JP2002111548A - Radio receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the power consumption concerning path search, without causing reception quality to deteriorate. SOLUTION: A correlator 4 makes the path search window width changeable, according to an instruction from a path search controller 8. This controller 8 determines the delay value of a path, having a maximum delay from a peak level, based on information on a path stable 7, sets to change the path search window width, based on the delay value, and instructs the correlator 4 to make this change.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio receiving apparatus for performing direct spread spectrum spread communication, and more particularly to a process for monitoring a path.

[0002]

2. Description of the Related Art As a communication system excellent in noise and interference characteristics, there is a direct spread type spread spectrum communication system. In this communication system, communication is performed by spreading an information signal with a spreading code having a band much wider than that of the information signal.

[0003] In wireless communication, the path of a radio wave on a transmission path (hereinafter referred to as a path) is reflected, diffracted, and reflected by buildings and the like.
Various paths are followed by the transmission, so that the arrival times of the paths to the receiver are different.

In the case of a direct spread spectrum spread communication system, signals arriving via such different paths can be individually separated. Therefore, RAKE reception for improving reception quality by combining these signals is proposed. Is generally performed. For this RAKE reception, it is necessary to know the timing of various paths, the signal strength, and the like, and a path search is performed for that purpose.

The path search is a process of gradually changing the timing of a spread code to be multiplied by a received signal, measuring the correlation value at each timing, and determining the timing of some paths having larger correlation values. This path search is performed only within the path search window width centered on the timing of the currently received main path.

The path search window width and the path search cycle are
The values are fixedly set so that a sufficient path search can always be performed.

[0007] For this reason, an unnecessary path search may be performed depending on the conditions, and the power consumption is wasted. Therefore, if the path search window width is reduced or the path search cycle is lengthened to prioritize reduction of power consumption, only insufficient path search results can be obtained depending on conditions, and satisfactory reception quality cannot be obtained. There was a defect.

[0008]

As described above, conventionally,
Since the path search conditions such as the path search window width and the path search cycle are uniform, there is a problem that power consumption increases or reception quality deteriorates.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a wireless communication apparatus capable of reducing the power consumption related to the path search without deteriorating the reception quality. A receiving device is provided.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a radio receiving apparatus for performing direct spread spectrum spread communication, wherein a predetermined path centered on a phase of a main path captured is provided. A path search for a phase within a search window width is performed at predetermined timings, and at least one of the path search window width and the timing interval for performing the path search can be changed. And (1) the amount of delay from the peak level path for the maximum delay path that has been delayed the most from the peak level path detected in the past path search.

(2) Delay spread obtained from past path search results.

(3) Spread gain.

(4) Moving speed.

A path search control unit such as a path search control unit for changing and setting at least one of the path search window width and the timing interval used by the path search unit based on any of the above. .

According to another aspect of the present invention, in a radio receiving apparatus for performing direct spread spectrum spread communication, a path search for a phase within a predetermined path search window width centered on the phase of a captured main path is performed. It is performed at every predetermined timing, and is capable of changing at least one of the path search window width and the timing interval, for example, a path search means including a correlator, a signal power integrator and a path search unit, and a multipath. A surrounding environment recognizing unit such as a path search control unit for recognizing a surrounding environment to be generated; and the path search window width and the path search used by the path searching unit based on the surrounding environment recognized by the surrounding environment recognizing unit. To change and set at least one of the timing intervals to perform And a over switch control means.

By taking these measures, the width of the path search window and the interval between the timings of performing the path search are changed according to the communication conditions. It is possible to extend the interval of the timing for performing the search, and it is possible to reduce the execution frequency of the path search.

According to another aspect of the present invention, in a radio receiving apparatus for performing direct spread spectrum spread communication, a path search for a phase within a predetermined path search window width centered on the phase of a captured main path is performed. For example, a path search means including a correlator, a signal power integrator, and a path search unit, and a search for only n paths whose transmission path response values are indicated in a path table, for example, a correlator, a signal power integration Path maintenance means for performing path maintenance comprising a device and a path search unit, and a ratio of a path whose correlation output level is equal to or less than a predetermined threshold value among the n paths indicated in the path table is equal to or less than a predetermined reference ratio. An example in which the path maintenance is repeatedly performed without performing the path search until the path ratio becomes equal to or smaller than the reference ratio is performed. And a path search control unit such as a path search control unit.

By taking such a measure, the reliability of the path table is determined as the ratio of the paths whose correlation output level is equal to or less than a predetermined threshold value among the n paths indicated in the path table. If the reliability of the path table is equal to or more than a certain value, path maintenance is performed. Therefore, the execution frequency of the path search is reduced.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a main configuration of a radio receiving apparatus according to each embodiment of the present invention. Note that FIG. 3 shows only the configuration of a part related to the path search.

As shown in FIG. 1, the radio receiving apparatus according to each embodiment of the present invention includes an antenna 1, a high-frequency circuit (hereinafter, RF).
2, an A / D conversion unit 3, a correlator 4, a signal power integrator 5, a path search unit 6, a path table 7, a path search control unit 8, and a high-order control unit 9.

The spread signal received from antenna 1 is R
After being frequency-converted by the F-circuit 2, it is sampled by the A / D converter 3 to be a received baseband signal.

The correlator 4 has a spreading code for performing synchronization acquisition as a tap coefficient, despreads the received baseband signal, and outputs a correlation value. When a path search window width or a path search cycle is designated by the path search control unit 8, the correlator 4 performs despreading for the path search under the conditions.

The signal power integrator 5 integrates the correlation output power value from the correlator 4 over a certain period.

The path search section 6 takes in the output from the signal power integrator 5 together with the phase in the path slot, and detects the phase in the path slot of the path having a large correlation output. The path search unit 6 further adds power to the output of the signal power integrator 5 and detects the phase in the path slot of the path having a relatively high level using the result of the despread output for a relatively long time. The path table 7 is updated based on.

The path search control unit 8 obtains predetermined information for each embodiment described later, changes the path search conditions according to the conditions, and notifies the correlator 4 of the path search conditions. I do.

Next, the operation of some embodiments having the above-described common configuration and partially different processing will be described.

(First Embodiment) Hereinafter, a first embodiment will be described.

First, in this embodiment, the correlator 4 operates according to a procedure as shown in FIG.

That is, when the correlator 4 is started by turning on the power, the second timer and the first timer are reset (steps ST1 and ST2).
Here, the first timer and the second timer are built in the correlator 4, and the first timer has a prescribed path search cycle, and the second timer has a prescribed several times or more the path search cycle. The forced search cycle is counted.

Next, the correlator 4 waits for the first timer to expire (step ST3). And the first
If the timer has expired, the correlator 4 checks whether the second timer has expired (step ST4).

If the second timer has not expired, the correlator 4 executes a path search with the path search window width specified by the path search control unit 8 (step ST5). This path search is a well-known process, except that the path search window width is changed and set to a value designated by the path search control unit 8. Then, when the correlator 4 performs the path search, the signal power integrator 5 and the path search unit 6 operate as is well known, and the path table 7 is updated.

As shown in FIG. 3, the path search control unit 8 waits for the update of the path table (step ST11). Therefore, when the path table is updated as described above, the path search control unit 8 exits from the standby state accordingly, and calculates the maximum delay amount based on the updated path table information ( Step ST12). The maximum delay amount is a delay amount of a path having the maximum delay amount from the peak level path.

Subsequently, the path search control unit 8 checks whether or not the absolute value of the maximum delay amount is within the threshold value n [chip] (step ST13). If the absolute value of the maximum delay amount is within the threshold value n [chip], the path search control unit 8 sets the path search window width to be used in the next path search to ± n _max [chip]. (Step ST1
4). However, the absolute value of the maximum delay is equal to the threshold n
If not less than [chip], the path search control unit 8 sets the path search window width to a specified maximum width ± N [chip] (step ST15). However, n <N, and the absolute value of the maximum delay amount is substituted for n _max .

Then, the path search control unit 8 determines in step S
The path search window width set in T14 or step ST15 is notified to the correlator 4 (step ST1).
6). Thereafter, the path search control unit 8 determines in step ST1
It returns to the standby state of 1.

After executing the path search in step ST5, the correlator 4 receives the designation of the path search window width from the path search control unit 8 performed as described above.
The designated path search window width is registered as the path search window width for the next path search (step ST6).

As described above, the path search window width used by the correlator 4 is set such that each time the information of the path table 7 is updated by one execution of the path search, the maximum delay amount indicated by the updated information is obtained. ± n _max [chip] or ± N
Changed to [chip]. Further, the specific numerical value of ± n _max [chip] is changed and set according to the absolute value of the maximum delay amount.

However, when it is determined in step ST4 that the second timer has expired when the first timer has expired, the correlator 4 changes the path search window width from the path search control unit 8 Maximum width ± N ignoring specification
Execute a path search as [chip] (step ST
7). After that, the correlator 4 accepts the designation of the path search window width from the path search control unit 8 performed as described above, and uses the designated path search window width in the path search for the next path search. It is registered as a window width (step ST8). Thereafter, the path search control unit 8 returns to the standby state of step ST11.

In this way, every time the second timer expires, that is, in the forced search period, the path search is forcibly executed with the path search window width being the maximum width ± N [chip].

As described above, according to the present embodiment, the correlator 4 repeatedly performs a path search at a specified path search cycle, but the path search window width used in each path search has an absolute value of the maximum delay amount. The value is changed and set to ± n _max [chip] or ± N [chip] based on the value. That is, usually ±
A path search is performed with a path search window width of N [chips]. When the maximum delay amount is small, the path search window width is ± n.
_max [chip]. By reducing the width of the path search window in this way, the period for executing the path search is shortened, so that power consumption is reduced. When the maximum delay amount is small, it is considered that there is no large delay path in an environment where a path with a large timing deviation from the current main path is unlikely to occur. A path search based on quality can be performed, and the reception quality does not decrease.

Moreover, in this embodiment, ± n _max [chip]
The specific numerical value of is also changed according to the absolute value of the maximum delay amount, so that the path search window width can be reduced to a minimum within a range that does not reduce the reception quality, and the power consumption can be reduced efficiently. Becomes possible.

Further, according to the present embodiment, in the forced search period, the path search is always performed with the path search window width being the maximum width ± N [chips]. Even if a path deviates from the narrowed path search window width, such a path can be correctly detected without being missed forever.

(Second Embodiment) Next, a second embodiment will be described.

In the second embodiment, the correlator 4 operates in the same procedure as in the first embodiment. That is, the correlator 4 repeatedly performs a path search at a specified path search cycle, but the path search window width used in each path search can be changed to a value designated by the path search control unit 8.

The second embodiment differs from the first embodiment in the procedure of setting the path search window width in the path search control unit 8.

That is, in the present embodiment, as shown in FIG. 4, the path search control unit 8 waits for the update of the path table (step ST21). Then, when the path table is updated, the path search control unit 8 exits from the standby state accordingly and calculates the delay spread based on the updated path table information (step ST22).

Subsequently, the path search controller 8 checks whether or not the delay spread is within the threshold value s [μs] (step ST23). If the delay spread is within the threshold value s [μs], the path search control unit 8
The path search window width to be used for the next path search is ±
n _spread [chip] is set (step ST24). However, if the delay spread is equal to or greater than threshold value s [μs], path search control unit 8 sets the path search window width to a specified maximum width ± N [chip] (step ST2).
5). However, n _spread <N.

Then, the path search control unit 8 determines in step S
The path search window width set in T24 or step ST25 is notified to the correlator 4 (step ST26).
Thereafter, the path search control unit 8 returns to the standby state of step ST21.

As described above, the path search window width used by the correlator 4 is set to be equal to the delay spread indicated by the updated information every time the information in the path table 7 is updated by one execution of the path search. The value is changed and set to ± n _spread [chip] or ± N [chip] based on this.

As described above, according to the present embodiment, the correlator 4 repeatedly performs a path search at a specified path search cycle. The path search window width used in each path search is determined based on the delay spread. Change to ± n _spread [chip] or ± N [chip]. That is, usually ± N
The path search is performed with the path search window width of [chip]. When the delay spread is small, the path search window width is reduced to ± n _spread [chip]. Since the path search window is narrowed in this way, the period during which the path search is executed is shortened, so that power consumption is reduced. When the delay spread is small, it is considered that the environment where the phase spread of the multipath is small and the path whose timing is largely shifted from the current main path is unlikely to occur, so that even a narrow path search window width is sufficient. The path search can be performed quickly, and the reception quality does not decrease.

(Third Embodiment) Next, a third embodiment will be described.

In the third embodiment, the correlator 4 operates in the same procedure as in the first embodiment. That is, the correlator 4 repeatedly performs a path search at a specified path search cycle, but the path search window width used in each path search can be changed to a value designated by the path search control unit 8.

The second embodiment differs from the first embodiment in the procedure for setting the path search window width in the path search control unit 8.

That is, in this embodiment, as shown in FIG. 5, the path search control unit 8 waits for the update of the path table (step ST31). Then, when the path table is updated, the path search control unit 8 exits from the standby state accordingly and acquires the spreading gain information from the upper control unit 9 (step ST3).
2).

Subsequently, the path search control unit 8 checks whether or not the spreading gain indicated in the obtained spreading gain information is M ₁₆ [chip] (step ST33). If the spreading gain is M ₁₆ [chip], the path search control unit 8
Sets the path search window width to be used in the next path search to ± n ₁₆ [chip] (step ST34). However, if the spreading gain is not M ₁₆ [chip],
That path search control unit 8 if spreading gain is M _{25 6} [chip] is the maximum width ± N of defining a path search window width
[Chip] is set (step ST35). Where n
₁₆ <N.

Then, the path search control unit 8 determines in step S
The path search window width set in T34 or step ST35 is notified to the correlator 4 (step ST36).
Thereafter, the path search control unit 8 returns to the standby state of step ST31.

As described above, the path search window width used in the correlator 4 is set to ± n ₁₆ [chip] or ± N [chip] based on the spreading gain every time one path search is executed. Changes are set.

As described above, according to the present embodiment, the correlator 4 repeatedly performs a path search at a specified path search cycle. The path search window width used in each path search is determined based on the delay spread. ± n ₁₆ [chip] or ±
Change and set to N [chip]. That is, the spreading gain is M
_{When 256} [chip] is sufficiently secured, ± N [chi
The path search is performed with the path search window width of [p], but if the spreading gain is kept as small as M ₁₆ [chip], the path search window width is narrowed to ± n ₁₆ [chip]. Since the path search window is narrowed in this way, the period during which the path search is executed is shortened, so that power consumption is reduced. When the spreading gain is as large as M ₂₅₆ [chip], the dynamic range of the delay profile is wide, so that it is possible to detect a path with a large delay time, that is, a path with a low reception level. By setting, it is possible to improve the accuracy of path detection. However, when the spreading gain is as small as M ₁₆ [chip], the reception level of a path having a large delay time is extremely low, and it is difficult to detect. Even with a narrow path search window width, the accuracy of the path search does not change, and the reception quality does not decrease.

(Fourth Embodiment) Next, a fourth embodiment will be described.

In the fourth embodiment, the correlator 4 operates in the same procedure as in the first embodiment. That is, the correlator 4 repeatedly performs a path search at a specified path search cycle, but the path search window width used in each path search can be changed to a value designated by the path search control unit 8.

The second embodiment differs from the first embodiment in the procedure for setting the path search window width in the path search control unit 8.

That is, in the present embodiment, as shown in FIG. 6, the path search control unit 8 waits for the update of the path table (step ST41). Then, when the path table is updated, the path search control unit 8 exits from the standby state accordingly and acquires the moving speed information from the upper control unit 9 (step ST4).
2). This moving speed information indicates the current moving speed of the own device.

Subsequently, the path search control unit 8 checks whether or not the moving speed indicated by the obtained moving speed information is equal to or higher than K [km / h] (step ST43). If the moving speed is equal to or higher than K [km / h], the path search control unit 8 sets a path search window width to be used in the next path search to ± n _upperK [chip] (step ST44). However, the moving speed is K [km / h]
If it is less than the above, the path search control unit 8 sets the path search window width to a specified maximum width ± N [chip] (step S).
T45). However, n _upperK <N.

Then, the path search control unit 8 determines in step S
The path search window width set in T44 or step ST45 is notified to the correlator 4 (step ST46).
Thereafter, the path search control unit 8 returns to the standby state of step ST41.

As described above, the path search window width used in the correlator 4 is set to ± n _upperK [chip] or ± N [chi] based on the moving speed every time one path search is executed.
p].

As described above, according to the present embodiment, the correlator 4 repeatedly performs a path search at a prescribed path search cycle. The path search window width used in each path search is determined based on the moving speed. ± n _upperK [chip] or ± N
Change to [chip]. That is, the moving speed is K [k
m / h], the path search is performed with a path search window width of ± N [chip], but the moving speed is K [km].
/ H] or more, the path search window width is ± n _upperK
[Chip]. Since the path search window is narrowed in this way, the period during which the path search is executed is shortened, so that power consumption is reduced. If the moving speed is slow, the duration of the path is long as a whole, so that it is possible to improve the accuracy of path detection by setting a wide path search window width. It is expected that the frequency of occurrence / disappearance is high, and it is not necessary to search for a large delay path with a short path duration even under normal conditions. Nor.

(Fifth Embodiment) Next, a fifth embodiment will be described.

In this embodiment, the correlator 4 operates according to the procedure shown in FIG.

[0069] That is, when the correlator 4 is activated by such power-on, is set to a predetermined value t _s as counting value to the first timer (step ST51). Subsequently, the correlator 4 resets the second timer and the first timer, respectively (step ST52 and step ST53). Here the first
The timer and the second timer are built in the correlator 4, and the first timer uses a set time value that can change the time value, and the second timer uses a standard path search. The forced search period specified at least several times the period is counted. In the present embodiment, the timing value is set to the first timer, three predetermined values of T _s <T _M <T _L the relationship is selectively set. That is, initially, the time value of the first timer is set to the minimum value T _S.

Subsequently, the correlator 4 waits for the expiration of the first timer (step ST54). Then, if the time of the first timer has expired, the correlator 4 checks whether or not the time of the second timer has expired (step ST55).

Here, if the second timer has not expired, the correlator 4 executes a path search with the path search window width designated by the path search control unit 8 (step ST56). This path search is a well-known process, except that the path search window width is changed and set to a value designated by the path search control unit 8. Then, when the correlator 4 performs the path search, the signal power integrator 5 and the path search unit 6 operate as is well known, and the path table 7 is updated.

As shown in FIG. 8, the path search control unit 8 waits for the update of the path table (step ST71). Accordingly, if the path table is updated as described above, the path search control unit 8 exits from the standby state accordingly and recognizes the delay profile pattern based on the updated path table information (step S1). ST72).

The state of occurrence of the multipath greatly depends on the surrounding environment where the wireless receiving apparatus is placed, and generally, the delay profile pattern shows a characteristic pattern according to the surrounding environment.

In the case of a mountainous area, a large delay path arrives due to reflection from surrounding mountains and the like, and shows a delay profile pattern as shown in FIG. 9, for example. And in this case,
Since there is no shield such as a building near the terminal, the path itself hardly disappears as shown in FIG.

In the case of an open land, since there are no reflected objects in the surrounding area, there are very few delayed waves, and only direct waves are present. For example, a delay profile pattern as shown in FIG. 10 is shown. And even in such an environment, it is expected that the frequency of disappearance of the path is low as shown in FIG.

In the case of a suburb, a large delay path such as a mountain does not exist, but a medium delay path reflecting from a large building slightly away exists, so that, for example, a delay profile pattern as shown in FIG. 11 is shown. Also, when moving at high speed, for example, as shown in FIG. 11, it is expected that the frequency of occurrence and disappearance of a path due to shadowing is high.

In the case of an urban area, the number of passes is large but the delay time is very short because there are many high-rise buildings in the surrounding area. For example, a delay profile pattern as shown in FIG. 12 is shown. Further, since there are many reflective objects, the frequency of occurrence and disappearance of the path is very high as shown in FIG.

Therefore, based on such a property, the path search control unit 8 recognizes any of the delay profile patterns recognized in step ST72 as “mountain area type”, “open area type”, “suburban type”, or “city area type”. Is determined (steps ST73 to ST75).

If the delay profile pattern is “mountain zone type”, the path search control unit 8 sets the path search window width to the specified maximum width ± N [chip] and sets the path search cycle to the maximum value t. _L (step ST
76).

If the delay profile pattern is “open ground type”, the path search control unit 8 sets the path search window width to ± n _S [chip] and sets the path search cycle to the maximum value t _L. (Step ST77).

If the delay profile pattern is “suburban type”, the path search control unit 8 sets the path search window width to ± n _M [chip] and sets the path search cycle to the maximum value t _S. (Step ST78).

If the delay profile pattern is not any of "mountain zone type", "open land type" and "suburban type", that is, if it is "city area type", the path search control unit 8 sets the path search window width. Is set to ± n _S [chip], and the path search cycle is set to the maximum value t _S (step ST79).

The path search window width set here is
The relationship is set as n _S <n _M <N.

Then, the path search control unit 8 determines in step S
The path search window width set in any of T75 to ST79 is notified to the correlator 4 (step S75).
T80). After that, the path search control unit 8 returns to the standby state of step ST71.

After performing the path search in step ST56, the correlator 4 receives the path search window width and the path search cycle from the path search control unit 8 performed as described above. The path search window width and the path search cycle are registered as the path search window width and the path search cycle for the next path search (step ST57). Thereafter, the path search control unit 8 sets the first timer value to the path search cycle accepted in step ST57, and then repeats the processing from step ST53.

As described above, every time the information of the path table 7 is updated by one execution of the path search, based on the pattern of the delay profile indicated by the updated information, that is, based on the surrounding environment, The path search window width used in the correlator 4 is ± n _S [chip], n _M [chip], N
[Path], and the path search cycle is changed and set to one of T _s , T _M , and _TL .

However, when it is determined in step ST55 that the second timer has expired when the first timer has expired, the correlator 4 changes the path search window width from the path search control unit 8. Maximum width ± ignoring specification
Execute a path search as N [chip] (step S
T59). Thereafter, the correlator 4 accepts the specification of the path search window width and the path search cycle from the path search control unit 8 performed as described above, and determines the specified path search window width and path search cycle in the next time. Are registered as the path search window width and the path search cycle in the path search (step ST60). After that, the path search control unit 8 sets the first timer value to the path search cycle received in step ST60, and repeats the processing from step ST52.

In this way, every time the second timer times out, that is, in the forced search cycle, the path search is forcibly executed with the path search window width being the maximum width ± N [chip].

As described above, according to the present embodiment, the path search window width is set large and the path search cycle is set large in the mountainous area. Since a large delay path exists in the mountainous area, such a large delay path can be detected without missing by maintaining a large path search window width, and good reception quality can be maintained. In a mountainous area, since the path itself does not disappear much, a sufficient path search can be performed even if the path search cycle is set to be large, and the reception quality does not decrease.

In an open land, since there are very few delayed waves and only direct waves are present, a sufficient path search can be performed even if the path search window width is set to be small, and the reception quality does not deteriorate. Absent. In an open area, the frequency of path disappearance is low, so that a sufficient path search can be performed even if the path search cycle is set to be large, and the reception quality does not decrease.

In the suburbs, since there is a medium delay path, by setting the path search window width to a medium width, such a medium delay path can be detected without missing and good reception quality can be maintained. In the suburbs, the frequency of occurrence and disappearance of paths is high, but the path search cycle is set small, so that it is possible to detect the latest correct path in response to such frequent changes of paths, Good reception quality can be maintained.

In an urban area, since a large number of paths having very short delay times occur, a sufficient path search can be performed even if the path search window width is set small, and the reception quality does not deteriorate. . In urban areas, the frequency of path occurrence / disappearance is extremely high, but the path search cycle is set to a small value so that the latest correct path can be detected in response to such frequent changes in paths. Thus, good reception quality can be maintained.

As described above, the path search period is shortened by reducing the path search window width and extending the path search cycle within a range in which good reception quality can be maintained in any environment. Therefore, power consumption is reduced.

(Sixth Embodiment) Next, a sixth embodiment will be described.

In this embodiment, the correlator 4 is set to ± N
[Chip] path search In addition to the path search for the window width,
A search for only the path timing on the path table 7 (hereinafter referred to as path maintenance) can be performed. Whether to perform the path search or the path maintenance is determined according to an instruction from the path search control unit 8.

In this embodiment, the correlator 4
It operates according to the procedure shown in FIG.

That is, when the correlator 4 is started by turning on the power or the like, the second timer and the first timer are reset (steps ST81 and ST8).
2). Here, the first timer and the second timer correspond to the correlator 4
The first timer counts a specified search cycle, and the second timer counts a forced search cycle specified several times or more of the search cycle.

Subsequently, correlator 4 waits for the first timer to expire (step ST83). Then, when the first timer has expired, the correlator 4 checks whether the second timer has expired (step ST84).

If the second timer has not expired, the correlator 4 checks whether or not a path search request described later has been made from the path search control unit 8 (step ST85). It should be noted that the path search request is sent after the previous path search or path maintenance is performed.
The correlator 4 registers and holds the information when a path search request is made. Therefore, here, the correlator 4 confirms whether or not the fact that the path search request is made is registered and held.

If no path search request has been made, correlator 4 executes path maintenance (step ST86). If path search has been requested, or if the second timer has expired, correlator 4 performs the path maintenance. Performs a path search (step ST89). When the correlator 4 performs the path search or the path maintenance, the signal power integrator 5 and the path search unit 6 operate as known,
The path table 7 is updated.

As shown in FIG. 14, the path search control unit 8 waits for the update of the path table (step ST101). Accordingly, when the path table is updated as described above, the path search control unit 8 exits from the standby state accordingly, and determines the total number p of the paths registered in the updated path table and their paths. Among them, the number of low-level paths whose correlation output level is equal to or less than a predetermined threshold α is determined (step ST1).
02).

Subsequently, the path search control unit 8 checks whether or not the ratio q / p of the number q of low-level paths to the total number p of paths registered in the path table is equal to or larger than a specified value P (step S1). ST103). Only when the ratio q / p is equal to or greater than the specified value P, the path search control unit 8 requests the correlator 4 to execute a path search at the next search timing (step ST104).

After the path search request is made as described above, or if the ratio q / p is less than the specified value P, the path search control unit 8 returns to the standby state of step ST101.

After performing the path maintenance or the path search in step ST86 or ST89, the correlator 4 confirms whether or not the path search request from the path search control unit 8 is made as described above. (Step ST87 or Step ST90). Then, when a path search request is made, that fact is registered and held (step ST88 or step ST91), and thereafter, the processing after step ST82 or after step ST81 is repeated. If the path search request has not been made, step ST82 and subsequent steps or step ST
The processing after 81 is repeated.

As described above, the correlator 4 performs either the path search or the path maintenance at a predetermined search cycle. The path search or the path maintenance is performed by executing the path search or the path maintenance. Is updated, the number q of low-level paths in the total number p of paths registered in the updated path table 7
Is set based on the ratio q / p.

However, each time the second timer times out, that is, in the forced search period, the path search is forcibly executed.

As described above, according to the present embodiment, path maintenance is performed as long as the ratio q / p of the number q of low-level paths in the total number p of paths registered in the path table is less than the specified value P. , Power consumption is reduced. As described above, when the ratio q / p is less than the specified value P, the reliability of the previous path search result is high, so that the path can be sufficiently detected by the path maintenance, and the reception quality does not deteriorate. When the ratio q / p becomes equal to or more than the specified value P and the reliability of the previous path search result is reduced, or when the path search is performed in the forced search cycle, the path search is performed even if the path occurrence status changes. Can be detected without missing out, and good reception quality can be maintained.

In the case of the present embodiment, the threshold value α and the specified value P may be fixed, or may be changed according to the spreading gain, peak level / interference / noise level.

In the case of changing by the spread gain, when the spread gain is large, the dynamic range of the delay profile is large, so that it is expected that a path with a low level can be detected, so that the threshold α can be set low. Further, since the reception can be performed relatively stably, the specified value P can be set low. As a result, the frequency of the path search decreases, and the power consumption can be further reduced.

When changing according to the peak level / interference / noise level, the results are as shown in FIGS.
The threshold alpha ₁ [Peak Level-beta _1], the threshold alpha ₂ is set to Interference plus Noise Level + β _{2], α 1,} and the threshold to select the higher alpha _2. Then, when the peak level is high, α ₁ > α _{2 as} shown in FIG. 15A, and α ₁ is selected as the threshold value. When the peak level is low, α ₁ <α _{2 as} shown in FIG. 15B, and α ₂ is selected as the threshold value. As a result, the threshold can be adaptively controlled.

Regarding the specified value P, when the peak level is high, the reception environment is good. Therefore, it is preferable to reduce the specified value P and, as a result, reduce the path search frequency to reduce the power consumption.

(Seventh Embodiment) Next, a seventh embodiment will be described.

FIG. 16 is a diagram schematically showing how the assignment of the path search window width by the path search control unit 8 in this embodiment changes.

As shown in this figure, in this embodiment, the path search control unit 8 sets the path search window width to the maximum value ± N [chip] at a rate of once every four times, and passes the remaining three times. Set the search window width to ± n _min [chip]. Note that n _min <N
It is.

In this way, the path search processing time can be reduced, and as a result, power consumption can be reduced.

(Eighth Embodiment) Next, an eighth embodiment will be described.

In the eighth embodiment, the correlator 4 operates in the same procedure as in the first embodiment. That is, the correlator 4 repeatedly performs a path search at a specified path search cycle, but the path search window width used in each path search can be changed to a value designated by the path search control unit 8.

The second embodiment differs from the first embodiment in the procedure for setting the path search window width in the path search control unit 8.

That is, in the present embodiment, as shown in FIG. 17, the path search control unit 8 waits for the update of the path table (step ST111). Therefore, if the path table is updated as described above,
The path search control unit 8 gets out of the standby state accordingly, and calculates the maximum delay amount based on the updated information in the path table (step ST112). The maximum delay amount is a delay amount of a path having the maximum delay amount from the peak level path.

Subsequently, the path search control unit 8 sets the path search window width to be used in the next path search to ± n _max [chi
p] (step ST113). Note that the absolute value of the maximum delay amount calculated in step ST112 is substituted for n _max .

Then, the path search control unit 8 determines in step S
The path search window width set in T113 is notified to the correlator 4 (step ST114). Thereafter, the path search control unit 8 returns to the standby state of step ST111.

As described above, the path search window width used by the correlator 4 is set such that each time the information of the path table 7 is updated by one execution of the path search, the maximum delay amount indicated by the updated information is obtained. The value is changed and set based on ± n _max
Set to [chip]. However, when the second timer has expired, the correlator 4 ignores the path search window width by the maximum width ± N [chi
p].

As described above, according to the present embodiment, the path search is performed with the path search window width being the maximum width ± N [chip] at a rate of once every several times as in the above-described seventh embodiment. ,
Otherwise, a path search with a path search window width of ± n _max [chip], that is, a path search with a narrow path search window width, is performed. In the present embodiment, unlike the above-described seventh embodiment, the path search window width when narrowing is changed and set based on the maximum delay amount at that time. As a result, the path search window width can be reduced to the minimum within a range where the reception quality is not reduced, and the power consumption can be efficiently reduced.

The present invention is not limited to the above embodiments. For example, in the first to fourth embodiments, the path search window width is changed and set. However, the path search window may be fixed and the path search cycle may be changed and set. The width and the path search cycle may be changed and set at the same time.

In the first to fourth embodiments, the path search window width is changed and set in two steps based on a single threshold. However, two or more thresholds are set. In addition, the path search window width may be changed and set in three or more steps.

In the first to fourth embodiments, the path search window width is set based on each of the maximum delay amount, delay spread, spreading gain, and moving speed. May be comprehensively determined to set the path search window width and the path search cycle.

In the fifth embodiment, the surrounding environment is divided into four areas: “mountain area”, “open area”, “suburb” and “city area”.
Although the classification is made according to the type, a part of them may be used or another environmental classification may be included.

In the fifth embodiment, the surrounding environment is determined based on the pattern of the delay profile. However, instead of performing the automatic determination, the upper-level control unit 9 based on the position information sent from the base station. The determination result may be received, or key input information from the user may be received via the upper control unit 9.

In addition, various modifications can be made without departing from the spirit of the present invention.

[0130]

According to the present invention, the width of the path search window and the interval between the timings of performing the path search are changed according to the communication conditions. Therefore, the path search window width can be reduced or the path search can be performed under good conditions. By extending the timing interval, the frequency of execution of the path search can be reduced, and as a result, the wireless reception that can reduce the power consumption related to the path search without deteriorating the reception quality can be achieved. Device.

According to another aspect of the present invention, the reliability of a path table is determined as a ratio of a path whose correlation output level is equal to or lower than a predetermined threshold value among n paths indicated in the path table. If the reliability of the path search is equal to or more than a certain value, the path maintenance is performed, so that the path maintenance can be performed as much as possible to reduce the frequency of performing the path search. The wireless receiving device is capable of reducing the power consumption for the search.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main configuration of a wireless receiving apparatus according to each embodiment of the present invention.

FIG. 2 is a flowchart showing an operation procedure of the correlator 4 in FIG. 1 in the first embodiment of the present invention.

FIG. 3 is a flowchart showing an operation procedure of a path search control unit 8 in FIG. 1 according to the first embodiment of the present invention;

FIG. 4 is a flowchart showing an operation procedure of a path search control unit 8 in FIG. 1 in a second embodiment of the present invention;

FIG. 5 is a flowchart showing an operation procedure of a path search control unit 8 in FIG. 1 in a third embodiment of the present invention.

6 is a flowchart showing an operation procedure of a path search control unit 8 in FIG. 1 in a fourth embodiment of the present invention.

FIG. 7 is a flowchart showing an operation procedure of a correlator 4 in FIG. 1 in a fifth embodiment of the present invention.

8 is a flowchart showing an operation procedure of a path search control unit 8 in FIG. 1 in a fifth embodiment of the present invention.

FIG. 9 is a diagram showing an example of a delay profile pattern in a mountain area.

FIG. 10 is a diagram showing an example of a delay profile pattern in an open land.

FIG. 11 is a diagram showing an example of a delay profile pattern in a suburb.

FIG. 12 is a diagram showing an example of a delay profile pattern in an urban area.

FIG. 13 is a flowchart showing an operation procedure of a correlator 4 in FIG. 1 in a sixth embodiment of the present invention;

FIG. 14 is a flowchart showing an operation procedure of a path search control unit 8 in FIG. 1 in a sixth embodiment of the present invention.

FIG. 15 is a diagram showing an example of how a threshold α is changed according to a peak level / interference / noise level in a sixth embodiment of the present invention.

FIG. 16 is a diagram schematically showing a change in assignment of a path search window width by a path search control unit 8 according to the seventh embodiment of the present invention.

FIG. 17 is a flowchart showing an operation procedure of the path search control unit 8 in FIG. 1 in the eighth embodiment of the present invention;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Antenna 2 ... High frequency circuit (RF circuit) 3 ... A / D conversion part 4 ... Correlator 5 ... Signal power integrator 6 ... Path search part 7 ... Path table 8 ... Path search control part 9 ... Host control part

Claims (6)

[Claims] 1. A radio receiving apparatus for performing direct spread spectrum spread communication, wherein a path search for a phase within a predetermined path search window width centered on a phase of a captured main path is performed at predetermined timings. A path search means for changing at least one of the path search window width and the timing interval for performing the path search, and a maximum delay path which is most delayed from a peak level path detected by a past path search. Path search control means for changing and setting at least one of the path search window width and the timing interval used by the path search means based on the amount of delay from the peak level path. Wireless receiver. 2. A radio receiving apparatus for performing direct spread spectrum spread communication, wherein a path search for a phase within a predetermined path search window width centered on a phase of a captured main path is performed at predetermined timings. A path search means for changing at least one of the path search window width and a timing interval for performing the path search; and a path search means based on a delay spread obtained from a past path search result. And a path search control means for changing and setting at least one of the path search window width and the timing interval. 3. A radio receiving apparatus for performing direct spread spectrum spread communication, wherein a path search for a phase within a predetermined path search window width centered on a phase of a captured main path is performed at predetermined timings. And a path search means capable of changing at least one of the path search window width and the timing interval for performing the path search, and the path search window width and the path search window width used by the path search means based on spreading gain. A wireless communication apparatus comprising: a path search control unit configured to change and set at least one of the timing intervals. 4. A radio receiving apparatus for performing direct spread spectrum spread communication, wherein a path search for a phase within a predetermined path search window width centered on a phase of a captured main path is performed at predetermined timings. A path search unit that can change at least one of the path search window width and the timing interval; and performs the path search window width and the path search used by the path search unit based on a moving speed. A radio receiving apparatus comprising: a path search control unit that changes and sets at least one of timing intervals. 5. A radio receiving apparatus for performing direct spread spectrum spread communication, wherein a path search for a phase within a predetermined path search window width centered on a phase of a captured main path is performed at predetermined timings. A path search means for changing at least one of the path search window width and the timing interval; a peripheral environment recognizing means for recognizing a peripheral environment for generating a multipath; And a path search control means for changing and setting at least one of the path search window width used by the path search means and an interval of timing for performing the path search based on the set surrounding environment. Wireless receiver. 6. A radio receiving apparatus for performing direct spread spectrum spread communication, comprising: a path search means for performing a path search for a phase within a predetermined path search window width centered on a phase of a captured main path. Path maintenance means for performing path maintenance for searching only for n paths whose transmission path response values are indicated in the path table; and determining whether a correlation output level is predetermined among the n paths indicated in the path table. Path search control for causing the path maintenance to be repeatedly performed without performing the path search until the ratio of paths that are equal to or less than the threshold value becomes equal to or less than a predetermined reference ratio, and performing a path search when the ratio becomes equal to or less than the reference ratio. Wireless receiving apparatus comprising: