The method of synchronization data packets

 

(57) Abstract:

The invention relates to a method of synchronization data packets between the wireless terminal and the respective base station and can be used in digital wireless communication systems with multiple access with time division channels to ensure the correct reception of packets received with different delays caused by the effects of signal propagation. The technical result - improving the accuracy of synchronization data packets. The essence of the method: wireless target device (T) re-consistently passed up to the maximum number of times the first packages to their base station (BS), shifting them forward in time at each re-transmission on the number of binary digits, depending on the maximum guard interval until a response is received from the base station (BS) after ensuring correct synchronization with them. 2 S. and 1 C.p. f-crystals, 2 Il.

The invention relates to a method of synchronization data packets between the wireless terminal and the respective base station. This method in particular, can be used in digital wireless systems, CB, received with different delays caused by the effects of signal propagation.

Many communication systems, containing a group of wireless terminal devices and a number of base stations have been developed on a small range (pichacani), for use indoors, where the distance between the wireless terminal devices and the base stations is very small. Currently, the initial application of these systems revised in order to use them on larger spaces, due to the increased distance between the base station and wireless terminal devices, for use as an alternative to cellular systems. In such communication systems, the wireless terminal device receives its reference signal time base from the base stations, so that the moments of transmission base stations coincided with moments of reception of the wireless terminal devices, and Vice versa.

Due to the configuration, which originally had a wireless system, developed standards for this technology did not provide for measures to overcome the problems caused by the delay spread due to distance me what Ricoy reception on time, when they should be taken that leads to total or partial loss of information channels. This is especially critical in systems with multiple access with time division multiplexing (MDR) and high bit rate that can occur such problems that have virtually no consequences for distances between base stations and wireless terminal devices inherent in the initial configuration of these systems.

The European standard ETS 300 175-3 "European cifrovaya radio (ECRS), Common interface, part 3: Level access control environment", October 1992 , developed by the Technical Committee RES (Device and communication systems), in Appendix D, "Synchronizing", page 186, offers for this system ECRS three types of synchronization between the wireless terminal devices and the base stations for accurate transmission and reception of packets exchanged data: packet synchronization, frame synchronization and multiframe synchronization.

This European standard does not introduce any procedures compensate for the delay due to the spread (which prevents the implementation of proper synchronization between the base stations and the problem in applications, are addressed in the system. Therefore, this European standard does not offer solutions to the problem, which occurs in the base stations, when the packets coming from different wireless terminal devices associated with the base stations are received with different delays due to the changing distance between the wireless terminal devices and the base stations, which may cause mutual interference between the two devices, the consequence of which may be complete or partial loss of information channels.

Due to the foregoing, the object of the invention is to provide a precise synchronization between the wireless terminal devices and their base stations with increasing distance between them, so that packets coming from these wireless terminal devices, just taken at the base stations without the propagation delay caused by the distance that impede the achievement of precise synchronization between the base station and wireless terminal devices that will eliminate the problem of overlapping packets with complete or partial loss of information or channels.

The present invention provides a method syncprovider target device are located at some distance from their base stations, moreover, this procedure is applicable for digital radio systems.

This method is offset forward in wireless terminal devices of the time of transmission of their packets relative to the reference signal received from the base stations in the case of absence for a specific period of time of response to the first packet transmitted by these terminal devices to the base station. This shift forward in time is repeated until the maximum number of bits, depending on the size used in the system mezhdunarodnogo guard interval to achieve exact synchronization with these base stations and compensate for the delay posed by the spread signals transmitted as a wireless terminal devices and base stations.

The advantage of using this method is that between the wireless terminal devices and their base stations achieved a greater distance up to several kilometers due to the compensation of the propagation delay caused by the distance, which allows to avoid the loss of channels and information from the overlay at the time of admission. Thus it is possible to increase the range using the

A more complete explanation of the invention contains the following description of the preferred option, with reference to the drawings, in which are presented the following:

Fig.1 - schematic representation of the system, which is embodied corresponding to the present invention, the method of synchronization packets.

Fig. 2 is a block diagram of the successive States in the system when implementing relevant to the present invention the synchronization packet in the phase synchronization of the base station.

It is shown in Fig.1, the diagram illustrates a wireless communication system, in which is embodied corresponding to the invention, the method of synchronization packets to ensure the correct reception of the base stations of packets received with different delays due to propagation effects. This applies to radio access systems, providing access to mobile subscribers in a wireless network in the fixed network.

This system contains a group of base stations BS, which you can access from this system in the fixed network RF, and the group of wireless devices T. the Base station B wires are connected with the stationary RF network. Wireless Ocone the s device T are located at different distances d1, d2, d3, d4 from the respective base stations BS. In this embodiment, to increase the range of wireless systems at base stations BS use a directional antenna.

In this configuration, the system uses the European DECT standard (European digital radio), involving the use of frames mdvr of 11520 bits in duration of 10 MS with 24 channels 416,6 ISS, and twelve channels are used for transmitting and twelve for the reception. Each of the 24 channels, consisting of 480 bits, numbered from 0 to 479, includes a guard interval of 56 bits. In addition. European standard provides a valid shift clock, which can reach two binary digits.

Wireless terminal device T must synchronize their time scan time scan base stations BS before they can get service, so that the moments of transmission base stations coincided with moments of reception on the wireless terminal devices, and Vice versa, and between them is the correct data exchange.

This synchronization of wireless terminal devices is toynami, who can take the wireless terminal device T according to their synchronization are:

- No synchronization is defined as condition in which a wireless terminal device T is not synchronized at any level with any base station BS.

The pre - synchronization is defined as a condition in which a wireless terminal device T receives reference signals personnel and multiframe synchronization received from the base station BS, as well as information about its identity, but not yet synchronized with the base station,

- Synchronization state is defined as a condition in which the wireless terminal device't synced at all levels with the base station BS, that is, it has batch, personnel and multiframe synchronization.

Corresponding to the present invention, the synchronization packet is a wireless terminal device T in the condition specified above as the pre-synchronization.

In Fig. 2 shows a block diagram of the successive States in the system during the implementation of appropriate really invented the similar status standby 1, when a wireless terminal device T receives the reference signal for its time base from the base station BS, it checks the information received from the base station BS that he was given permission to communicate with the base station, at this point, the system goes to state 2 start timing at which the wireless terminal device T sends the packet to the base station BS, the System proceeds to state 3 standby response service in which a wireless terminal device T waits a predetermined time for receiving the response packet to sent the first packet. If ouchetny packet received from the base station BS, accepted wireless terminal device T within a predetermined time, the wireless terminal device T determines that it is properly synchronized with the base station BS, and the system goes to state 8 exact synchronization with the base station BS, then the wireless terminal device T enters the sync state.

In that case, if the preset period of time waiting for response package 3 expires before receiving wireless terminal device T of the response package with basic the wireless terminal device T is not guaranteed accurate by synchronizing with the base station BS, due to incorrect reception of the base station BS of the package due to the propagation delay caused by the distance from the wireless terminal device T to the base station BS

The system goes to state 5 test, in which a wireless terminal device T checks whether it can move forward the moment of sending the packet to one or more binary bits to compensate for the delay in the reception of this first package base station BS. The maximum number of binary digits to which the wireless terminal device can displace forward the send time of the packet is 54, which corresponds to midocalmom protective interval in addition to the two binary bits of the shift synchronization is allowed by the standard), and a wireless terminal device T moves forward the moment of sending the package by one binary digit each time.

In condition 5 check the wireless terminal device T checks not achieved even if the maximum number of binary digits that are valid for shifting forward; if the answer is affirmative, the system proceeds to state 6 re-transmission, in which a wireless terminal device T then moves forward in time Poselka until while the wireless terminal device T will be able to receive a response packet from the base station BS, or until it reaches the maximum number of binary digits in which it can advance the time of sending their packages.

If the wireless terminal device T reaches this maximum number of binary digits without receiving a response packet from the base station BS, the target device determines that it is at too great a distance and synchronization with the base station BS is not possible. At this point, the system goes to state 7 separation.

1. The method of synchronization data packets in a digital wireless communication systems with multiple access with time division channels between the wireless terminal device (T) and base station (BS), wherein the wireless target device (T) move forward the moment the packet relative to the signal of the reference time received from the base station (BS), if within a preset time from the base station (BS) have not received a response, wherein the wireless target device (T) move forward the moment the packet to d is orrectly way moreover, the specified synchronization state corresponds to the moment of transmission of the last packet the target device (T), on which the target device (T) received a response from the base station (BS).

2. The method according to p. 1, characterized in that the total number of binary digits to which the wireless terminal device (T) move forward the date of transfer of packets, and the maximum number of times of repetition of this displacement limit the size mezhdunarodnogo guard interval system.

3. Wireless target device (T), intended for use in digital communication systems, multiple access time division channels for communication with the base station (BS) containing means for periodically shifting ahead of time of the packet relative to the signal of the reference time received from the base station (BS), if within a preset time from the base station (BS) have not received a response, wherein the target device (T) contains a means for defining the reference synchronization state in which the target device (T) properly synchronized with the base station, and the specified oposta (T) receives a response from the base station (BS).

 

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