Method for collision-free data exchange between reading/writing device and mobile data carrier, reading/writing device and identification system

The invention relates to a method for collision-free data transmission between at least two read / write devices, (SLG) and at least one mobile data memory (MDS), particularly in an identification system with at least one attached to objects mobile data memory (MDS) for detecting object-related status and / or process data eg at a dispatch, transport and / or manufacturing system the individual objects.

In a data transfer according to the prior art between a plurality of read / write devices (SLG) and at least one mobile data memory (MDS) can with simultaneous identification a mobile data memory (MDS) by several Read / write devices (SLG) a collision occur, which communication prevents. To avoid such Collision, the individual read / write devices (SLG) far linked and such a synchronized, that at any given time only a single write / read device (SLG) is active. The non-activated read / write devices (SLG) are not available in this period for communication purposes to disposal.

The invention is based on the object, a method of collision-free data transmission between at least two Read / write devices (SLG) and at least one mobile data memory (MDS) offering. In addition to a read / write device (SLG), a mobile data memory (MDS) and / or a available identification system for such a method will.

The object is for the method by the features of patent claim 1 dissolved. be Advantageous process variants described in the dependent claims 2- eighth For the read / write unit (SLG), the object is achieved by the features of patent claim 9, for the mobile data memory (MDS) by the features of claim 10 and for the identification system solved by the features of patent claim 11.

In the method for collision-free data transmission according to the invention between at least two read / write devices, (SLG) and at least one mobile data memory (MDS) is a transmission channel with at least one time slot with at least two register areas, said the register areas according to a random identification numbers assigned to the requesting read / write devices (SLG) will.

Of the read / write devices (SLG) emitted identification numbers are now the mobile data memory (MDS) received in the register areas. The single ones Register spaces within the timeslot consecutively arranged so that any successfully received an identification number in a first register field recognition the transmitted identification number and thus the associated Read / write device (SLG) by the mobile data memory (MDS) occurs.

After detection of an identification number that is assigned Read / write device (SLG) by the mobile data memory (MDS) is selected to establish a communication link.

According to an advantageous variant of the method in data transmission a transmission channel with two time slots each with three register fields. This provides six registers areas available, so that a total of six identification numbers each register areas can be mapped to a statistically collision-free Data transmission between a mobile data memory (MDS) and a total of six read / write devices (SLG) can take place.

In an intended communication with a higher number of read / write devices (SLG) has a corresponding Number to be kept by the register ranges.

Advantageously, the identification numbers of the Read / write devices (SLG) received coded possible realize many register areas in the mentioned time slots to.

When randomly allocating the individual identification numbers interrogating the read / write devices (SLG) to each provided for the purpose of registration areas Transmission channel, the per se known Aloha procedure be used. By such random can in each newly launched communications cycle, the allocation of Identification numbers for each register areas newly be regulated to the individual read / write devices (SLG) also an approximately equal opportunity to communicate with the mobile data memory (MDS) grant.

The transmission channel has a further (subsequent) Time slot in which the mobile data memory (MDS) upon detection of and selecting a received identification number a read / write device (SLG) the received identification number the selected read / write device (SLG) to the requesting read / write devices (SLG) sends back to These tell that the queried read / write devices (SLG) for communication from the mobile data memory (MDS) has been selected.

The individual read / write devices (SLG) which receive the mobile data memory (MDS) returned (coded) ID number and comparing it to the own Identification Number. If they match, the respective determine read / write device (SLG) that it from the mobile Data memory (MDS) has been selected for communication and can with the actual communication after the collision-free start detection by the mobile data memory (MDS).

At the same time those read / write devices (SLG), the identification number from the mobile data memory (MDS) has not been selected, notice that a communication at the moment with the selected mobile data memory (MDS) is not possible and, if necessary at a later time again a renewed attempt at identification are started can.

The inventive method can in principle a transmission method Use according to ISO 18000-4-MOD 3 method the modifications described invention be made. For this to known per se and widespread method used and the collision-free Data transmission will be further developed according to the invention.

The inventive read / write device (SLG), which according to the invention Mobile data memory (MDS) according to the invention and Identification system used to apply the described Inventive process and can thus be used used performing a collision-free data transmission will.

The invention is based on embodiments in the Drawings explained. Show it:<dl tsize="5" compact="compact"><dt>1 shows</dt><dd>a schematic representation of a data transmission between two read / write devices (SLG) and a mobile data memory (MDS), and </dd><dt>FIG 2</dt><dd>a schematic representation of the transmission channel for transmitting data over time.</dd></dl>

1 shows write / read devices SLG1 and SLG2 which a Communication with a mobile data storage MDS aspire. For this SLG1 and SLG2 send their identification numbers to the ISO-18000-4-MOD3 process necessarily simultaneously Timeslot SID1 to the mobile data memory MDS. Thus finds an inevitable collision instead.

At the moment the MDS but a communication wishes alone with SLG1, while communication with SLG2 in undesirable is (dashed arrow).

For data transfer between SLG1, SLG2 and MDS are in FIG 2 the respective transmission channels of SLG1, SLG2 and MDS ready. The transmission channels have identical Timeslots SID and register areas RB, initially both SLG1 and SGL2 their respective identification numbers (1) and (2) in the time slot SID1 send it to the MDS and MDS in the time slot SID1 by simultaneous arrival of Notes identification numbers of SLG1 and SLG2 collision ( "SID1: collision") and neither SLG1 still clearly SLG2 can identify. Thus, no communication established will.

According to the invention, the transmission channel used two more timeslots SID2 that according to FIG 2, the three register areas RB1-3 and RB have 4 -6. This register areas RB by a random (eg the Aloha procedure) for receiving the identification numbers (1) and (2) the here involved SLG1 and SLG2 prepared. When shown Procedure is register area RB2 for receiving the Identification number (1) of SLG1 and register area RB4 for receiving the identification number (2) of SLG2 provided.

According send SLG1 and SLG2 their identification numbers again at the MDS, in the time slots SID2.

The identification number (1) of SLG1 is in register area received RB2 and the identification number (2) of SLG2 in registers RB 4. Since register area RB2 time previously arranged as a register area RB4 in the transmission channel is a recognition of SLG1 is determined by the MDS.

In a later timeslot CO-CH is then the MDS received in the register area RB2 identification number (1) at SLG1 and SLG2 particular coded returned. in the SLG1 is by comparison with the own identification number found that SLG1 been selected for communication has been. In SLG2 is by comparing and finding a Non-compliance with the own identification number found that SLG2 actually not for communication was selected.

The following now takes a (further not shown) data transfer between SLG1 and MDS instead. SLG1 could collision the MDS by applying the invention are selected method for further communication.

In analogy and modification of the ISO-18000-4-MOD3 process corresponding timeslot SID1 a time slot S1 of ISO-18000-4-MOD3 process corresponding to time slots SID2 time slots R1 of the ISO-18000-4-MOD3 process and corresponding timeslot CO-CH a time slot R2 of the ISO-18000-4-MOD 3 method.