JP2003333663A - Software radio system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To select an optimal radio scheme at all the time in accordance with a communication environment of the site by enabling one terminal system or radio unit to be mutually extended in a plurality of CDMA communication systems. <P>SOLUTION: The software radio system has: an RF part which are shared by a plurality of radio schemes; a storage means stored with respective algorithms of the plurality of radio schemes; a reloadable logic circuit for performing signal processing of a communication by downloading a required radio algorithm; and a second storage means for storing channel capacity that each radio scheme can occupy. After the occupational channel capacities in respective radio systems are compared, a radio system capable of securing optimal occupational channel capacity is selected and the communication of user data is performed. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a code division multiple access (CDMA).
The present invention relates to a wireless communication device that performs data communication using a ple access communication method.

[0002]

2. Description of the Related Art IMT2000 (Internatio), which is being researched as a next-generation data communication system
nal Mobile Telecommunicat
Ion 2000) has decided to adopt the CDMA communication system. The IMT2000 is a third-generation wireless communication system next to the first-generation analog and second-generation digital mobile phones, and has a PHS 64 kb.
It is also compatible with high-speed data communication of 384 k which exceeds ps to a maximum of 2 Mbps.

In the IMT2000, in order to enable roaming on a global scale, standardization of a worldwide unified standard of a wireless system is in progress, but in reality, since a plurality of CDMA wireless systems are adopted, those standards are adopted. Parallel operation is planned.

In the CDMA communication system, an information signal is spread over a wide band frequency by a spreading code and then transmitted. By using different spreading codes, it is possible to secure multiple communication paths even within a common frequency band, and it is possible to improve the frequency utilization efficiency compared to the conventional narrow-band communication method. It is a method.

It is also possible to change the data communication capacity by changing the spreading processing rate, bundling a plurality of channels, or the like, so that from normal voice communication to high-speed data communication, it can be used depending on the application. You can set the communication speed.

The plurality of CDMA communication systems adopted differ in the signal processing algorithm, the signal chip rate, the occupied bandwidth, the synchronous or asynchronous of the base stations, etc., but the basic structure is common. If there is a common part in the standard of the radio frequency after the RF circuit like IMT2000, there are many parts that can be shared as the configuration of the radio device.

[0007] In a digital wireless system such as CDMA, most of the signal processing in wireless communication is performed by digital processing, so most of the configuration as a wireless device except for the RF portion that actually transmits and receives radio waves. Can be realized by a digital circuit. In this way, the wireless device, which is made into a highly logical device, can be realized in a programmable manner with respect to the parameter of the signal processing and the communication setting, and becomes a host C
It is called a software radio because it has the characteristics that the parameters can be changed arbitrarily from the PU and the radio can be upgraded by only upgrading the software.

On the other hand, current digital signal processing devices are highly integrated, and it is possible to construct a large-scale circuit having several hundreds of thousands to several millions gates in one chip. However, compared to a gate array, which is a non-rewritable digital signal processing device, a rewritable digital signal processing device, PLD (Programmab
An element such as a le Logic Device) has a relatively low integration rate to enable rewriting of logic,
In addition, since the cost per logic is high, the chip was realized by a gate array when it was mounted on the product.

However, in recent years, rewritable P
As LDs have become as large as gate arrays and cost has decreased, it has become possible not only to make prototypes but also to use them as they are in products.

[0010]

In the past, there have existed dual-mode terminals such as first and second generations of mobile phones, PHS and mobile phones, which are compatible with a plurality of wireless systems with one terminal. It was As an example, FIG. 2 shows a block diagram of a radio unit in a conventional dual mode terminal.

The antennas 201 and 202 and the RF section 20
3, 204 and the modulation / demodulation signal processing units 205, 206 are configured in accordance with the standard of each corresponding wireless system. The carrier selection unit 207 selects a modulation / demodulation signal processing unit corresponding to a predetermined wireless system at an initial stage after power is turned on. Also, when the radio system being selected becomes unusable due to deterioration of the radio wave condition, etc., a notification of line disconnection in the modulation / demodulation signal processing unit being selected is received,
Automatically change to the other wireless communication system. Alternatively, in response to a request from the application processing unit 208, a predetermined wireless system is selected when using a specific application or when connecting to a specific communication destination.

[0012] With such a configuration, when there is a clear advantage in a specific system depending on the usage situation, such as a difference in base station coverage area of each wireless communication service or a difference in data communication function, the radio wave at that point The mode is switched using items that can be set in advance, such as the method that can be received or the method that can be connected to the connection destination at a lower cost, and the mode is switched. Since it was a configuration, it was premised that there was clear selectivity in the switching decision of the dual mode.

On the other hand, in the IMT2000, a plurality of CDMA systems are operated in parallel as described above. This means that a plurality of wireless communication service networks, which do not have contact points with each other like the current mobile phone service, but have common parts in upper layers, coexist in one area. In addition, since the communication performances are similar, there is often no clear superiority that can be determined based on whether the connection is possible or can be set in advance, so that there is no clear selectivity in the dual mode switching judgment.

In addition, although the communication rate can be varied during data communication, which rate can be selected depends on how much channel capacity can be secured with respect to the total channel capacity in the area. , It becomes impossible to select the optimal communication service in advance. Therefore,
The user has to decide the communication service by his / her own judgment each time of communication.

Further, since the conventional dual mode terminals are compatible with a plurality of wireless systems, a wireless device has to be configured for each system, and the shared portion is small,
This has led to an increase in the circuit scale and power consumption of the entire terminal.

[0016]

As a means for solving the above problems, a CDMA software defined radio as described below is proposed.

An antenna section for transmitting and receiving radio waves and a plurality of Cs
An RF transceiver unit that can be shared by the DMA wireless system, and a plurality of Cs
A storage unit for storing a communication algorithm of the DMA wireless system, a logic circuit configuration unit that can be repeatedly rewritten and can perform communication signal processing according to each wireless system, and a wireless system executed in the logic circuit configuration unit can secure it. It comprises a second storage means for storing the wireless channel capacity and a comparison means for comparing the wireless channel capacity storable in each wireless system stored in the second storage means. A software defined radio system characterized in that an optimum communication system is selected and an algorithm is downloaded to the rewritable logic circuit section.

(Operation) First, the first communication algorithm is downloaded from the communication algorithm storage means to the logic circuit configuration unit. Connection procedure is performed in the communication system according to the downloaded communication algorithm,
Information on the storable communication channel capacity is acquired. The obtained channel capacity information is recorded in the channel capacity storage means, and then the second communication algorithm is downloaded from the communication algorithm storage means to the logic circuit configuration unit. Similarly, a connection procedure in the communication system is performed according to the downloaded communication algorithm, and information on the storable communication channel capacity is acquired. The obtained second channel capacity information is recorded in the channel capacity storage means.
Similarly, when the channel capacity information is recorded by the number of pre-stored algorithms, a communication system that can secure the optimum channel capacity is selected by the channel capacity comparison means, and the communication is started after downloading the algorithm again. It

[0019]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

The antenna 101 and the RF unit 102 are constructed according to a common standard. Modulation / demodulation signal processing unit 10
Reference numeral 3 is a rewritable PDL chip, and a configuration program for logical operation is downloaded from the algorithm storage unit 104 as necessary.

The algorithm storage unit 104 stores in advance a plurality of configuration programs based on algorithms corresponding to a plurality of communication systems, and an algorithm to be downloaded is selected according to an instruction from the carrier selection unit 105. In this embodiment,
It is assumed that algorithms 1 and 2 corresponding to two types of communication systems, carrier 1 and carrier 2, are stored.

The carrier selection unit 105 selects a predetermined algorithm in the initial stage after the power is turned on. In this embodiment, Algorithm 1 is selected. The channel capacity storage unit 106 stores information on the channel capacity that can be secured as a result of the line connection performed by the modulation / demodulation signal processing unit 103 according to the procedure of the communication system in the carrier 1 by the downloaded program.

After the communication channel securing procedure in Algorithm 1 is completed, the carrier selecting unit 105 subsequently gives an instruction to download Algorithm 2, and by the same procedure,
Information on the storable channel capacity of the carrier 2 is stored in the channel capacity storage unit 106.

The channel capacity comparison unit 107 compares the channel capacities that can be secured by the carriers 1 and 2 stored in the channel capacity storage unit 106, and selects a carrier according to a request from the application processing unit 108. Here, it is assumed that the one with the larger channel capacity is selected.

If the selected carrier corresponds to the algorithm 2, it is the same as the already downloaded algorithm, so the procedure directly proceeds to the user data transmission procedure according to the request from the application processing section.
If it is the algorithm 1 that corresponds to the selected carrier, the algorithm is downloaded again, and the procedure for transmitting user data is performed using the communication system of the carrier 1.

3 to 5 are flowcharts showing the procedure for selecting a communication carrier.

Immediately after the power is turned on, according to the flow of FIG.
The data of the channel capacity that can be occupied by each of the two carriers is acquired, and the carrier selection waiting state is entered. If user data communication is performed immediately thereafter, the flow proceeds to carrier selection standby 2; if the user data communication is not performed immediately and a standby state is entered, the flow proceeds to carrier selection standby 1.

In the standby state, the occupied channel capacity information is updated at regular time intervals according to the flow of FIG. 4, and when a user data communication request is made, the flow proceeds to carrier selection standby 2.

When the user data communication is started, the carrier to be communicated with is selected from the result of the comparison of the channel capacity information. If the selected result is a waiting carrier, the user data communication is started as it is and the selected result is obtained. If the carrier is different from the waiting carrier, the algorithm is downloaded and user data communication is started.

At this time, by updating the channel capacity information again, if the capacity equivalent to the channel capacity information immediately before the change cannot be occupied for some reason, it is possible to change the carrier to the other carrier again.

[0031]

By applying the present invention, a plurality of C
In a region where DMA wireless communication systems coexist, when a dual-mode terminal compatible with a plurality of CDMA wireless communication systems is realized, a dual-mode function can be realized with a circuit scale equivalent to that of a single-mode terminal. It is possible to reduce the power.

Since the communication system is selected by reflecting the availability of each communication channel every time communication is performed, a dual mode terminal which always selects a system capable of ensuring an optimum capacity can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a block diagram showing a conventional example of the present invention.

FIG. 3 is a part of a flowchart showing a procedure of carrier selection in the first embodiment of the present invention.

FIG. 4 is a part of a flowchart showing a procedure of carrier selection in the first embodiment of the present invention.

FIG. 5 is a part of a flowchart showing a procedure of carrier selection in the first embodiment of the present invention.

Claims (5)

[Claims] 1. Code division multiple access (CDMA)
(Division Multiple Access)
Regarding a communication device for performing data communication using a communication method,
A communication device capable of communicating in a plurality of CDMA wireless systems, an RF transmitting / receiving unit that can be shared in a plurality of CDMA wireless systems, a storage unit that stores a communication algorithm of the plurality of CDMA wireless systems, and rewritable and rewritable radios. And a logic circuit configuration unit capable of executing communication signal processing according to the method, selecting one from the plurality of wireless algorithms and downloading the algorithm to the rewritable logic circuit unit. The software defined radio system. 2. The software defined radio system according to claim 1, further comprising: a second storage unit that stores a radio channel capacity that can be secured by a radio system selected from the plurality of radio systems, and the second storage unit. A comparing unit for comparing the wireless channel capacities that can be secured by the respective wireless systems stored in the storing unit, and selecting the wireless system capable of securing the maximum capacity according to the result of the comparing unit, and rewriting the data. A software defined radio system characterized by downloading an algorithm to a logic circuit section. 3. The software defined radio system according to claim 1, wherein the rewritable logic circuit is selected in accordance with the result of the comparison means to select a radio system capable of ensuring a capacity suitable for an application in use. A software defined radio system characterized in that an algorithm is downloaded to the department. 4. Claims 1 and 2 and 3
Regarding the software defined radio system described in (3), when the power supply of the radio system is turned on, a radio system is selected according to the result of the comparing means, and communication is started by the radio system having the most suitable radio channel capacity that can be secured. The software defined radio system. 5. Claims 1, 2 and 3
With regard to the software defined radio system according to claim 4, in the standby mode of the radio system, selection of a radio system and download of an algorithm are periodically performed according to the result of the comparison means, and each radio system can be secured. A software defined radio system characterized by successively updating the data of the radio channel capacity.