Source: http://www.freshpatents.com/Wireless-communication-systems-dt20060615ptan20060128414.php
Timestamp: 2013-05-19 09:17:17
Document Index: 782700144

Matched Legal Cases: ['art 22', 'art 25', 'art 22', 'art 22', 'art 25', 'art 32', 'art 32', 'art 22', 'art 32', 'art 32', 'art 32', 'art 36', 'art 32', 'art 311', 'art 312', 'art 100', 'art 312', 'art 312', 'art 312', 'art 312', 'art 312', 'art 312', 'art 312', 'arts 22', 'art 22', 'art 22', 'art 22', 'art 22', 'art 312']

Wireless Communication Systems Inventor Store
Patents sorted by company.	06/15/06 | Class 455 Monitor | RSS | Browse: Prev - Next Wireless communication systems Abstract: In a wireless communication system having a base station and a terminal, it is important to extend the operating life of the terminal in the case of using a battery as the power supply of the terminal. Particularly in the case where a state in which a base station is not present in the range within which the terminal can communicate lasts long, the reduction of the electric power consumption during the standby of the terminal becomes an issue. The terminal monitors the received signal power strength of a signal transmitted by the base station. When the power strength exceeds a prescribed value, it is considered that the base station is present and the base station performs operations for carrying out communication with the base station. ...
Agent: Stanley P. Fisher Reed Smith LLP - Falls Church, VA, USInventors: Masaaki Shida, Kei Suzuki, Mikio KuwaharaUSPTO Applicaton #: #20060128414 - Class: 455522000 (USPTO) - 06/15/06 - Class 455 Related Patent Categories: Telecommunications, Transmitter And Receiver At Separate Stations, Plural Transmitters Or Receivers (i.e., More Than Two Stations), Central Station (e.g., Master, Etc.), To Or From Mobile Station, Transmission Power Control TechniqueThe Patent Description & Claims data below is from USPTO Patent Application 20060128414, Wireless communication systems.
[0001] The present application claims priority from Japanese application
JP 2004-359,314 filed on Dec. 13, 2004, the content of which is hereby
[0003] The present invention is an invention which is concerned with a
wireless communication system comprising a base station and a terminal
and which pertains in particular to the configuration, and the control
method therefor, of the wireless part of a terminal for implementing the
attainment of power savings during the standby of the terminal.
[0005] When it comes to conventional wireless communication systems, there
exist e.g. systems such as sensor nets and RF-ID (Radio Frequency
Identification) tags (refer to: "Sensor Networks: Evolution,
Opportunities, and Challenges", Proceedings of the IEEE, Vol. 91, No. 8
(August 2003), pp. 1247-1256). Below, an explanation regarding
conventional wireless communication systems called sensor nets and RF-ID
tags will be given by FIG. 1, FIG. 2, FIG. 3, and FIG. 4.
[0006] FIG. 1 is a diagram showing the configuration of a wireless
communication system. A system 1 comprises a base station 2 and at least
one terminal 3, base station 2 and terminal(s) 3 mutually transmitting
and receiving data and control signals by wireless communication.
[0007] FIG. 2 is a diagram showing the configuration of base station 2.
Base station 2 comprises an antenna 21, an RF part 22, a controller 23, a
memory 24, and an interface part 25. Antenna 21 is used as a wireless
signal transmitting and receiving interface with terminal 3. Signals
received via antenna 21 are demodulated in RF part 22 and processed as
received data in controller 23. In case terminal data are received from
e.g. terminal 3, they are stored as the need arises in memory 24, after
required processing has been carried out in controller 23. During
transmission, controller 23 generates a signal to be transmitted which is
modulated in RF part 22 and transmitted via antenna 21. Interface part 25
is used for connecting to a higher-level network 4.
[0008] FIG. 3 is a diagram showing an example of a configuration of a
conventional terminal 3. In the present embodiment, an explanation will
be given with a terminal used for a sensor net. Terminal 3 comprises an
antenna 31, an RF part 32, a controller 33, a memory 34, a sensor 35, and
a power supply 36. It is a terminal which has a function of communicating
the data acquired with sensor 35 to base station 2. Antenna 31 and RF
part 32 operate in the same way as antenna 21 and RF part 22 of base
station 2. Controller 33 administers the control of RF part 32, memory
34, and sensor 35 and the information from sensor 35, and transmits data
to base station 2 via RF part 32 and antenna 31. Further, in the case of
receiving control signals, etc., from base station 2 via antenna 31 and
RF part 32, it carries out various types of administration on the basis
of control information. Memory 34 is provided for temporarily storing
data acquired with sensor 35. Sensor 35 is provided for sensing
information internal and external to the terminal. There is e.g. provided
a temperature sensor which is used for a temperature monitoring system.
Power supply part 36 supplies electricity to each block of terminal 3.
[0009] FIG. 4 is a diagram showing the details of the wireless part of a
conventional terminal 3. RF part 32 has a function for modulating and
transmitting data gradually sent from controller 33 and a function for
demodulating a received signal coming from the terminal and communicating
it to controller 33 and comprises a register 313 setting the operating
parameters of these.
[0010] During transmission, data gradually sent from the controller are
encoded in an encoder 301 and up-converted in a mixer 302. The local
signal input into mixer 302 is generated by an oscillator 304. The output
signal of mixer 302 is amplified in a power amplifier 303 to a power
level required for transmission and transmitted via antenna 31. An
antenna switch 305 is used for switching between transmission and
reception circuits with respect to one antenna 31.
[0011] During reception, a signal which is input from antenna 31 is
amplified in a low-noise amplifier 306 and mixed down in a mixer 307, and
is converted to a baseband signal or an intermediate frequency (IF)
signal. Subsequently, the received signal is selected in a band pass
filter 308, amplified by means of an amplifier 309 to a signal amplitude
level considered necessary in a demodulator 310, and input in demodulator
310. The input signal is demodulated as received data in demodulator 310
and communicated to controller 33 via an interface part 311. A carrier
sense part 312 outputs the strength of the received signal.
[0012] As applications of the wireless communication system explained
above, one can e.g. cite tracking and inventory management. As far as
tracking and inventory management are concerned, the base station reading
the data of the terminal can, as the need arises, be transferred to the
vicinity or the like, not being limited to ordinarily being within the
range of communication of the terminal. Rather, the opportunities for the
terminal to be able to communicate with the base station are few, the
result being a state wherein the base station is not present most of the
time. Moreover, it is desirable that the base station, when it thinks it
wants to read out the data of the terminal, is not made to wait but is
capable of reading those data.
[0013] For battery-operated devices, as exemplified in terminals of
wireless communication systems, reductions in the electric power
consumption are important.
[0014] As an example, known in the art, of reducing the electric power
consumption of a device by utilizing the carrier sensing of the signal of
a specific channel, there is JP-A-2003-244057. As far as the system shown
in JP-A-2003-244057 is concerned, it is basically used as a system for
which it is assumed that a base station is present.
[0015] In the aforementioned RF-ID or sensor net systems, in case a
battery was used as the power supply of the terminal, an extension of the
operating life of the terminal is important from the point of view of
usefulness and operational cost reductions. In particular, in case the
terminal is not used in a state where permanent communication with the
base station is possible, there is a need for the terminal to continue
standby operation, and the electric power consumption during this standby
operation exerts a great influence on the operating life of the terminal.
As operating modes of the terminal, a mode wherein the terminal is used
continuouslyby means of exchanges of batteries and a throw-away mode can
be considered, but for whichever of the modes, an extension of the
lifetime of the terminal would contribute to a reduction in the
[0016] Generally, in the case of comparing the monitoring of received
signal demodulation and signal power, there is less power consumption
during operation, and it is also possible to make the operating time
shorter, when monitoring the signal power. Since the total electric
energy consumption is the product of the electric power consumption
during operation and the operating time, a reduction of the electric
power consumption during operation as well as a shortening of the
operating time are effective for the reduction of the total electric
[0017] Accordingly, in the present invention, the base station has
available a beacon channel for alerting the terminal to its presence and
a separate channel used for communication with the terminal. Here, a
channel is something in which a signal for alerting the terminal to the
presence of the base station and a signal used in the case of
communication between the base station and the terminal are discriminated
in at least one of a frequency domain, a time domain, and a code domain.
[0018] The terminal monitors the signal power of the frequency band of the
beacon channel of the base station and, in case the signal power of that
frequency band exceeds a predetermined prescribed value, considers the
base station to be present, and performs operations for carrying out
communication with the base station. In case the signal power of the
received signal does not exceed the predetermined prescribed value, the
terminal judges that no base station with which communication is possible
is present and goes on standby for a prescribed time. In the following,
the terminal reiterates signal strength monitoring and standby until it
has judged the base station to be present. At this point, the standby
time depends on the mode of utilization of the system, but it is
preferable for the utilization method to make it as long as can be
[0019] In the case of configuring a wireless station, particularly in
receiver systems, an electric power system separate from that of other
circuits, like e.g. the digital circuits of a demodulation system, is
made available and configured in such a way that noise of the digital
systems does not penetrate, in order for the radio frequency front end
part to be configured with analog circuits handling very minute electric
power. Because of that, by choosing a configuration wherein the function
of monitoring received signals is performed by a radio frequency analog
front end part, the configuration of the power supply and the power
supply control become simple if a power supply is supplied to the power
supply system of the radio frequency front end part and the signal
strength of the received signal can be measured.
[0020] In the case of comparing the monitoring of received signal
demodulation and signal power, there is less power consumption during
operation, and it is also possible to make the operating time shorter,
when monitoring the signal power. Since the total electric energy
consumption is the product of the electric power consumption during
operation and the operating time, a reduction of the electric power
consumption during operation as well as a shortening of the operating
time are effective for the reduction of the total electric energy
consumption. According to the present invention, it is possible, in a
wireless communication system, to reduce the electric power consumption
during the standby of a terminal, and it is possible to extend the
operating life of a battery-operated terminal. Further, according to the
present invention, the frequency of battery changes can be reduced, since
the operating life of the terminal gets extended.
[0021] The terminal intermittently performs the operation of monitoring
the power of signals transmitted by the base station and when it does not
monitor signal power, an attainment of power savings is provided for by
turning off the power supply of parts other than the control part for
performing the intermittent operation.
[0022] While the terminal is monitoring only the signal power of signals
transmitted by the base station, as for the wireless part in the
terminal, an attainment of power savings is provided for by turning on
the power only in those places which are needed for monitoring those
[0023] According to the present invention, if a power supply is provided
for the power supply system of the radio frequency analog front end part,
the signal strength of a received signal can be measured, and power
supply configuration and power supply control can be simplified.
[0024] Since the electric power consumption particularly in nearby
wireless communications generally becomes larger the case of reception
than in the case of transmission, the effect of reducing the electric
power required for reception for carrier sensing is big.
[0025] Other objects, features and advantages of the invention will become
[0026] FIG. 1 is a diagram showing a system configuration.
[0027] FIG. 2 is a diagram showing the configuration of a base station.
[0028] FIG. 3 is a diagram showing the configuration of a terminal.
[0029] FIG. 4 is a diagram showing the details of the wireless part of a
conventional terminal.
[0030] FIG. 5 is a diagram showing the details of the wireless part of a
terminal according to the present invention.
[0031] FIG. 6 is a diagram showing the configuration of a base station
[0032] FIG. 7 is a diagram showing an operating sequence of the base
[0033] FIG. 8 is a diagram showing an operating sequence of the terminal.
[0034] FIG. 9 is a diagram showing an example of a procedure for wireless
communication between the base station and the terminal.
[0035] FIG. 10 is a diagram showing another example of an operating
sequence of the terminal.
[0036] FIG. 11 is a diagram showing another example of a procedure for
wireless communication between the base station and the terminal.
[0037] In the following, the embodiments of the present invention will be
explained using the figures. The configuration of the whole system is
similar to that in FIG. 1, and the configurations of the terminal and the
base station are as shown in FIG. 5 and FIG. 6, respectively.
[0038] FIG. 5 is a diagram showing the details of the wireless part of a
terminal according to the present invention. The operation of
transmitting and receiving is similar to that of the terminal shown in
FIG. 3. The points of difference are the points of providing a power
supply management part 100 and dividing the internal parts of the
wireless part into circuit blocks 101 to 105 so as to be able to switch
the supply destinations of the power supply depending on the operating
conditions. By providing a power supply only to those circuit blocks,
from among circuit blocks 101 to 105, which are minimally required in the
operation of transmission, reception, and carrier sensing, respectively,
the wireless part is set up not to carry out unnecessary electric power
[0039] Here, carrier sensing means judging whether the base station
transmitting the beacon is present in the communication range of the
terminal, using the received power in the channel by which the beacon is
[0040] Block 105 having a register has permanent electric power supplied
while the wireless part is operating. During transmission, electric power
is supplied to circuit blocks 101, 102, 105 and during reception,
electric power is supplied to circuit blocks 102, 103, 104, 105. (If
there is no need for transmitting an ACK (Acknowledgment) signal with
respect to a received packet, there is no need to supply electric power
to circuit block 101.)
[0041] Further, during carrier sensing, an electric power supply is
provided to circuit blocks 102, 103, 105, and during reception, the
supply of electric power to block 104, for which power supply was
necessary in the conventional terminal, becomes unnecessary, so a cutback
in the electric power consumption becomes possible.
[0042] Since it is possible to selectively pick out a specific channel in
circuit block 103, if the received power of that channel is measured by
circuit block 103 during carrier sensing, it is possible to confirm the
presence of a base station with which communication is possible. There is
no need to supply electric power to circuit block 104 carrying out
demodulation and the like, so this portion of the power consumption can
be cut back. Also, it is possible to cut back the portion of the power
consumption corresponding to circuit block 101 for transmission. In a
system where the time for performing carrier sensing is long compared to
the time for performing actual data transmission and reception, even by
just partially cutting back the power consumption of the wireless part,
so the effect of extending the battery life is big.
[0043] Moreover, circuit block 103 is a reception part performing analog
signal processing and circuit block 104 is a reception part performing
digital signal processing. If a configuration is chosen wherein only
circuit block 103 is operated and the received power is measured, without
performing the signal processing of the digital system of circuit block
104, the power consumption can be reduced by cutting back the circuits
supplying electric power and by being able to shorten the operating time.
[0044] Further, in the present embodiment, the signal of the post-stage of
an amplifier 309 is input into a carrier sense part 312, but the same
effect can be obtained e.g. by a method of inputting the output of a band
pass filter 308 into carrier sense part 312 or a method of inputting the
output of a low-noise amplifier 306 directly into carrier sense part 312.
The method of inputting the signal of the post-stage of amplifier 309
into carrier sense part 312 and the method of inputting the output of a
band pass filter 308 into carrier sense part 312 have higher carrier
sensing accuracy, since the signal is input into carrier sense part 312
after filtering out other, unnecessary signals. Moreover, as for the
method of inputting the output of a low-noise amplifier 306 directly into
carrier sense part 312, it is not necessary to bring an oscillator 304, a
mixer 307, and a BPF (Band Pass Filter) 308 into operation, so an
attainment of power savings can be provided for by blocking the power
supply of the concerned blocks.
[0045] FIG. 6 is a diagram showing the configuration of a base station 2
according to the present invention. It has respective multiple antennas
21 and multiple wireless parts 22. Base station 2 has two channels
available, a beacon channel and a communication channel, and shows an
embodiment using different frequencies as different channels. In the
present embodiment, a configuration example is shown in which multiple
antennas and wireless parts are provided. This shows the configuration
for the case where different frequencies are allocated and used for the
respective channels. E.g., the beacon channel uses antenna 21a and
wireless part 22a and the communication channel uses antenna 21b and
wireless part 22b. It is acceptable to use an antenna in common and to
use a splitter to make connections to multiple wireless parts.
[0046] FIG. 7 is a diagram showing the operating sequence of base station
2. After activating the power supply, the base station, using wireless
part 22a and antenna 21a, continuously outputs a signal for alerting
terminal 3 to its presence on the beacon channel (CH1). Moreover, the
communication channel (CH2) using wireless part 22b and antenna 21b
enters a reception waiting state (S20) to wait for the reception of a
data packet from terminal 3. In case there is a received packet from
terminal 3 (S21), it is determined whether it was possible to receive
those received data without error and correctly (S22). In case it was not
possible to receive the data correctly, the received data are destroyed
and the reception waiting state is entered again (S20). Also, in case it
was possible to receive the data correctly, an Acknowledgement (ACK)
packet is transmitted toward the transmission source terminal (S23), and
so forth, to carry out normal reception processing.
[0047] FIG. 8 is a diagram showing the operating sequence of terminal 3.
FIG. 9 is a diagram showing an example of a procedure for wireless
communication between a base station and a terminal. After activating the
power supply, terminal 3 stands by during a fixed time interval (S30) and
performs carrier sensing in the beacon channel (CHl). Specifically, power
supply is provided to circuit blocks 102, 103, 105, and the signal
strength of the received signal is measured in carrier sense part 312
(S31). The relative magnitudes of the signal strength of the received
signal and a predetermined value are compared (S32). If, as a result of
the comparison, the signal strength of the received signal is less than a
threshold value, it is judged that there is no beacon and consequently
that base station 2 is not present, and there is a transfer to the
standby state (S30). If the signal strength of the received signal is
greater than the threshold value, it is judged that base station 2 is
present, power supply is provided at least to circuit blocks 101, 102,
105, the used channel is switched to the communication channel (S33), and
a data packet (P30) is transmitted (S34). After transmission of the data
packet (P30), power supply is provided to circuit blocks 102, 103, 104,
105, and an ACK packet (P21) reception waiting state is entered (S35). In
case it was not possible to receive an ACK packet (P21) even while
waiting for the fixed time interval in the ACK packet (P21) reception
waiting state (S35), the retransmission number is incremented (S36), and
if it is within a prescribed number (S37), retransmission of the same
data is attempted. In the case of receiving an ACK packet from the base
station, the data transmission is considered to have reached completion,
the retransmission counter is cleared and the standby state (S30) is
[0048] In the following, an explanation will be given, using the drawings,
of another embodiment of the present invention. FIG. 10 is a diagram
showing another example of an operating sequence of the terminal. FIG. 11
is a diagram showing another example of a procedure for wireless
communication between a base station and a terminal. It is considered
that one frequency is used in the present embodiment, base station 2
transmits the beacon signal periodically (P20), and that terminal 3
performs carrier sensing of the beacon signal (P20) of base station 2 and
measures the signal strength of the received signal.
[0049] By taking the beacon signal (P20) transmitted by base station 2 and
the timing of the carrier sensing of terminal 3 to have different
periods, it is possible to capture the beacon signal (P20) of the base
station by performing carrier sensing a number of times, in case base
station 2 is present in the range within which communication with
terminal 3 is possible. Alternatively, the time of continuously
performing carrier sensing may be made longer than the time intervals
between transmissions of the beacon signal. In the subsequent operation,
with the same method as in Embodiment 1, terminal 3 transmits a data
packet (P30) and base station 2 transmits an ACK packet (P21). According
to this embodiment, there is no need for the base station and the
terminal to switch frequency channels for carrier sensing and for data
[0050] It should be further understood by those skilled in the art that
You can also Monitor Keywords and Search for tracking patents relating to this Wireless communication systems patent application.
How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Wireless communication systems or other areas of interest.###
###Design/code © 2013 FreshContext LLC/Freshpatents.com.Patent data source: patents published by the United States Patent and Trademark Office (USPTO)Information published here is for research/educational purposes only (and in conjunction with our Keyword Monitor) and is not meant to be used in place of the full USPTO patent document/images or a comprehensive patent archive search. Complete official applications are on file at the USPTO and may contain additional data/images. FreshPatents.com is not affiliated with or endorsed by the USPTO or firms/individuals or products/designs/ideas related to listed patents and there may be applicable trademarks or servicemarks within the documents.FreshPatents.com Support - Terms & ConditionsThank you for viewing the Wireless communication systems patent info.- - - AAPL - Apple, BA - Boeing, GOOG - Google, IBM, JBL - Jabil, KO - Coca Cola, MOT - Motorla
Results in 0.37458 seconds Other interesting Freshpatents.com categories: