JP2003273773A - Apparatus and method for demodulation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small demodulator by efficiently using fingers for various use depending on a receiving state. <P>SOLUTION: A searcher 110 prepares a delay profile by using a reception signal. A controller 107 assigns a path of a high correlation value preferentially to the fingers 101 to 106 and rake apparatuses 111 to 113 on the basis of delay profile information given from the searcher 110. The fingers 101 to 106 assigned with paths perform despreading processing. A selector 108 informed that the paths are to be assigned to the rake apparatuses 111 to 113 connects the fingers 101 to 106 and the rake apparatuses 111 to 113 according to the information. The rake apparatuses 111 to 113 rake-mix the signals of the paths inputted from the selector 108. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a demodulator,
In particular, CDMA (Code Division Multi)
The present invention relates to rake reception in the triple access system.

[0002]

2. Description of the Related Art A demodulator in a code division multiple access system (CDMA), which is a third-generation mobile communication system, is good even in a multipath fading environment by rake combining desired waves arriving at respective times. It is configured so that various reception states can be obtained.

As a conventional Rake combining configuration, Japanese Laid-Open Patent Publication No.
1-8606, or JP-A-11-88247.
Japanese patent publications and the like are disclosed.

FIG. 8 shows a conventional Rake combining configuration.
In the figure, a radio unit 10 that receives a signal including two channels, performs modulation processing and converts the signal into a digital signal, and each radio unit 10 that is connected to the radio unit 10 and performs despreading processing on the output of the radio unit 10. 6 fingers (11 to 16), a searcher 19 that is connected to the radio unit 10 and creates and outputs a delay profile for each channel, and is connected to the searcher.
A controller 20 for setting timings and code numbers to fingers (11 to 16) based on the delay profile;
A rake device 17 that is connected to the fingers 11 to 13 and performs a rake combining process on the outputs of the fingers 11 to 13 to output a first demodulated signal, and is connected to the fingers 14 to 16 and outputs of the fingers 14 to 16. To the rake device 18 for performing the rake combining process and outputting the second demodulated signal.
It consists of and.

In the conventional Rake combining, first, the searcher 19
Creates a delay profile for each channel and identifies the arriving wave at each time. Then, the control device 20
In the delay profile, a path having good reception quality is selected, and the timing corresponding to the path and the code corresponding to the channel related to the delay profile are set in the finger corresponding to the channel. At this time, the maximum number of paths selected is 3 for each channel.

Next, the finger performs despreading processing on the signal output from the radio section 10 based on the set timing and code. Then, a rake device, which is pre-connected to the finger and demodulates only one channel, performs rake combining of the despread paths. At this time, the despread path has a good reception quality, so that the demodulated signal output from the rake device can be a signal having a strong error resistance.

[0007]

In the prior art, since the number of channels to be demodulated simultaneously was small,
In general, the number of paths for each channel, which is the target of despreading, is fixed. However, when the number of channels to be demodulated at the same time increases, the number of fingers required to despread each path is the product of the maximum number of channels to be received simultaneously and the maximum number of paths. It will be a major issue when it comes to realization. For example, when demodulating for 3 channels at the same time and the fingers for 3 paths are provided for each channel, the total number of required fingers is 9.

Further, in the prior art, since the number of paths associated with each channel is fixed, each finger connected to one rake device is not connected to another rake device, resulting in an inefficient structure. Met. For example, in FIG. 8, two channels are simultaneously received, and the number of fingers of each channel is three. Here, when there are four paths with good reception in the first channel and only one path with good reception in the second channel, three fingers are provided to demodulate the first channel. Used and only one finger is used to demodulate the second channel. Thus, it can be seen that one of the paths in the first channel has no fingers to allocate, while two of the fingers in the second channel remain unused and inefficient.

The present invention has been made in view of the above points, and it is possible to efficiently use a finite finger and to reduce the size of each channel without lowering the reception quality. And to provide a demodulation method.

[0010]

A demodulator of the present invention includes a wireless means for receiving data including a plurality of channels, a plurality of fingers connected to the wireless means, and a plurality of fingers connected to the wireless means. , A selector connected to the plurality of fingers, a control unit connected to the searcher for controlling the fingers and the selector based on the delay profile, and a selector connected to the selector. And a plurality of rake means that are provided.

With this configuration, the number of paths (fingers) assigned to each channel can be made variable based on the reception quality derived from the delay profile. Therefore, the fingers can be efficiently reused, and a demodulator having good reception characteristics can be realized with a smaller number of fingers.

The control means in the demodulation device of the present invention has a configuration in which at least one path for each channel is assigned to a finger.

According to this configuration, regardless of the reception quality,
Since at least one path is forcibly assigned to each channel, it is possible to reliably demodulate the channel.

The control means in the demodulation device of the present invention has a configuration in which the supply of power to the fingers not assigned and the rake means not assigned is stopped.

According to this structure, since the electric power of the finger or the rake combining means that is not allocated is not wasted, the power consumption can be reduced.

The communication terminal device of the present invention has a configuration including any one of the demodulation devices described above. Further, the base station apparatus of the present invention has a configuration including any one of the demodulation apparatuses described above.

According to these configurations, a demodulator having good reception characteristics can be realized with a small number of fingers, so that high quality wireless communication can be performed with a small device.

The demodulation method of the present invention comprises the steps of receiving data including a plurality of channels, despreading the received data, and creating a delay profile of the received data for each of the plurality of channels. Selecting the plurality of despreading outputs, controlling the despreading step and the selecting step based on delay profiles of the plurality of channels, and rake the selected plurality of signals for each channel. And a step of synthesizing.

According to this method, the number of paths (fingers) assigned to each channel can be made variable based on the reception quality derived from the delay profile. Therefore, the fingers can be efficiently reused, and a demodulator having good reception characteristics can be realized with a smaller number of fingers.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The essence of the present invention is to dynamically control the number of paths assigned to a finger and the number of fingers connected to each rake device on the basis of the reception quality of the path, thereby dynamically changing the finger and the rake device. Assign a path to
Efficient use of finite fingers.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing the configuration of a demodulation device according to an embodiment of the present invention. The demodulation device shown in FIG. 1 is installed in a communication terminal device such as a mobile phone used in a mobile communication system, for example. In the following description, the communication has already been established between the base station device and the communication terminal device, and 1 to 3
It is assumed that the following channels are transmitted from the base station device. Further, it is assumed that the communication terminal apparatus uses one searcher, six fingers for demodulating channels for the same user, and three rake apparatuses for rake combining the outputs of the fingers to simultaneously receive.

The radio section 100 performs normal radio processing on the analog signal received by the antenna, converts it into a digital signal, and outputs six fingers (fingers 101 to 1).
06) and the searcher 110. Searcher 11
0 creates a delay profile using the number of channels to be received and the spreading code of each channel notified in advance from the CPU 109, and notifies the control device 107. The information included in this delay profile is the number of arrival waves (hereinafter, paths), the arrival time of each path, the correlation value of each path, and the correspondence information of each channel and each path. The control device 107 uses a later-described algorithm based on the number of channels notified from the CPU 109 and the delay profile information notified from the searcher 110 to determine each path for each channel with a finger (one of the fingers 101 to 106), And the rake device (one of the rake devices 111 to 113).

Here, "assign a path to a finger"
Means that the control device 107 sets the delay information of the path and the spreading code for the finger.

In addition, "assigning a path to a rake device"
Means that the processing described below is repeated for the number of channels. First, the control device 107 causes the searcher 110 to operate.
Using the correspondence information of the channel and the path notified from, one channel to be the target of the one rake device that has not been allocated yet is determined. Then, the control device 107
However, the number of fingers to which each path related to the channel that is the target of the rake device is allocated is detected. Finally, the control device 107 notifies the selector 108 that the detected finger output is to be input to the rake device.

The fingers 101 to 106 to which the paths are assigned by the control device 107 simultaneously perform the despreading process by using the spreading code and delay information of the demodulation target path set by the control device 107.

The selector 108 notified that the path is assigned to the rake device controls the output of the finger to be the input of the rake device. Note that each rake device can be connected to all of the fingers.

Each of the rake devices 111 to 113 rake-combines the paths output from the target fingers, and outputs a demodulated signal for each channel.

Here, the algorithm of the CPU 109 will be described in detail using an example. 2 to 4 show examples of delay profiles for three channels created by the searcher 110. FIG. 2 is a delay profile of channel 0, where the horizontal axis represents time and the vertical axis represents the amplitude of the correlation value.
P00 is an ID that represents a path relating to channel 0 that arrived at time t00. Similarly, P01 ... P04 is t0
1 ... t04, etc., respectively.

FIGS. 3 and 4 are diagrams showing delay profiles of channel 1 and channel 2, respectively. The relationship between P and t is the same as in FIG. Of the two subscripts P and t, the subscript on the left side shows the channel number, and the subscript on the right side shows the path number. For example, P12
Represents the path 2 of channel 1.

FIG. 5 shows that the delay profile is shown in FIGS.
, The searcher 110 to the control device 1
It is a figure which shows the delay profile information notified to 07. In FIG. 5, those in which the correlation value exceeds the threshold value (here, threshold value = 50 is set) are marked with ◯ in the 7th column.

The controller 107 estimates that a signal has arrived at the time when the correlation value exceeds the threshold value and assigns the corresponding path to the finger.

Although the threshold value is fixed (50) here, it may be variable. Moreover, even if it is set for each channel, the same effects as those described below can be obtained.

Next, the operation of the controller 107 when assigning a path to a finger will be described with reference to the flow chart of FIG.

First, in step (hereinafter abbreviated as "ST") 601, a path ID relating to the maximum correlation value of each channel is detected, and a preset number N is set in descending order of the correlation value relating to the path ID. 6 fingers (101-
106).

Assuming that N is 1 and the information of FIG. 5 is processed in ST601, the path IDs relating to the maximum correlation value of each channel are P00, P10 and P21, respectively. Next, in ST602, the correlation value of each path is compared with a preset threshold value (50), and the number of paths exceeding the threshold value (hereinafter referred to as X) is detected. (In the example of FIG. 5, X = 10.)

Next, in ST603, the number of fingers is 6 to the number of paths N already set in ST601.
The value obtained by subtracting is compared with X, and when X is smaller or equal, the process proceeds to ST604. Next, in ST604, a path that has not been allocated yet is allocated to a finger that has not been allocated yet.

In the example of FIG. 5, since X> 6-3, the above processing is not performed and the following processing is performed.

If ST is larger than X in ST603, the process proceeds to ST605. ST605
In, the paths that have not yet been assigned are sequentially assigned to the fingers. In this assigning process, it is impossible to assign all the paths to the fingers, so the paths are assigned to the fingers in order of increasing correlation value.

In the example of FIG. 5, P11, P02, P
Since the correlation values are large in the order of 14, the above three paths are assigned to the fingers that have not been assigned yet. In other words, the controller 107 moves from the finger 101 to the finger 1.
Time t and code C are set for six fingers of 06 respectively.

Next, in ST606, the control device 1
07 designates fingers (101 to 1) for the selector 108.
06) and the connection information of the rake device (111 to 113).

Next, in ST607, if there is a finger or rake device that has not been assigned yet, its power is turned off.

FIG. 7 is a diagram showing an example of the finger assignment result by the controller 107. In the case of FIG. 7, the path related to channel 0 is assigned to the fingers 101 and 105. Also, the path related to channel 1 is
It is assigned to the fingers 102, 104, and 106. The path related to channel 2 is assigned to finger 103.

Therefore, the control device 107 is the rake device 1.
11 indicates that the rake device 112 is to be connected to the fingers 101 and 104.
6 and that the rake device 113 is connected to the finger 103 are notified to the selector 108.
According to the notification, the selector 108 has the fingers 101 to 101.
106 and the rake devices 111 to 113 are connected.

As described above, according to this embodiment, the number of allocated paths for each channel is made variable,
The fingers can be efficiently reused depending on the reception state, and a small demodulator can be provided.

Although the number of fingers is 6 and the number of rake devices is 3 for convenience of explanation, the number of fingers is equal to or more than the maximum number of channels to be simultaneously received, and the number of rake devices is the maximum number. .

In the above example, the reception quality detected by the searcher is the correlation value at a certain time of the path, but it may be a section average correlation value or moving average correlation value for several frames.

[0047]

As described above, the demodulation device of the present invention is in a communication state by variably controlling the number of paths assigned to fingers and the number of fingers connected to each rake device in a CDMA communication receiver. Optimal finger assignment can be performed accordingly.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a demodulation device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a first delay profile created by the searcher of the demodulation device according to the above embodiment.

FIG. 3 is a diagram showing a second delay profile created by the searcher of the demodulation device according to the above embodiment.

FIG. 4 is a diagram showing a third delay profile created by the searcher of the demodulation device according to the above embodiment.

FIG. 5 is a diagram showing delay profile information of the demodulation device according to the above embodiment.

FIG. 6 is a flowchart showing an operation when assigning fingers of the demodulation device according to the above embodiment.

FIG. 7 is a diagram showing an example of a finger assignment result by the control device according to the embodiment.

FIG. 8 is a block diagram showing a configuration of a conventional demodulation device.

[Explanation of symbols]

100 radio section 101-106 fingers 107 control device 108 selector 109 CPU 110 searcher 111-113 Lake device

Claims (6)

[Claims] 1. A wireless unit for receiving data including a plurality of channels, a plurality of fingers connected to the wireless unit, a searcher connected to the wireless unit, and creating a delay profile of the plurality of channels. A selector connected to the plurality of fingers; a control unit connected to the searcher for controlling the fingers and the selector based on the delay profile; and a plurality of rake units connected to the selector. A demodulator characterized in that. 2. The demodulator according to claim 1, wherein the control means allocates at least one path to each finger for each channel. 3. The demodulator according to claim 1, wherein the control means stops the supply of power to the unassigned fingers and the unassigned rake means. 4. A communication terminal device comprising the demodulation device according to claim 1. 5. A base station device comprising the demodulation device according to claim 1. 6. A step of receiving data including a plurality of channels, a step of despreading the received data, a step of creating a delay profile of the received data for each of the plurality of channels, and a plurality of the despreading steps. A step of selecting an output, a step of controlling the despreading step and the selecting step based on delay profiles of the plurality of channels, and a step of rake combining the selected plurality of signals for each channel, A demodulation method comprising: