U.S. patent application number 10/169764 was filed with the patent office on 2003-06-19 for communication controller for an active transponder.
Invention is credited to Saegrov, Atle.
Application Number | 20030112125 10/169764 |
Document ID | / |
Family ID | 19910701 |
Filed Date | 2003-06-19 |
United States Patent
Application |
20030112125 |
Kind Code |
A1 |
Saegrov, Atle |
June 19, 2003 |
Communication controller for an active transponder
Abstract
Method and communications controller for processing of encoded
information by a battery-powered active transponder. It is
particularly provided for the application within a transponder
system for the wireless payment of road toll, whereby the
transponder over an antenna receives modulated microwave radiation
of preset frequency for obtaining an input signal which is
demodulated for obtaining a binary input data sequence. This is
then fed to a digital processor (microcontroller) operated by a
processing clock of preset clock frequency, for decoding and
generating of a binary output data sequence, from which within a
certain duration as an answer to the received input signal an
output signal is formed, which is transmitted over the antenna of
the transponder. For reducing the load of the battery of the
transponder by the pulse-like occuring current demand of the
processor with at the same time a relative short duration between
the receiving of the input signal and the irradiating of the output
signal, the data of the decoded input data sequence are parallel
processed by the processor (17) with a relative low clock
frequency. A plurality of processor modules (19-22) of the
processor (17) which are integrated to a processing unit realizing
the parallel occuring processing of data of the decoded input data
sequence and are operated by a timing generator (symbol clock
retrieving circuit 18) with a relative low clock frequency of the
processing clock rate.
Inventors: |
Saegrov, Atle; (Trondheim,
NO) |
Correspondence
Address: |
DENNISON, SCHULTZ & DOUGHERTY
1745 JEFFERSON DAVIS HIGHWAY
ARLINGTON
VA
22202
US
|
Family ID: |
19910701 |
Appl. No.: |
10/169764 |
Filed: |
August 1, 2002 |
PCT Filed: |
January 15, 2001 |
PCT NO: |
PCT/NO01/00014 |
Current U.S.
Class: |
340/10.1 ;
340/928 |
Current CPC
Class: |
G06K 19/0701 20130101;
G07B 15/063 20130101; G06K 19/0723 20130101; G06K 7/0008
20130101 |
Class at
Publication: |
340/10.1 ;
340/928 |
International
Class: |
H04B 001/59 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 8, 2000 |
NO |
20000614 |
Claims
1. Method for processing of encoded information by a
battery-powered active transponder, which particularly is provided
for the application within a transponder system for the wireless
payment of road toll, whereby the transponder over an antenna
receives modulated microwave radiation of preset frequency for
obtaining an input signal which is demodulated for obtaining a
binary input data sequence, which then is fed to a digital
processor (microcontroller) operated by a processing clock of
preset clock frequency for decoding and generating of a binary
output data sequence, from which within a certain duration as an
answer to the received input signal an output signal is formed,
which is transmitted over the antenna of the transponder,
characterized in that for reducing the load of the battery of the
transponder by the pulse-like occuring current demand of the
processor with at the same time a relative short duration between
the receiving of the input signal and the irradiating of the output
signal data, the decoded input data sequence are processed by the
processor parallel and with a relative low clock frequency.
2. Method according to claim 1, characterized in that the parallel
occuring processing of data of the decoded input data sequence is
realized with a much lower clock frequency, preferably only a
fraction of that clock frequency, compared to a clock frequency of
about 10 MHz and higher with a serial occuring processing according
to the state-of-the-art.
3. Method according to claim 1 or 2, characterized in that the
parallel occuring processing of data of the decoded input data
sequence is realized with a clock frequency which is derived from
the clock of the symbol timing generator by retrieving of a
plurality of succeeding timing pulses of the symbol clock from the
input data sequence and which preferably corresponds to the clock
frequency of the symbol clock.
4. Method according to claim 3, characterized in that for forming
of a clock frequency either derived from the clock frequency of the
symbol clock or corresponding to this clock frequency an electronic
PLL-circuit (phase locked loop) is applied.
5. Method according to claim 1, characterized in that the parallel
occuring processing of data of the decoded input data sequence is
realized bit-by-bit.
6. Communications controller (17) for a battery-powered active
transponder, which particularly is provided for the application
within a transponder system for the wireless payment of road toll,
whereby the transponder over an antenna receives modulated
microwave radiation of preset frequency for obtaining an input
signal which is demodulated for obtaining a binary input data
sequence, which then is fed to a digital processor (17)
(microcontroller) operated by a processing clock of preset clock
frequency for decoding and generating of a binary output data
sequence, from which within a certain duration as an answer to the
received input signal an output signal is formed, which is
transmitted over the antenna of the transponder, characterized by a
plurality of processor modules (19-22) of the processor (17) which
are integrated to a processing unit realizing the parallel occuring
processing of data of the decoded input data sequence and are
operated by a timing generator (symbol clock retrieving circuit 18)
with a relative low clock frequency of the processing clock
rate.
7. Communications controller (17) according to claim 6,
characterized in that as timing generator for generating a
processing clock rate for the mentioned processor modules (19-22)
an electronic circuit is provided for retrieving the clock
frequency of the symbol clock from the input signal.
8. Communications controller (17) according to claim 7,
characterized in that for generating of a processing clock rate for
the mentioned processor modules (19-22) with a clock frequency
derived from the clock frequency of the symbol clock, preferably
corresponding to the symbol clock, a PLL-circuit (phase locked
loop) is applied.
9. Communications controller (17) according to claim 6,
characterized in that the processor modules (19-22) are dimensioned
for a bit-by-bit processing of data of the decoded input data
sequence.
Description
[0001] The invention concerns a method according to the
introductory part of claim 1 as well as a communications controller
according to the introductory part of claim 6.
BACKGROUND OF THE INVENTION
[0002] The background of the invention is the wireless payment of
charges for the use of roads (road toll) by vehicles. Systems
provided for this purpose have been delivered by the Q-Free ASA
company since many years. Nowadays these systems are used in Norway
and are well known under the term "Q-Free-box". In this connection
the term "box" is related to the module of this system attached to
an individual vehicle, that is to say to a so-called transponder.
This transponder receives data from a main station of the
transponder system and as an answer on this transmitts individual
data back to the roadside.
[0003] Meanwhile the technological development in this field has
turned to transponders which--contrary to transponders formerly
used in this field--are being operated not passive, but active and
for the operation of which microwave radiation with frequencies in
the range of 5.8 GHz is applied. With this known transponder system
the radiation received by the transponder is amplitude modulated
for the transmission of data, while the microwave radiation
transmitted by the transponder for the transmission of data is
phase modulated.
[0004] The modulated input signal obtained in the transponder by
the reception of the microwave radiation initially is demodulated
for obtaining a binary input data sequence (of an input data
frame). Then this input data sequence is fed to a digital processor
(microcontroller) operated by a processing clock of preset clock
frequency for decoding and further processing of the received data
as well as for generating of a binary output data sequence (output
data frame). During a certain duration from the output data
sequence as an answer to the input signal an output signal is
formed in the transponder, which as modulated microwave radiation
of certain frequency is irradiated over the antenna of the
microcontroller.
[0005] These active transponders are as energy source provided with
a battery. In this connection the term "battery" comprises
electrical primary cells as well as electrical secondary cells in a
single oder in a multiple arrangement.
[0006] With the known transponder systems the succeeding
transactions (transaction sequencies) between the main station of
the transponder system and the individual transponder are carried
out on the basis of an advanced communications protocol (HDLC--High
Level Data Link Control) and usually contain the processing of data
sequencies and control fields. Furthermore there is a considerable
need for the security of the transactions which are to be carried
out. To the most common security algorithms belong DES (Data
Encrypting Standard System) and Trippel-DES. However the
application of these security algorithms usually means that with
this the processing of data by the transponder becomes very time
consuming.
[0007] To this day the most common solution for a transponder of
the transponder system is a solution, with which a serial processor
is applied as microcontroller. With this solution there is
available flexibility for changes and it is possible to achieve
satisfying transaction speed with the use of processors, which
operate with a system clock rate with a clock frequency of 10 MHz
and higher.
[0008] The greatest problem which consists with microcontrollers
applied as communications controllers until now is that there from
the relatively high clock frequency of the system clock results a
relatively high load for the battery of the transponder, and this
in view of the average height and the duration of the current
(integral over the current pulses over the time withdrawn with the
frequency of the system clock) as well as in view of the fact, that
the pulse-like occuring current withdrawal represents an
exceptional load for the battery. Even if this current withdrawal
does not mean so much for the life time of the components of the
transponder, so a current withdrawal of such an extent and in an
especially pulse-like occuring way is problematical particularly at
relatively low temperatures where the internal resistance of the
battery is high.
[0009] Finally the microcontroller applied for the transponder
until now is a serially operating processor. This means that such a
processor is not ideal in view of the processing of data which can
be processed parallel, especially not then when on the one hand
processing-wise extensible actions (decoding) are necessary in the
processor and on the other hand within a shortest possible duration
after receipt of the input signal an output signal shall be emitted
from the transponder.
OBJECT
[0010] The invention has the aim on the one hand to considerably
reduce the mentioned load of the battery for extending its life
time and for improving its operability and on the other hand to
enable the transponder to emit an output signal onto the received
input signal within a relatively short duration.
INVENTION
[0011] For achieving the aforementioned aim the invention according
to the characterizing part of claim 1 and 6 respectively is
proposed.
[0012] Further advantageous and suitable procedural steps or
measures are indicated in claims 2-5 and 7-9.
[0013] On the basis of the knowledge that with the transponder
system in question the structure of the content of the data
sequences received and transmitted by the transponder at least at a
considerable amount allows a parallel and particularly bit-by-bit
occuring processing, the solution for carrying out procedural steps
according the invention indicated in claim 1 compared to the
nowadays state-of-the-art offers the advantage of a considerable
reduced load of the battery of the transponder by pulse-like
occuring current withdrawal together with a relatively short
duration until irradiation of an answer onto the received input
signal.
[0014] An advantageous feature of the invention according claim 1
is indicated in claim 2. With a parallel processing of data of the
decoded input data sequence carried out correspondingly it is
possible to realize this processing with a system clock rate with
only a fraction of the clock frequency usual until now and
nevertheless compared to the previous solution to considerable
shorten the duration between the receiving of the input signal up
till the the forming of the output signal. For that only the extent
of the processing of data of the input data sequence now occuring
has to exceed the extent of the reduction of the clock frequency in
its impact onto the mentioned duration. --For generating of such
a--compared to the state-of-the-art "slower"--processing rate a
corresponding oscillator can be applied in the transponder.
[0015] Advantageously the procedural step according to claim 3 is
applied. This solution is useful in view of the fact, that the
symbol clock is that clock within the transponder system, which has
the lowest clock frequency, namely a considerably lower clock
frequency compared to the previous system clock. The application of
a separate oscillator within the transponder for generation of the
system clock for the processor can be done without. This also has a
positive effect on the load of the battery.
[0016] By retrieving the symbol clock and the following use of it
as system clock an ideal solution for the current withdrawal from
the battery is obtained. The symbol clock is that clock with the
absolutely lowest clock frequency which can be obtained in the
transponder system without introduction of additional buffers or
the like. --A microcontroller solution, which is based on a
plurality of processor modules, which are being operated with this
system clock, enables bit-by-bit occuring decoding of the data
reaching the transponder. This forms a contrast to a
microcontroller solution, with which at first the data sequence
(the data frame) has to be stored and thereafter the processing of
the data can be started.
[0017] Claim 4 indicates a preferred solution for forming of a
clock frequency derived from the clock frequency of the symbol
clock timing generator or corresponding to this clock
frequency.
[0018] In view of the aforementioned knowledge of a processibility
of the mentioned data in a more or less parallel occuring mode
claim 5 indicates a particularly useful procedure.
[0019] The claims 6-9 concern a communications controller or useful
design of it as it can be applied with advantage in connection with
the method according to the invention.
EXAMPLES
[0020] In the following the invention will be described more
detailed with the aid of FIGS. 1 and 2 of the drawing.
[0021] FIG. 1 shows in connection with the invention an essential
part of a communications controller of a transponder according to
the state-of-the-art and as a block diagram, and
[0022] FIG. 2 shows essential parts of a communications controller
as it is applied in connection with the invention and as a block
diagram.
[0023] FIG. 1 shows a communication controller 11 of a transponder
not shown in further detail according to the state-of-the-art. The
system clock for the communications controller 1 is being delivered
by an oscillator 12. Over a line 13 incoming input data are being
stored in a receiving memory (buffer) 14. When the complete data
sequence (data frame) is being received and stored, the processor
core 15 will start the processing of the input data and prepare an
answer of the transponder onto the input data. This happens with a
system clock with a clock frequency of about 10 MHz or with a still
higher clock frequency. --After the answer is completed it will be
laid down in a transmission buffer 16, and as soon as the
transmission buffer 16 is filled with data the transmission of data
can be started and the answer can be irradiated over the antenna of
the transponder in the form of a phase modulated microwave
radiation.
[0024] FIG. 2 shows essential parts of a communications controller
17 according to the invention. This communications controller 17 is
based on a completely different "architecture" compared to the
known communications controller 1 according to FIG. 1. With the
communications controller 17 according to FIG. 2 the system clock
is delivered from a symbol clock retrieving circuit 18 which the
system clock achieved in this way delivers to all processor modules
19-22 integated for a parallel occuring processing of data.
[0025] The data decoder indicated with numeral 13 delivers decoded
data to the processor modules 19-22, which after each reception of
data over the line indicated with numeral 24 will decode these
data, process them and form answers. Immediate after the last bit
of the received data sequence (data frame) has been decoded the
transmission of answering data over the line indicated with numeral
25 can be started. In this way not only the duration between the
reception of the input signal and the irradiation of the output
signal of the transponder is considerably shortened, but--because
of the considerably reduced clock frequency of the system clock of
the transponder--also the load of the battery of the transponder is
reduced in a considerable extent.
* * * * *