Source: http://www.google.com/patents/US20060128414?ie=ISO-8859-1&dq=6317900
Timestamp: 2014-09-18 04:04:00
Document Index: 644598806

Matched Legal Cases: ['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']

Patent US20060128414 - Wireless communication systems - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign in<nobr>Advanced Patent Search</nobr>PatentsIn 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...http://www.google.com/patents/US20060128414?utm_source=gb-gplus-sharePatent US20060128414 - Wireless communication systemsAdvanced Patent SearchPublication numberUS20060128414 A1Publication typeApplicationApplication numberUS 11/295,582Publication dateJun 15, 2006Filing dateDec 7, 2005Priority dateDec 13, 2004Publication number11295582, 295582, US 2006/0128414 A1, US 2006/128414 A1, US 20060128414 A1, US 20060128414A1, US 2006128414 A1, US 2006128414A1, US-A1-20060128414, US-A1-2006128414, US2006/0128414A1, US2006/128414A1, US20060128414 A1, US20060128414A1, US2006128414 A1, US2006128414A1InventorsMasaaki Shida, Kei Suzuki, Mikio KuwaharaOriginal AssigneeHitachi, Ltd.Export CitationBiBTeX, EndNote, RefManReferenced by (16), Classifications (9), Legal Events (1) External Links: USPTO, USPTO Assignment, EspacenetWireless communication systemsUS 20060128414 A1Abstract 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. Images(12) Claims(15)
DESCRIPTION OF THE EMBODIMENTS 1. First Embodiment 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. 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 consumption. 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 transmitted. 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.) 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. 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. 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. 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. 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 21 a and wireless part 22 a and the communication channel uses antenna 21 b and wireless part 22 b. It is acceptable to use an antenna in common and to use a splitter to make connections to multiple wireless parts. FIG. 7 is a diagram showing the operating sequence of base station 2. After activating the power supply, the base station, using wireless part 22 a and antenna 21 a, continuously outputs a signal for alerting terminal 3 to its presence on the beacon channel (CH1). Moreover, the communication channel (CH2) using wireless part 22 b and antenna 21 b 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. 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 entered again. 2. Second Embodiment 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. 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 communication. It should be further understood by those skilled in the art that although the foregoing description has been made on embodiments of the invention, the invention is not limited thereto and various changes and modifications may be made without departing from the spirit of the invention and the scope of the appended claims. Referenced byCiting PatentFiling datePublication dateApplicantTitleUS7733945May 27, 2009Jun 8, 2010On-Ramp Wireless, Inc.Spread spectrum with doppler optimizationUS7742775Jun 12, 2009Jun 22, 2010On-Ramp Wireless, Inc.Random phase multiple access system with location trackingUS7773664Dec 29, 2008Aug 10, 2010On-Ramp Wireless, Inc.Random phase multiple access system with meshingUS7782926Aug 11, 2008Aug 24, 2010On-Ramp Wireless, Inc.Random phase multiple access communication interface system and methodUS7831283Jul 30, 2007Nov 9, 2010Hitachi, Ltd.Sensor network system and sensor nodeUS7848272Nov 24, 2008Dec 7, 2010On-Ramp Wireless, Inc.Slotted mode acquisitionUS8023443Jun 3, 2008Sep 20, 2011Simmonds Precision Products, Inc.Wireless sensor systemUS8135436Mar 13, 2009Mar 13, 2012Intel Mobile Communications GmbHMobile radio communication devices and methods for controlling a mobile radio communication deviceUS8295179 *Apr 16, 2007Oct 23, 2012Fundacio Privada Centre Tecnologic De Telecomunicacions De CatalunyaMethod and system for measuring quality of networking nodesUS8717150Apr 17, 2009May 6, 2014Hochiki CorporationAlarming deviceUS20100142375 *Apr 16, 2007Jun 10, 2010Fundacio Privada Centre Technologic De Telecomunicacions De CatalunyaMethod and system for measuring quality of networking nodesDE102010015917B4 *Mar 11, 2010May 22, 2014Intel Mobile Communications GmbHMobilfunkkommunikationseinrichtungen und Verfahren zum Steuern einer MobilfunkkkommunikationseinrichtungEP2131620A1 *Apr 29, 2009Dec 9, 2009Simmonds Precision Products, Inc.Power management in a wireless sensor systemEP2290631A1 *Apr 17, 2009Mar 2, 2011Hochiki CorporationAlarming deviceWO2009062188A1 *Nov 10, 2008May 14, 2009G2 Microsystems Pty LtdReceiver napping between signalsWO2009117290A2 *Mar 11, 2009Sep 24, 2009On-Ramp Wireless, Inc.Random phase multiple access system with meshing* Cited by examinerClassifications U.S. Classification455/522International ClassificationH04B7/00Cooperative ClassificationH04W52/287, Y02B60/50, H04W52/283, H04W52/0245European ClassificationH04W52/02T4J, H04W52/28L, H04W52/28SLegal EventsDateCodeEventDescriptionDec 7, 2005ASAssignmentOwner name: HITACHI, LTD., JAPANFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:SHIDA, MASAAKI;SUZUKI, KEI;KUWAHARA, MIKIO;REEL/FRAME:017328/0377;SIGNING DATES FROM 20051006 TO 20051011RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google