JP2988258B2 - Mobile communication device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication device for securing a wireless communication line for a mobile object moving in a wide range.

[0002]

2. Description of the Related Art In mobile communication, a plurality of stations may simultaneously communicate in the same band. In this case, a line connection system is called a multiple access system. Among the multiple access methods, TDMA (Time Division)
On Multiple Access is time division multiple access, which is a method in which a radio frequency is time-divided, a specific time zone is assigned to a user, and communication is performed in the assigned time zone. In addition, CDMA (Code Di)
vision Multiple Access)
By using code division multiple access, the spectrum of an information signal is
This is a system for performing multiple access by spread spectrum communication in which the data is spread over a band sufficiently larger than the original information bandwidth and transmitted.

[0003] The direct spreading method is a method in which a spreading sequence code is directly multiplied to an information signal at the time of spreading.
The “me Division Duplex” is a transmission / reception same band system, also called a ping-pong system, and is a system in which the same radio frequency band is time-divided into transmission / reception for communication. The advantage of the TDD system is “micro-picocellular communication and network configuration” (Nakajima;
The 6th Karuizawa Workshop on Circuits and Systems (Apr
il 19-20, 1993 pp121-pp12
As shown in 6), it is known that transmission diversity can be applied to a base station, which is effective in reducing the size of a mobile station.

[0004] The TDMA / TDD system is PHP (Personal), a next-generation cordless telephone system in Japan.
HandyHone) system and the DECT system being developed in Europe as well. For example, P
The HP has a frame configuration as shown in FIG.
ms / 2.5ms for reception, 5.0ma for both transmission and reception
Are multiplexed into four channels with each frame as one frame.

[0005] The CDMA system is said to be a system that can achieve higher frequency utilization efficiency in a cellular system than TDMA and can accommodate more users. Direct diffusion C
In the DMA scheme, the desired transmitter is far from the receiver,
When an undesired transmitting station is nearby, the received signal of the interfering station has a higher received power than the received signal of the desired station, and the processing gain (spreading gain) alone suppresses the cross-correlation between spreading codes. The "far-far problem" in which communication with the desired station becomes impossible due to the inability to do so becomes an issue. For this reason, in a cellular system, a line (uplink) from a mobile terminal to a base station side
In, control of transmission power is essential according to the state of each transmission path.

[0006] The CDMA / TDD system is based on "Power
control in packets switch
d time division duplex di
Rect sequence spread spec
trum communication ”(R. Esm
ailzadeh M.A. Nakagawa A. kaj
iwara; Proc of VTC 92. pp98
9 to 992.1998), by transmitting and receiving signals multiplexed by direct spreading in the same frequency band, it is possible to know the state of the transmission line in the transmission frequency band from the received signal. It is possible to relatively easily perform effective power control of a transmission signal for the near-far problem which is a problem of the direct spreading CDMA. FIG. 8 shows CDMA / TD.
2 shows a frame configuration of the D system. In this system, time division is used in transmission and reception. Therefore, in cellular communication, it is necessary to synchronize transmission and reception timing not only between a mobile terminal and a base station but also between each base station. . Also, a guard time (GT) is provided to avoid collision of transmission / reception signals due to a shift in transmission / reception timing.

[0007] On the other hand, with the aim of constructing a public unified land mobile communication system (FPLMTS) of the world unified system around 2000, studies on a multiple access system of this system are being conducted mainly by the ITU. The CDMA system is a system that can achieve higher frequency utilization efficiency and accommodate more users than the TDMA system in a cellular system, and is attracting attention as a promising candidate for the FPLMTS multiple access system. 1885-2025MHz and 2110-2200MH as FPLMTS frequency bands
z has been decided, but next generation digital cordless telephone systems such as PHP system and DECT
The radio frequency band used for the system is 1.9 GHz, which partially matches the frequency band of FPLMTS. For this reason, CDs are used as a multiple access method of FPLMTS.
When the MA / TDD system is applied, it is expected that mobile terminals capable of communicating with both FPLMTS and next-generation digital cordless telephone systems using a part of the frequency band will need to be developed. From the viewpoint of cost reduction, it is desired that the system be configured so that the constituent circuits can be shared as much as possible.

In a cellular radio communication system, TDM
In the state shown in FIG. 5 where the A / TDD scheme and the CDMA / TDD scheme coexist, a mobile terminal having a configuration shown in FIG. 6 is conventionally used as a mobile terminal that can be used in both schemes. FIG. 5A shows a case where both systems are arranged in an adjacent state, and FIG. 5B shows a case where both systems are arranged in an overlapping state. As shown in FIG. And CDMA frame lengths are different from each other.

In FIG. 6, when the transmission rates of the information data of the TDMA system and the CDMA system are different, on the transmitting side, in the case of the TDMA system, the transmission data 401 that has been subjected to the voice encoding process and the like is processed by the frame assembling circuit 492. A frame is formed by adding a frame synchronization signal (UW signal) and an accompanying control signal. Next, the primary modulation circuit 403
, Digitally modulated (differential coding, PSK modulation, filtering), up-converted by a secondary modulation circuit 404, mounted on a carrier, and then transmitted by a transmission power control circuit 40.
After the power is adjusted in 6, the power is transmitted via the switch 407.

[0010] Similarly, in the case of the CDMA system, the transmission data 408 which has been subjected to the encoding process is transmitted to the frame assembling circuit 40.
9, the frame synchronization signal for the CDMA system (UW
Signal) and associated control signals are added to form a frame. Next, digital modulation (differential coding, PSK modulation, filtering) is performed by the primary modulation circuit 410, code spreading is performed by the spreading circuit 411, up-converted by the secondary modulation circuit 412, mounted on a carrier, and transmitted. After the power is adjusted by the power control circuit 406, the power is transmitted via the switch 407.

On the receiving side, in the case of the TDMA system,
The received signal is transmitted through the switch 407 and the switch 413,
The signal is down-converted and detected (quasi-synchronous detection) by the primary demodulation circuit 414 to become a baseband signal, and further processed by the secondary demodulation circuit 415 to obtain received data 416. Also, based on the result of the secondary demodulation circuit 415, the UW detection circuit 417 detects the UW signal,
The synchronization is acquired and held.

The same applies to the case of the CDMA system. The received signal is down-converted and detected (quasi-synchronous detection) by a primary demodulation circuit 419 via a switch 407 and a switch 413, and correlation is detected by a despreading circuit 402. And then 2
The next demodulation circuit 421 performs RAKE synthesis to obtain the received data 42
2 is obtained. From the result of the secondary demodulation circuit 421, U
The UW signal is detected by the W detection circuit 423 and the synchronization circuit 4
At 24, synchronization acquisition / holding is performed.

[0013]

In the above-mentioned conventional mobile band communication apparatus, since the frame lengths of both systems are different and the frame synchronization timings are relatively asynchronous, frame synchronization is established for each of them. It is necessary to perform communication by changing the transmission / reception switching timing.

Therefore, in order to perform zone switching in a state where both systems overlap or are adjacent to each other, separate UW detection circuits and synchronization circuits are required to obtain different frame synchronizations of both systems, It becomes a complicated circuit configuration.

The present invention solves such a conventional problem, and discloses a TDMA / TDD system and a CDMA / TD system.
It is an object of the present invention to provide a mobile communication device which can be used with the D system, has a mobile terminal which is miniaturized by sharing a circuit portion, and can easily perform zone switching between both systems.

[0016]

In order to achieve the above object, the present invention provides a mobile station having a base station and a mobile terminal connected to a public communication network, wherein the mobile terminal communicates while moving. A communication device, wherein the base station includes TDMA / T
Communication with a micro cell device having a predetermined zone radius for performing communication in the DD system and communication in the CDMA / TDD system;
Means for at least one of a macrocell device having a zone radius larger than that of the microcell device and having a basic transmission / reception basic claim configuration with the microcell device, and means for synchronizing a transmission / reception frame between peripheral base stations. The mobile terminal is provided with the TDMA / T
Communication means capable of performing communication in the DD system and the SDMA / TDD system is provided, and when the connection is switched from the micro cell device to the macro cell device by the movement of the mobile terminal, the micro cell Among a plurality of slots obtained by time division of the device, a throttle other than a throttle assigned to the mobile terminal, and configured to perform communication with the macro cell device according to the frequency band of the macro cell device. Is what you do.

[0017]

According to the structure of the present invention, since the transmission and reception frame lengths of the TDMA / TDD system and the CDMA / TDD system are equal, synchronization is established between both systems at a common frame synchronization timing, and the mobile terminal moves. When the connection is switched from the microcell device to the macrocell device by switching the zone, the connection is switched without taking another frame synchronization. At the time of switching the connection from the micro cell device to the macro cell device, the macro cell is controlled by the frequency band of the macro cell device with a throttle other than the throttle assigned to the mobile terminal among a plurality of slots obtained by time division of the micro cell device. Communication with the device is performed.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is an explanatory diagram showing the overall configuration of the present embodiment,
FIG. 2 is a block diagram showing the configuration of the mobile terminal of this embodiment, FIG. 3 is an explanatory diagram showing the configuration of a transmission / reception frame of a transmission channel of this embodiment, and FIG. 4 is a diagram showing the TDMA / TDD scheme and CDMA / CDMA of this embodiment. FIG. 5 is an explanatory diagram of synchronization setting of a transmission / reception frame of the TDD system, and FIG. 5 is a diagram illustrating the TDMA / TDD system and CDMA / TD.
It is explanatory drawing of the coexistence state of D system.

As shown in FIG. 1, in this embodiment, an exchange 108 and a control unit 110 are connected to a public telephone communication network 109, and the exchange 108 is provided with a macrocell having a CDMA / TDD type macrocell. System base station 1
02 is connected to the control device 110 and TDMA / TDD
Microcell system base stations 105a to 105i each having a microcell device of the system are connected, and each of the microcell system base stations 105a to 105i is provided with a wireless channel scanner 107.

Each microcell system base station 105a-
105i are communicable zones 103a to 103a, respectively.
3i, and the macro cell system base station 102 has a zone 101 having a larger zone radius than the zones 103a to 103i of the base station. The moving body 111 has a TD
A communication unit capable of performing communication in any of the MA / TDD system and the CDMA / TDD system is provided.

In this embodiment, as shown in FIG.
The A / TDD scheme has the same frame configuration as the PHP system, and the CDMA / TDD scheme uses a frame time, which is a basic frame configuration for transmission / reception, as TDMA / TD.
Each channel is multiplexed at 2.5 ms common to the D method, and a guard time (GT) is set at 0.2 ms. In the PHP system, 16 bits are used as guard bits.
Although a bit (about 42 μs) is provided, the value of 0.
The guard width of 2 ms depends on the environment in which the system is applied (mainly the zone radius), and thus does not necessarily have to be fixed. Also, this guard time is the same as in the case of PHP,
The guard bit (G) can be considered as a part of a transmission bit forming a frame.

In the present embodiment, since the transmission and reception frame lengths of both systems are equal, a base station provided with at least one system can be used not only between its own base station and peripheral base stations of the same system but also between base stations of different systems. In both cases, the transmission and reception frame timings can be synchronized with each other as shown in FIG. 4, and the mobile terminal 111 can perform communication at a common transmission and reception switching timing for both types. For this reason, it is not necessary to newly establish another frame synchronization even when zone switching is performed in a state where both systems overlap or are adjacent as shown in FIG. 5, and the circuit configuration of the UW detection circuit and the synchronization circuit Can be simplified.

In the TDMA-type microcell device, for example, when the first slot (CH1) is allocated, there is no need to perform transmission / reception in the second to fourth slots (CH2 to CH4). Therefore, it is possible to transmit and receive a signal in the frequency band of the CDMA macro cell system using this time.

For this reason, in the configuration of the mobile terminal of this embodiment shown in FIG. 2, the TDMA / TDD system and the CDMA
A part of the frequency band and the modulation / demodulation system used in the / TDD system, and the amount of information data transmitted by one channel of one of the two systems during one frame (the number of bits) is made common, so that the modulation / demodulation with the radio unit of the mobile terminal is performed. 2 (a secondary modulation circuit and a primary demodulation circuit in FIG. 2) and a part of a baseband transmission / reception data processing unit (for example, a speech codec processing unit).

In this embodiment, in the case of the TDMA system,
In FIG. 2, the switches 703 and 709 are switched to the TDMA system side by the switching signal from the system control circuit 723, and the transmission data 701 is input to the frame assembly circuit 704 via the switch 703. In the frame assembling circuit 704, a frame is formed by adding a frame synchronization signal (UW signal) and an accompanying control signal to the transmission data 701, and the obtained transmission data is connected to the frame assembling circuit 704. Next modulation circuit 70
5 is input. The transmission data is digitally modulated (differential encoding, PSK modulation, filtering) by the primary modulation circuit 705 and input to the secondary modulation circuit 710 connected to the switch 709 via the switch 709.

In the secondary modulation circuit 710, the transmission data is up-converted, loaded on a carrier and input to a transmission power control circuit 711 connected to the secondary modulation circuit 710, and after being subjected to power adjustment, The data is transmitted to the assigned slot via the switch 712. In slots other than the allocated slots, signals are transmitted and received in the frequency band of the CDMA macro cell system by switching to the CDMA circuit. As a result, it is possible to perform control for appropriately performing zone switching timing.

In the case of the CDMA system, the system control circuit 7
23, switches 703 and 709
Has been switched to the CDMA system side, and the transmission data 701 subjected to the encoding processing and the like is transmitted to the frame assembling circuit 7.
06, and a frame is formed by adding a frame synchronization signal for the CDMA system, an accompanying control signal, and the like. The transmission data having undergone the frame configuration is digitally modulated by a primary modulation circuit 707 connected to a frame assembling circuit 706 and code-spread by a spreading circuit 708 connected to the primary modulation circuit 707, and then a switch 709.
Is input to the secondary conversion circuit 710 via the.

In the following, similarly to the case of the TDMA system, the transmission data is up-converted by the secondary modulation circuit 710, loaded on a carrier and input to the transmission power control circuit 711 connected to the secondary modulation circuit 710. After the power adjustment is performed, the signal is transmitted to the assigned slot via the switch 712.

In the present embodiment, the secondary modulation circuit 710 and the transmission power control circuit 711 can have a common circuit configuration only by changing the operation clock.
In the case where the signal for frame synchronization and the accompanying control signal constituting the next modulation method and the frame are common, the frame assembling circuit and the primary modulation circuit can be shared.

On the other hand, on the receiving side, in the case of the TDMA system, the switches 714 and 720 are switched to the CDMA system by a switching signal from the system control circuit 723, and the received signal is switched from the switch 712 to the switch 712. The signal is input to a primary demodulation circuit 713 connected to 712. In the primary demodulation circuit 713, the received signal is down-converted and detected (quasi-synchronous detection) to become a baseband signal, and this baseband signal is sent to the switch 714 via the switch 714 connected to the primary demodulation circuit 713. The data is input to the connected secondary demodulation circuit 715 and processed in the secondary demodulation circuit 715 to obtain received data.

From the result of the secondary demodulation circuit 715,
UW detection circuit 716 connected to next demodulation circuit 715
The W signal is detected, and the UW signal
In the synchronization circuit 717 connected to the detection circuit 716,
Synchronization acquisition and synchronization maintenance are performed. At this time, in a slot other than the assigned slot, the circuit is switched to the CDMA circuit, and reception is performed in the frequency band of the CDMA macro cell system.

In this case, for example, by monitoring the frequency band of the CDMA system by changing the spreading code every several frames, communication with the base station via the control channel is prevented.
It is possible to estimate the number of mobile terminals accommodated in a CDMA macro cell system. As a result, the communication quality when the connection is switched to the macro cell system can be estimated, and the timing of zone switching can be determined accurately.

In the case of the CDMA system, the system control circuit 7
23, switches 714, 720
Has been switched to the CDMA side, and the received signal is
The signal is input to the primary demodulation circuit 713 via the switch 712,
The signal is down-converted and detected (quasi-synchronous detection) by the primary demodulation circuit 713, and is input to the despreading circuit 718 via the switch 714 connected to the primary demodulation circuit 713.

The received signal subjected to the correlation detection in the despreading circuit 718 is input to a secondary demodulation circuit 719 connected to the despreading circuit 718, and the secondary demodulation circuit 719 outputs RAK.
E-combining processing is performed to obtain received data 721.
Also, based on the result of the RAKE combining process in the secondary demodulation circuit 719, the UW detection circuit 7 connected to the secondary demodulation circuit 719
At 16, the UW signal is detected, and the synchronization circuit 717 connected to the UW detection circuit 716 acquires and holds the synchronization based on the UW signal. Also in this case, since the frame timings of both systems are synchronized, it is not necessary to newly establish another frame synchronization when switching to another mode at the time of zone switching or the like. The detection circuit can be shared and the circuit is simplified.

[0036]

According to the present invention, the TDMA / TDD microcell device and the CDMA / TDD macrocell device have a common transmission channel transmission / reception basic claim configuration, and By doing
When the connection is switched from the micro-cell device to the macro-cell device, the macro-cell device may be switched by the frequency band of the macro-cell device with a throttle other than the throttle assigned to the mobile terminal among a plurality of slots based on the time division of the micro-cell device. Communication is performed, the configuration of the mobile terminal is simplified, the size of the mobile terminal is significantly reduced, the production cost is advantageous, and the zone switching between both types is performed quickly and accurately.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a mobile terminal according to the embodiment;

FIG. 3 is a configuration diagram of a transmission / reception frame of a transmission channel according to the embodiment;

FIG. 4 shows a TDMA / TDD system and CDMA in the embodiment.
Configuration of Synchronous Setting of Transmit / Receive Frames in / TDD System

FIG. 5 is a configuration diagram of a coexistence state of a TDMA / TDD system and a CDMA / TDD system;

FIG. 6 is a block diagram showing a configuration of a mobile terminal of a conventional mobile communication device.

FIG. 7 is a frame configuration diagram of a PHP system.

FIG. 8 is a frame configuration diagram of the CDMA / TDD system.

FIG. 9 is a signal configuration diagram of a transmission / reception frame length in the TDMA / TDD system and the CDMA / TDD system.

[Explanation of symbols]

 704, 706 Frame assembling circuits 705, 707 Primary modulation circuit 708 Spreading circuit 710 Secondary modulation circuit 713 Primary demodulation circuit 715 Secondary demodulation circuit 718 Despreading circuit 719 Secondary demodulation circuit 723 System control circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H04B 7/26 H04Q 7/00-7/38

Claims (1)

(57) [Claims] 1. A mobile communication device comprising: a base station connected to a public communication network; and a mobile terminal, wherein the mobile terminal communicates while moving. The base station includes a TDMA / T
Communication with a micro cell device having a predetermined zone radius for performing communication in the DD system and communication in the CDMA / TDD system;
A synchronization means for synchronizing a transmission / reception frame with a peripheral base station and / or a macrocell device having a zone radius larger than that of the microcell device and having a basic transmission / reception basic claim configuration with the microcell device. Is provided, and the TDMA /
Communication means capable of performing communication in the TDD system and the SDMA / TDD system is provided, and when the connection is switched from the micro cell device to the macro cell device by the movement of the mobile terminal, the micro cell Among a plurality of slots obtained by time division of the device, a throttle other than a throttle assigned to the mobile terminal, and configured to perform communication with the macro cell device according to the frequency band of the macro cell device. Mobile communication device.