DE10300495B4 - Method for controlling the data flow in WAP-based transmissions - Google Patents

Abstract

Method for controlling the data flow in WAP-based transmissions over a wireless connection,
(a) taking decisions on the type of transmission based on short-term and long-term predictions about the quality of the wireless connection,
b) making long-term predictions about the possibility of setting up the wireless connection or the quality of the wireless connection in the form of send and / or get or suspend or resume,
c) where short-term predictions regarding the quality of an existing wireless connection are made with regard to:
cl) the number of asynchronous transactions and / or
c2) delaying retransmission and / or
c3) a change of the burst mode and / or
c4) the package size.

Description

Territory of invention

The The invention relates to a method for controlling the data flow in WAP-based transmissions over one wireless connection. Here, the quality and the flow are predicted, then by a parameterization the exchange of information to optimize.

WAP is a protocol stack that is optimized for mobile communication. This Stack is used in most current GSM or GPRS applications from mobile devices used; in the future there will also be a use of the stack for UMTS applications provided, an application in other environments would be too conceivable. At least that's the case Europe too. WAP is not just a protocol, it encompasses all Layer, from the application layer to layer 2. This is what the WAP stack has five layers, all protocols being specified by a forum. The protocol specializes in transmission of data between mobile terminals and the mobile network. So there are different standards, WAP 1.0 and WAP 2.0. It can meanwhile IETF protocols for transmission and the session control can be used. A WAP connection exists between a client and a gateway, with other services like the internet but also other services.

So There is WAE (Wireless Application Environment), the interactions between WAP / WEB applications and wireless devices that a WAP browser.

Farther there is the WSP (Wireless Session Protocol), the http similar functionality implemented and added new features like a very long lasting session realized and implemented Suspend and Resume functionality. Farther is it responsible for to send and receive information (Send) and (Get). With Help from Suspend and Resume can still maintain a connection or be interrupted at short notice, depending on how the situation it requires. This has the advantage that the data does not recur have to be sent that have already been sent.

One Another protocol is the WTP (Wireless Transaction Protocol). This is a very simple transaction-oriented one Protocol that can be used to implement clients (mobile devices) and that efficiently over wireless packet-oriented networks works. This protocol is responsible for transaction management, retransmission, removal of Duplicates, Actuations, Connections and separations of packets, segmentation and reassembly of packages. The functionalities are comparable to TCP. It is, however, geared to connections, the higher one Have error rates. So there is no TTL (No Time To Live). It gives different transaction classes, retransmissions for confirmation and selective retransmissions, selective acknowledgments and asynchronous transactions, flexible confirmations (HOLD) and moving ones Transaction window. These are just a few of the features of this protocol.

In the publication GB 2 351 874A An arrangement for transmitting and receiving data packets over a radio-based communication network is described. The object of the described arrangement is to utilize the available radio resources more effectively. This is done by adjusting the packet size in the TCP layer so that the lower-level (RLC) blocks that have a fixed size are used optimally. On the basis of the predicted amount of data, if necessary, the base station can be requested to provide the client with a different transmission bandwidth (high speed link or low speed link).

The DE 197 30 159 A1 sets forth a communication method and system for transmitting data that is divided into a plurality of data packets and transmitted between at least two communication units using a communication network. The method and system make it possible to determine data packets or groups of data packets lost during a transmission due to temporary interruptions of the communication link established via the communication network, based on information received from the communication network. It allows to transfer these packets or groups of packets at a later time.

The Document WO 01/73972 A1 describes a method for controlling the transmission of data packets between the transceivers of a on the basis of radio cells organized mobile network. It will as the transmission power and the available transmission frequencies a base station for the transfer from data packets to different clients optimally to the operational Conditions in the communication network can be adjusted.

The object of the invention is to influence the reliable protocol WAP to that effect and improve re-transmissions and thereby increase throughput. Hereby, the quality of the wireless connection and cell change must be considered.

These The object is achieved by the inventions having the features of the independent claims. advantageous Further developments of the inventions are characterized in the subclaims.

abstract seen, is a procedure based on calculations, the the future quality determine the wireless connection as well as future cell changes, Decisions are made on the different levels of the WAP protocol be implemented.

in this connection On the one hand, short-term forecasts are made that are about fundamental ones Decisions such as setting up a wireless connection or sending and receiving data.

Shorter-term Predictions serve to change some parameters associated with the transmission of packages.

Especially it is a method of controlling the data flow in WAP-based transmissions over one wireless connection, being based on short-term and long-term predictions about the quality the wireless connection decisions about the type of transmission to be hit. For long-term predictions about the possibility of building the wireless connection or the quality the wireless connection will make decisions in the form of send and / or Get hit or suspend or resume.

at Decisions about Sending and receiving (SEND and GET) become basic choices whether data should be received or sent should. As a rule, such a starting point is flexible.

The Commands SUSPEND and RESUME park a wireless connection or let them revive. Corresponding commands are z. From the ftp protocol known. Should z. For example, the short-term forecasts are enormous Predict deterioration and the long-term predictions also, so the wireless connection can be parked. Should be an improvement the short-term and long-term forecasts, so does the compound started again.

• – die Anzahl der asynchronen Transaktionen und/oder
• – das Verzögern einer erneuten Übertragung und/oder
• – eine Veränderung des Burstmodus und/oder
• – die Paketgröße.

For short-term predictions about the quality of an existing wireless connection, a decision is made about:

• - the number of asynchronous transactions and / or
• Delaying retransmission and / or
• A change of the burst mode and / or
• - the package size.

Should z. For example, in a future, the quality below a certain value fall, so can the transfer delayed a package become. In particular, it may be delayed if confirmation of the Package does not have to be sent in a timely manner or has arrived. Especially with retransmissions, it is advantageous to determine an interval with a counter. This is how WAP becomes an interval with a counter certainly, counting down becomes. Should be a retransmission be necessary, so will the counter or the interval is increased and counted down again. In dependence the quality can the interval be increased or be downsized. If a very good quality can be predicted then that is It is advantageous to resend packages quickly. When falling below one certain quality should be a longer one Interval selected become.

So can depend on from the quality the wireless connection the number of parallel transactions changed become.

By a large number of small package transactions are increasing the overhead of control information versus payload, however, decreases the error rate per package. Furthermore, it may be necessary for some Applications that run in parallel on the terminal, the number of concurrent increase asynchronous transactions.

at the adaptation of the burstrate are sent a variety of packets, which are confirmed by a message from the recipient. It will be here not every single package confirms but only a sequence. If packages are missing, then the Number of missing packets communicated. Should be a wireless connection a good quality have, then the Burstrate can be increased become. Can be excluded due to the prediction of packet loss, will be the next Package group (the next burst) urgently sent to unnecessary Avoid waiting times and increase data throughput. Should A packet loss will be foreseen, this behavior will again reset and sending the next Bursts performed in normal mode.

Furthermore, it is possible to influence the packet size. With only one package, there is a greater chance that errors will occur. This can only be increased if a good quality is available or expected. Furthermore, in a foreseen cell change the package length selected so that the transmission of the packet in the old cell can be completed completely. The transaction of the next packet then waits until the cell change has taken place.

One Cell change can always be predicted if the signal strength of a Cell decreases and the signal strengths of other surrounding cells increase. Thus, a prediction based on the Course of the signal strengths possible.

The The quality prediction method preferably uses one multidimensional stochastic algorithm, in particular covariance matrices, neural networks, genetic algorithms and / or simulated annealing used. Here are time-dependent statements about the quality or upcoming Cell change calculated.

In the calculation will flow in the case of GSM / GPRS, preferably the received signal code power (RSCP), the position, the direction, the altitude, the speed, the received signal strength indicator (RSSI), the block size, the Codec, the header compression method, SNR, traffic volume, the transmission delay, the block error rate, the bit error rate or carrier to interference ratio (C / I), power control commands, with the outputs be determined. It should be noted that these influencing factors none right to completeness to have. It is also conceivable to carry out weighting by means of tax codes, which flow into the algorithm. Farther Is it possible, the quality to incorporate the uplinks and downlinks in a specific ratio. In the case of UMTS, analogue quantities are used for the calculation.

One Another component of the present invention is a mobile terminal in the form of a PDA or a GSM / GPRS / UMTS mobile, with resources and their equipment, which allow the sequence of a method according to the method claims. In general, these devices have one or more microprocessors which are controlled by software. This software implemented the process, in particular the method of prediction the quality and on the other hand, the method by which adjustments are made on the basis of Predictions are made. The software does not necessarily have to only be implemented on a microprocessor; a logical division on several microprocessors, which are also different devices (for example, mobile phones and PDAs), is possible, too.

in the The invention will be explained in more detail below with reference to exemplary embodiments which are shown schematically in the figures. Same reference numbers in the individual figures designate the same elements. In detail shows:

1 the schematic structure of the WAP stack in version 1.x;

2 the schematic structure of the WAP stack in version 2.x with integrated 1.x stack;

3 a table of parameters that can be part of the WAP stack and their property on the transfer.

in the The following are examples of short / long Time predictions described.

in the first example is predicted that the carrier to interference Ratio (C / I) at the time when the transmission is expected the next Packages will take place, will be significantly deteriorated to afterwards to be at a very low level again. In this case would be with worked on short-term parameters (send package late, Shrink package groups ...). In the opposite case (in the short term everything very good, after that comes a big one disorder one that lasts long) is tried in the short term, if possible much to transfer (Variety of transactions, large package groups), then on time Use long-time parameters (eg the connection "parking" via SUSPEND).

One another example of Long Short time is that you know that at the moment CIR is good, but from other information (send power close to the maximum allowed power ...) can be concluded that the terminal is on the edge the cell is very good and thus the quality of the connection soon will be bad. Again, the data is being tried fast to send.

An example of Packet Group / Number asynchronous transmissions (number of transactions and package groups):
The number of packets that can be optimally sent at a given time is constant and known (given by available bandwidth and link quality). It is now free to choose how this number should be split.

Case A: either fewer asynchronous transmissions (transmissions) and larger groups of packets or
Case B: more asynchronous transmits and smaller package groups

When a big message is sent Should a particular action have higher priorities then Case A will be considered. For this connection, the largest possible package group is to be formed.

If, on the other hand, several equal amounts of data are to be transmitted, an attempt is made to transmit all equivalents in parallel, ie case B. The table in 3 On the one hand, shows the parameters that can be changed by the process by being directly controlled. Other parameters are not changed or controlled indirectly. Furthermore, it can be seen to which layer of the layer model the commands are assigned. The table shows in a further column which effect they have and whether they can be directly influenced by the present method. So it can be seen from the fifth column, which influence they have on the transmission.

Claims (13)

Method for controlling the data flow in WAP-based transmissions via a wireless connection, a) being based on short-term and long-term predictions about the quality the wireless connection decisions about the type of transmission to be hit, b) where long - term forecasts of the possibility the construction of the wireless connection or the quality of the wireless Connection decisions in the form of Send and / or Get or Suspend or Resume to be taken c) where short-term forecasts in terms of quality made an existing wireless connection decisions are regarding: cl) the number of asynchronous transactions and / or c2) of delaying a retransmission and / or c3) a change the burst mode and / or c4) the package size. Method according to the preceding claim, characterized that even with a prediction about an imminent cell change adjusted the package size is to stop the transfer before the cell change and with the next Package to wait for the completed cell change. Method according to one of the preceding claims, characterized characterized in that, in a prediction, a packet loss in the transmission excludes the next Packet group (burst) is forced to send a continuous data transfer to ensure and to minimize breaks. Method according to one of the preceding claims, characterized characterized in that in a prediction of a falling below a certain quality the connection a delay the transmission and / or retransmission a package is made until the quality increases. Method according to one of the preceding claims, characterized in that in a prediction over a Below a certain quality, the package size is reduced becomes. Method according to one of the preceding claims, thereby in that in a prediction of a falling below a certain quality the number of parallel transactions is changed, - in which especially the number increased will and the size of the packages is reduced. Method according to one of the preceding claims, characterized characterized in that in a prediction of exceeding a certain quality, the Burstrate elevated becomes. Method according to one of the preceding claims, characterized characterized in that the method for the prediction of qualities multidimensional stochastic algorithm, in particular Covariance matrices, neural networks, genetic algorithms and / or used simulated annealing. Method according to the preceding claim, characterized characterized in that the algorithm is time dependent statements about quality calculated. Method according to one of the preceding claims, characterized characterized in that in the calculation the received signal code power (RSCP), the position, the direction, the altitude, the speed, the received signal strength indicator (RSSI), the block size, the Codec, the header compression method, SNR, traffic volume, the transmission delay, the block error rate, the bit error rate and / or carrier to interference ratio (C / I) and considered as output become. Mobile terminal computer system, characterized by means and their establishment, the procedure of a procedure allow according to one of the preceding method claims. Software for a mobile device, having a WAP stack, characterized in that the software is a method according to one of the preceding method claims performed can. disk for a mobile terminal, characterized by the storage of software after the previous one Software claim.