JP2004363998A - Wireless communication device and wireless communication method - Google Patents

Abstract

An object of the present invention is to provide a function capable of connecting to both an ad hoc network and a mobile communication network, to avoid an increase in cost without complicating the device configuration, and to smoothly switch the network to be connected. A wireless communication device and a wireless communication method are provided.
A wireless communication device uses a TDD-CDMA system for communication with a base station of a mobile communication network. An ad hoc communication unit is provided for establishing an ad hoc network with other wireless communication devices 10 and 20 existing in the vicinity and wirelessly communicating with the other wireless communication device. This ad hoc communication means uses a TDD-CDMA system common to a mobile communication network when communicating with the other wireless communication device.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a TDD-CDMA wireless communication device and a wireless communication method using the same.
[0002]
[Prior art]
As is well known, in a mobile communication network, a mobile station is configured by a wireless communication device (User Equipment) such as a mobile phone, a personal computer, and a PDA, and data transmission between the mobile station and the base station is performed wirelessly. It has become. When voice communication or data communication is performed between the mobile stations, as shown in FIG. 4, data is exchanged via a base station (Base Station). As communication systems used for such mobile communication, for example, GSM (Global System for Mobile Communications) and WCDMA (Wideband Code Division Multiple Access) are known.
[0003]
In the mobile communication network, communication between the mobile station and the base station is bidirectional, and the communication system is a duplex system in which transmission and reception are performed simultaneously. As shown in FIG. 5, the duplex system uses an FDD (Frequency Division Duplex) that uses different frequency bands for the uplink (Uplink) from the mobile station to the base station and the downlink (Downlink) from the base station to the mobile station. ) System and a TDD (Time Division Duplex) system in which the frequency bands of the uplink and downlink are the same but the uplink and downlink are switched in a very short time. In the TDD system, one frame is divided into a plurality of (for example, 15) time slots, and each of the time slots is assigned one of an uplink and a downlink. FIG. 6 shows a TDD-CDMA (Code Division Multiple Access) frame configuration in which the TDD scheme is adopted as a duplex scheme. In the TDD-CDMA scheme, the ratio and arrangement of time slots allocated to uplink and downlink are shown. Can be appropriately set according to the traffic amount and the like (for example, see Patent Document 1).
[0004]
On the other hand, an ad hoc network is known as a wireless short-distance data communication network. In this ad hoc network, as shown in FIG. 7, it is possible to directly communicate between wireless communication devices within a radio wave reach without the intervention of a base station. For this reason, according to the ad hoc network, there is an advantage that a base station and an access point become unnecessary, and a network can be easily constructed even in a place without such communication facilities. As a communication technology for constructing such an ad hoc network, for example, Bluetooth, wireless LAN (IEEE802.11x), and the like have been proposed.
[0005]
[Patent Document 1]
JP-A-2002-232940 (paragraphs 0002 to 0008)
[0006]
[Problems to be solved by the invention]
However, in the past, different communication schemes were adopted between the ad hoc network and the mobile communication network, and when trying to realize a wireless communication apparatus that can be connected to both of those networks, the configuration of the wireless communication apparatus naturally became complicated. However, there is a problem that the cost increases correspondingly.
In addition, when switching the connection destination from one network (for example, an ad hoc network) to the other network (for example, a mobile communication network), it takes a long time for handover because both communication systems are different. There was also.
[0007]
The present invention has been made in view of such circumstances, and has a function of connecting to both an ad hoc network and a mobile communication network, but can avoid an increase in cost without complicating the device configuration. It is another object of the present invention to provide a wireless communication device and a wireless communication method capable of smoothly switching a network to be connected.
[0008]
[Means for Solving the Problems]
The invention according to claim 1 is a wireless communication device (for example, the first wireless communication device 10 or the like) that uses the TDD-CDMA system for communication with a base station of a mobile communication network, and includes another wireless communication device existing in the surroundings. Ad-hoc communication means for constructing an ad-hoc network with a wireless communication device (for example, another first wireless communication device 10, the second wireless communication device 20, etc.) and communicating with the other wireless communication device wirelessly, The communication means uses a TDD-CDMA system common to the mobile communication network when communicating with the other wireless communication device.
[0009]
Here, TDD-CDMA is CDMA using the TDD scheme as the duplex scheme. CDMA is one of the multiple access systems to which the spread spectrum system is applied, and is a communication system called code division multiple access. Examples of TDD-CDMA include TD-CDMA standardized by 3GPP (3rd Generation Partnership Project).
[0010]
As the “wireless communication device using the TDD-CDMA system for communication with a base station of a mobile communication network”, for example, a mobile phone, a PDA (Personal Digital Assistance) having a connection function with a mobile communication network, or a personal computer And other information terminals.
In addition, "other wireless communication devices existing in the vicinity" do not have, for example, a connection function with a mobile communication network, in addition to a wireless communication device having a connection function with a mobile communication network as described above. An information terminal (computer, PDA, etc.) and peripheral devices of the information terminal (eg, headset, printer, mouse, display) are also included. These wireless communication devices establish an ad hoc network with at least other wireless communication devices within a radio wave reach, and perform a function of mutually communicating between wireless communication devices in the ad hoc network (hereinafter, ad hoc communication function and ).
[0011]
According to a second aspect of the present invention, in the wireless communication apparatus according to the first aspect, the ad hoc communication means detects surrounding wireless communication apparatuses that can construct the ad hoc network, and stores information on the wireless communication apparatuses. After performing the process of acquiring from the storage unit and storing the information in the storage unit, information on the wireless communication device to be the communication partner is extracted from the information stored in the storage unit, and based on the information, the communication partner becomes the communication partner. The wireless communication device and the wireless communication device communicate with each other in the ad hoc network.
[0012]
Here, the information on the wireless communication device includes, for example, a spread code used by each wireless communication device for transmission, an identification code (ID) of each wireless communication device, and attribute information of each wireless communication device (device type, performance, Security level, etc.), and information on a communication path to each wireless communication device.
[0013]
According to a third aspect of the present invention, in the wireless communication apparatus according to the first or second aspect, the ad hoc communication unit measures an interference level based on a received signal and controls output power of transmission power based on the measured value. Is performed.
[0014]
According to a fourth aspect of the present invention, in the wireless communication apparatus according to the first or second aspect, the ad hoc communication means uses a time slot set in a downlink of mobile communication to establish a connection in the ad hoc network. It is characterized by performing communication.
[0015]
A wireless communication method according to a fifth aspect of the present invention constructs an ad hoc network by a plurality of wireless communication devices including the wireless communication device (first wireless communication device 10) according to any one of the first to fourth aspects. , Characterized in that TDD-CDMA is used for communication in the ad hoc network.
[0016]
Here, in addition to the wireless communication device according to any one of claims 1 to 4, the plurality of wireless communication devices include a wireless communication device that does not have a connection function with a mobile communication network but has an ad hoc communication function. Is also included.
[0017]
According to the invention described in any one of claims 1 to 5, a common TDD-CDMA system is used for communication in the ad hoc network and the mobile communication network, so that connection to both the ad hoc network and the mobile communication network is performed. It is possible to provide a possible wireless communication device with a simple configuration at a low cost. Moreover, according to the wireless communication device, switching of the network to be connected can be smoothly performed.
[0018]
Further, since the wireless communication devices in the ad hoc network communicate with each other, it is possible to reduce the load on the mobile communication network, thereby increasing the communication efficiency of the entire network, and The communication capacity (network capacity) can also be increased.
Further, when the radio wave does not reach the base station, another wireless communication device in the ad hoc network where the radio wave reaches the base station can be used as a relay device, and an area where connection with the mobile communication network is possible. Can be expanded as a result.
[0019]
According to the third or fourth aspect of the present invention, even if the same frequency band is used for the ad hoc network and the mobile communication network, interference is less likely to occur between the ad hoc network and the mobile communication network. , A good communication state can be ensured.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows an embodiment of an ad hoc network to which a wireless communication method according to the present invention is applied. In the figure, reference numeral 10 denotes a first wireless communication device, and reference numeral 20 denotes a second wireless communication device.
The first wireless communication device 10 is a wireless communication device (wireless communication device according to the present invention) having a function of connecting to a mobile communication network, and includes, for example, a mobile phone, a PDA, and a personal computer. The first wireless communication device 10 uses a TDD-CDMA system for communication with a base station 30 of a mobile communication network.
On the other hand, the second wireless communication device 20 is a wireless communication device that does not have a function of connecting to a mobile communication network. For example, information that is wired or wirelessly connected to a fixed communication network such as a LAN (Local Area Network) is used. It is composed of a terminal (for example, a personal computer, a workstation, etc.), a peripheral device of an information terminal (for example, a headset, a printer, a mouse) and the like.
[0021]
The first and second wireless communication devices 10 and 20 form an ad hoc network with other wireless communication devices 10 and 20 existing in the vicinity, and perform ad hoc communication between the wireless communication devices in the ad hoc network. It has a communication function, and uses a common TDD-CDMA system as a communication system in a mobile communication network. Here, in addition to the common scheme of TDD-CDMA, the used frequency band is also common.
[0022]
FIG. 2 is a block diagram illustrating a main configuration of the first wireless communication device. As shown in FIG. 2, the first wireless communication device 10 includes a transmitter 11, a receiver 12, an antenna 13, a control unit 14, and a storage unit 15.
The transmitter 11 includes a transmission data processing unit 11a that generates a transmission signal, a primary modulation unit 11b that performs primary modulation of a carrier with a transmission signal, and spread modulation (secondary modulation) of a modulation signal obtained by primary modulation with a spreading code. And an amplification unit 11d for amplifying the spread-modulated signal. That is, the transmission signal generated by the transmission data processing unit 11a is primary-modulated by the primary modulation unit 11b by a predetermined modulation method, is spread-modulated by the spreading code by the spreading unit 11c, and then transmitted to the amplification unit 11d. The signal is amplified and radiated from the antenna 13 as a radio wave.
[0023]
On the other hand, the receiver 12 includes a band filter 12a for removing unnecessary noise components included in the received signal received from the antenna 13, and a despreading unit 12b for despreading the received signal passing through the band filter 12a with a spreading code. , A demodulation unit 12c that demodulates a signal obtained by despreading, and a reception data processing unit 12d that performs various processes related to connection to an ad hoc network or a mobile communication network based on the demodulated signal. That is, the received signal received by the antenna 13 is despread by the same spreading code as that on the transmitting side after the noise component is removed by the bandpass filter 12a, and then demodulated by the demodulation unit 12c to return to the baseband waveform. It is supposed to be.
[0024]
The control unit 14 controls the transmitter 11 and the receiver 12 based on various types of information stored in the storage unit 15. The control unit 14 controls switching between transmission and reception and output control of transmission power ( Power control), and a switching process between an ad hoc network and a mobile communication network is performed. For example, when communicating with a base station 30 of a mobile communication network or another wireless communication device in an ad hoc network using a wireless line, switching between transmission and reception is performed based on a preset time slot assignment. The communication is performed by the TDD method. Further, when communicating with another wireless communication device in the ad hoc network, an interference level is detected from a reception signal input to the receiver 12, and transmission power is adjusted according to the interference level. I have.
[0025]
In the present embodiment, the transmitter 11, the receiver 12, the antenna 13, the control unit 14, the storage unit 15, and the like constitute an ad hoc communication unit according to the present invention.
On the other hand, the second wireless communication device 20 also has a transmitter, a receiver, an antenna, a control unit, and a storage unit similar to those of the first wireless communication device 10, and the other wireless communication in the ad hoc network is performed by these communication means. It is possible to communicate with the device using a wireless line.
[0026]
Next, a connection process to an ad hoc network executed by the first wireless communication device 10 having the above configuration will be described based on a flowchart of FIG.
First, in step S1, a process of switching the communication mode to the ad hoc mode is performed. This process may be automatically performed when a preset condition is satisfied, or may be performed based on a user's input operation.
[0027]
Next, in step S2, a process of acquiring information about the wireless communication devices 10 and 20 present in the vicinity is performed. Specifically, based on the received signal input to the receiver 12, it is checked whether or not the wireless communication devices 10 and 20 in the ad hoc mode are present in the vicinity, and as a result, other wireless communication devices in the ad hoc mode are checked. If the communication devices 10 and 20 exist in the vicinity, whether each of the wireless communication devices 10 and 20 has authority to connect to the ad hoc network and whether the wireless communication device 10 and 20 can connect to the ad hoc network Whether the wireless communication device is capable of constructing an ad hoc network is identified and detected from the wireless communication devices 10 and 20 in the ad hoc mode based on the determination results. After that, information about the wireless communication devices (for example, a spread code used at the time of transmission, an ID unique to the device) is stored in a storage unit such as the storage unit 15, and the process proceeds to the next step S3.
[0028]
In step S3, a process of selecting a time slot used for communication in the ad hoc network from TDD-CDMA time slots is performed. As a selection method, (1) a method of selecting only a time slot designated as a downlink (Downlink), (2) a method of selecting only a time slot designated as an uplink (Uplink), (3) an uplink , And a method of selecting from both the time slot designated for the downlink and the time slot designated for the downlink, but any method may be adopted. In this embodiment, in order to reduce mutual interference between the ad hoc network and the mobile communication network, only a time slot designated as a downlink is selected.
[0029]
In step S4, information about the wireless communication device (the first wireless communication device 10 or the second wireless communication device 20) to be a communication partner is extracted from the information stored in the storage means, and based on the information, It communicates with a wireless communication device as a communication partner via an ad hoc network. At that time, power control is performed so as not to interfere with a nearby wireless communication device that has not joined the ad hoc network. That is, the interference levels of all time slots are measured based on the received signal input to the receiver 12, and the sum of the measured value and a preset offset value (positive or negative number) is calculated as the maximum transmission power. As (allowable value), output control of transmission power is performed so as not to exceed this maximum value.
[0030]
After the connection to the ad hoc network is completed, the state of the ad hoc network is monitored until the number of wireless communication devices 10 and 20 configuring the ad hoc network reaches the upper limit (for example, 15), as in step S2 described above. The process is repeated at a predetermined cycle, and information on the wireless communication devices 10 and 20 included in the ad hoc network is updated as needed (step S5). Also, when the number of wireless communication devices forming the ad hoc network becomes “1”, the ad hoc network becomes extinct.
[0031]
In this embodiment, the control unit 14 makes a selection as to whether to use the mobile communication network or the ad hoc network when performing communication, for example, in consideration of the following elements. I have. The factors include (1) whether the wireless communication device as the communication partner exists in the ad hoc network, or (2) the wireless communication device in the ad hoc network as the communication partner communicates well with the mobile communication network or the wired network. (3) whether the call is received from outside the ad hoc network, (4) balance of communication quality and traffic volume between the mobile communication network and the ad hoc network, (5) security, (6) multicast Are included in the ad hoc network, and (7) whether the communication partner is a peripheral device such as a headset or a mouse.
[0032]
As described above, according to the present embodiment, the common TDD-CDMA system is used for communication in the ad hoc network and the mobile communication network, so that wireless communication connectable to both the ad hoc network and the mobile communication network The device 10 can be provided at a low cost with a simple configuration. Moreover, according to such a wireless communication device 10, handover between both networks can be smoothly performed.
[0033]
Further, since the wireless communication devices 10 and 20 in the ad hoc network communicate with each other, the load on the mobile communication network can be reduced, thereby increasing the communication efficiency of the entire network. In addition, the communication capacity of the network can be increased.
Further, when the radio wave does not reach the base station 30, the other wireless communication devices 10 and 20 in the ad hoc network where the radio wave reaches the base station 30 can be used as a relay device. The area that can be connected can be expanded as a result.
[0034]
In addition, even if the same frequency band is used for the ad hoc network and the mobile communication network, interference is less likely to occur between the ad hoc network and the mobile communication network. Can be secured.
[0035]
【The invention's effect】
As described above, according to the present invention, while having a function of connecting to both an ad hoc network and a mobile communication network, it is possible to avoid a cost increase without complicating the device configuration, and It is possible to provide a wireless communication device and a wireless communication method capable of smoothly switching a network to be connected.
[0036]
In addition, even if the same frequency band is used for the ad hoc network and the mobile communication network, interference is less likely to occur between the ad hoc network and the mobile communication network. Can be secured.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an embodiment of an ad hoc network to which a wireless communication method according to the present invention is applied.
FIG. 2 is a block diagram showing a configuration of a main part of the first wireless communication device of FIG. 1;
FIG. 3 is a flowchart illustrating a process of connecting to the ad hoc network of FIG. 1;
FIG. 4 is a schematic configuration diagram illustrating an example of a mobile communication network.
FIG. 5 is a schematic diagram for explaining a TDD system and an FDD system.
FIG. 6 is a diagram illustrating an example of a TDD-CDMA frame configuration.
FIG. 7 is a schematic configuration diagram illustrating an example of an ad hoc network.
[Explanation of symbols]
10 First wireless communication device 20 Second wireless communication device 30 Base station

Claims (5)

A wireless communication device using a TDD-CDMA system for communication with a base station of a mobile communication network,
Ad-hoc communication means for constructing an ad-hoc network with other wireless communication devices existing in the vicinity and communicating with the other wireless communication device wirelessly, the ad-hoc communication means is provided for communication with the other wireless communication device. And a wireless communication apparatus using a TDD-CDMA system common to the mobile communication network. The ad hoc communication unit detects a surrounding wireless communication device capable of constructing the ad hoc network, acquires information on the wireless communication device from each of the wireless communication devices, stores the information in the storage unit, and stores the information in the storage unit. Extracting information about the wireless communication device to be a communication partner from the received information, and performing mutual communication with the wireless communication device to be the communication partner in the ad hoc network based on the information. The wireless communication device according to claim 1, wherein: 3. The wireless communication according to claim 1, wherein the ad hoc communication unit measures an interference level based on a received signal, and controls output power of transmission power based on the measured value. apparatus. 3. The wireless communication system according to claim 1, wherein the ad hoc communication means performs communication in the ad hoc network using a time slot set in a downlink of mobile communication. Communication device. A wireless communication method comprising: constructing an ad hoc network by a plurality of wireless communication devices including the wireless communication device according to claim 1; and using a TDD-CDMA system for communication in the ad hoc network.

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