers are routed between the modules through the matrix switch, and the technological control of the modules is carried out by the MCU through the internal local IP / Ethernet network.

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