JP5321659B2 - Preamble receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve reception property of a preamble. <P>SOLUTION: A preamble receiver comprises: a receiving part for receiving signals sent by a transmitter in a preamble interval and a CP interval continuous with the preamble interval, in the preamble interval, the CP interval and a margin interval subsequent to these intervals; a correlation processing part for performing correlation processing every time a search window is moved in which correlation is calculated between part of the reception signal entering the search window moving in the delay direction on a time line by a unit of the CP interval length with a starting point of the preamble interval as a movement start position and a replica signal of the signal transmitted in the preamble interval, and for creating a electric power profile in relation to the result of the correlation processing; and a creation part for creating a composite electric power profile by synthesizing each of the electric power profiles created. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to a preamble receiver, and for example, to an apparatus that receives a preamble transmitted from a transmitter such as a mobile terminal using a random access channel (RACH).

At the International Standardization Meeting (3GPP), LTE (Long Term Evolution) is a next-generation mobile communication specification that is currently being developed. In the LTE specification, when a mobile terminal (terminal) wants to transmit information to a base station using an uplink, the terminal performs an operation for synchronization using a random access channel (RACH).

In the LTE specification, communication is performed with 0.5 [ms] as a basic unit (subframe). Therefore, when communication is performed, each terminal adjusts the timing in accordance with an interval of 0.5 [ms]. Thereafter, communication is performed. Specifically, the terminal performs an operation to synchronize with the base station at the moment when the terminal is turned on or when it returns from outside the service area. Such a synchronization method is roughly divided into the following two steps.
[1] Terminal reception timing synchronization using broadcast information such as SCH (Synchronization Channel) and BCH (Broadcast Channel) [2] Terminal transmission timing synchronization using RACH Regarding the reception timing synchronization of [1] above, Each of the plurality of terminals located in the cell has a predetermined subframe interval (0.5 [ms]) determined by the base station based on information recorded in the SCH and BCH broadcasted by the base station to the entire cell. ) Know the timing. However, the distance between each terminal and the base station is different for each terminal. For this reason, when viewed in absolute time, a delay corresponding to the distance of each terminal occurs at the timing determined by the base station (see FIG. 1). However, when the base station performs only transmission to the terminal using the downlink, even if a delay occurs, it is only necessary to know the terminal as long as the subframe interval, and such a level of synchronization is sufficient.

  Next, the transmission timing synchronization of [2] will be described. When the terminal wants to transmit information to the base station in the uplink, a restriction on synchronization is added. A RACH operation performed before the terminal performs uplink transmission will be described.

  The current LTE specification requires that the timing at which the transmission signal from each terminal arrives at the base station matches at the base station. For this reason, a terminal far from the base station needs to transmit early considering a delay according to the distance, and a terminal close to the base station needs to transmit late. RACH is used to measure the delay time during transmission for each terminal. Specifically, each terminal sends a RACH signal to the base station, and the base station uses the RACH signal to determine the delay amount of each terminal and returns it to each terminal (see FIG. 2).

Each terminal adjusts the transmission timing in consideration of the delay amount according to the location of each terminal. As a result, the base station can receive transmission signals from all terminals at the same timing (see FIG. 3). The amount of delay of each terminal at this time is influenced by the signal round trip time. This round trip time is called RTT (Round Trip Time).

  Next, the operation of processing the RACH signal transmitted from the terminal at the base station will be described. The RACH signal is transmitted in a format different from that of normal data communication. FIG. 4 is an explanatory diagram of a general format of the RACH subframe.

As a unit of subframe, 0.5 ms is set as one unit (TTI). The subframe has a format including sections of “T _DS ”, “Preamble (preamble)”, “T _GP ”, and “T _DS ”. The preamble section is a section in which a RACH signal (preamble) for calculating a delay time is transmitted. The section T _DS preceding the preamble section is RACH.
This is a margin (guard time) for preventing the other signal and the RACH signal from overlapping when another signal before the signal is delayed (see FIG. 5). Interval T _GP subsequent to the preamble section is margin section for compensating the delay caused by the difference in distance of each terminal.

Since no delay occurs in the terminal directly under the base station, the RACH signal reaching the base station has the same form as in FIG. On the other hand, the terminal located at the cell edge for maximum delay occurs, RACH signal from the terminal to reach the base station in a state of delayed until the end of the T _GP. FIG. 6 shows a received RACH signal from a terminal farthest from the base station. The value of the interval T _GP (length) is determined by the maximum cell radius envisaged.

In addition, the interval T _DS is provided after the interval T _GP. This section T _DS is a margin provided to cope with the multipath delay of the RACH signal itself (see FIG. 7). That is, the section T _DS functions as a guard time for properly receiving the RACH signal even when a multipath delay occurs in the RACH signal from the terminal farthest from the base station.

  As described above, the RACH signal transmitted from the terminal has a delay time corresponding to the distance between the terminal and the base station and the multipath when received by the base station.

The base station obtains the delay time of each RACH signal using a RACH signal (preamble signal: hereinafter also referred to as “preamble”) received from each terminal. Specifically, the base station
The delay time is obtained by correlating the received RACH signal and its replica signal.

The RACH reception process is the following process. When the image of the RACH signal (preamble: RACH Preamble) shown so far is drawn correctly, the RACH signal has a waveform of a certain function as shown in FIG. The waveform of the RACH signal is generally created using a special function called CAZAC. The CAZAC waveform (CAZAC sequence) has a characteristic that continuity is maintained before and after the waveform, as shown in FIG. In the RACH correlation process in the RACH reception process, a process using this characteristic is executed.

In the RACH correlation process, the correlation between the received RACH signal and the RACH pattern (replica signal) known by the base station is calculated. FIG. 10 is an explanatory diagram of the RACH correlation process. Receive R
The correlation between the ACH signal and the replica signal is calculated, and a waveform after correlation processing (referred to as “power profile”) is created. In the power profile, a peak is detected from a predetermined time interval (referred to as a “search interval”). The starting point of the search section depends on the preamble,
It is the earliest timing when the peak appears. The length of the search interval corresponds to the maximum delay time, and when the cell radius is maximum, it corresponds to a margin interval (T _GP + T _{DS in} this example) following the preamble interval. The distance between the start position (starting point) of the search section and the peak position is obtained as the delay time.

Therefore, when there is no delay in the received RACH signal (for example, when the terminal is located immediately below the base station), a peak appears at the beginning (starting point) of the search section in the power profile after the correlation processing. On the other hand, the power profile obtained from the signal delayed to the maximum at the cell edge or the like has a peak near the end position (end point) of the search section.

  Basically, as shown in FIG. 11, a preamble section (FIG. 11A) and a replica signal section (FIG. 11B) corresponding to the preamble section are used as sections compared for obtaining correlation. In FIGS. 11A and 11B, intervals are shown on the time axis, but there is also a method of obtaining a correlation after performing discrete Fourier transform (DFT) on such intervals to the frequency domain.

  Note that, when the correlation is taken in the time domain, convolution integration processing is performed, and the processing amount increases. On the other hand, when the time domain is converted to the frequency domain, the convolution integration process in the time domain can be replaced with the multiplication process, so that the processing amount is reduced. Since the processing amount of “DFT + multiplication + IDFT (inverse discrete Fourier transform)” is smaller than the processing amount for performing convolution in the time domain, processing in the frequency domain is often used.

  The correlation processing shown in FIGS. 10 and 11 assumes a received RACH signal with no delay. A problem occurs when the received RACH signal has a delay. FIG. 12 is an explanatory diagram of processing when a delay occurs. As shown in FIG. 12A, the RACH signal received at the base station usually has a delay corresponding to the distance from the terminal. For this reason, the waveform of the RACH signal is shifted to the rear side of the preamble section. When the preamble section is cut out in this state, the cut out signal is in a state where the first half portion is missing. Such a cut-out signal cannot be used in the correlation process as it is.

In order to solve such a problem without changing the cut-out section from the received RACH signal, processing as shown in FIG. 12B is performed. Specifically, a process of adding a signal that protrudes in a margin section (T _GP + T _DS ) provided as a countermeasure against delay from the front side to a preamble section used in correlation processing (hereinafter referred to as “Overlap-and-add (OAA)”). ”).

Conventionally, in OAA, received contents in a margin section (T _GP + T _DS in this example) are cut out. The received content of the cut section is superimposed on the preamble section in a state where the starting point coincides with the starting point (target reception timing) of the preamble section. Then, the RACH signal is C
Since it has an AZAC waveform, the tail end of the added portion of the RACH signal by the OAA in the search interval and the beginning of the RACH signal received in the preamble interval are continuously connected. Such preprocessing is executed before the correlation processing. This makes it possible to extract (cut out) one unit of continuous RACH signals from the cut out section (preamble section).

In this way, by performing OAA before the correlation processing, it is possible to correlate the delayed RACH signal. FIG. 13 is an explanatory diagram of the correlation processing related to the delayed signal for which preprocessing has been completed. A preamble section is cut out from the delayed RACH signal for which preprocessing has been completed, and compared with a replica signal corresponding to this, a power profile is obtained. In the power profile, a portion where the extracted signal waveform matches the replica signal waveform appears as a peak. The difference between this peak position (preamble reception timing) and the start point of the search section (target reception timing) is calculated as a delay time (see FIG. 14). The base station informs the terminal of the delay time value (delay amount). Thereby, the terminal can know the delay time and can determine the transmission timing to the base station.

  Here, the RACH signal transmitted by the terminal and the replica signal known by the base station will be described. A CAZAC sequence is generally used as a sequence for generating a RACH signal. Several CAZAC sequences are selected and used to create a RACH signal. At this time, in order to separate the CAZAC patterns, the CAZAC patterns need to be orthogonal to each other. As the sequence length of the CAZAC sequence becomes longer, the orthogonal pattern for the pattern increases (see FIG. 15).

FIG. 16 shows an example using 16 CAZAC patterns as an example. The terminal basically selects one of a plurality of CAZAC patterns at random and transmits it as a RACH signal (preamble). In FIG. 16, pattern 6 is selected and transmitted.

The base station knows 16 patterns of CAZAC sequences used in RACH (BCH
In some cases, the terminal is notified through a broadcast channel such as The 16 patterns of replica signals are used for correlation processing.

  17 and 18 are explanatory diagrams of correlation processing by the base station. The base station does not know the CAZAC pattern included in the received RACH signal. For this reason, the base station performs correlation processing for all CAZAC patterns (16 patterns in this example). When correlation processing is performed between matching patterns, a peak occurs in the power profile. On the other hand, no peak occurs between unmatched patterns. Therefore, in the example shown in FIGS. 17 and 18, the delay time can be calculated from the power profile obtained through the correlation process using the replica signal of the pattern 6.

“E-UTRA Random Access Preamble Design”, Athens, Greece, March 27-31, 2006, TSG-RAN WG1 # 44bis, R1-060998

  The actual waveform of the RACH signal received at the base station includes noise. FIG. 19A is a diagram illustrating an example of a RACH signal including noise, and FIG. 19B is a diagram illustrating a case where OAA is performed on a RACH signal including noise. However, in FIGS. 19A and 19B, for the sake of explanation, the portion other than the signal transmitted in the preamble section at the terminal is depicted as not including noise, but noise is also mixed in the RACH signal (preamble).

In the conventional OAA, it performed (in FIG. 19B, all the contents received T _GP and T _DS) all received content in the margin section subsequent to the preamble section the superimposition and addition processing in the preamble section only once. At this time, noise included in the margin section is also added to the preamble section. Accordingly, there is a problem that noise is mixed with the RACH signal (preamble) received in the preamble section, and the characteristics of the preamble deteriorate.

  In addition to the case where such OAA processing is performed, it is preferable to improve the reception characteristics of the preamble in order to properly synchronize the communication reception side and the transmission side.

  An object of the present invention is to provide a technique capable of improving the reception characteristics of a preamble.

  The present invention employs the following means in order to achieve the object described above.

That is, according to a first aspect of the present invention, a receiving unit that receives a frame having a format including a preamble section and a margin section following the preamble section from a transmission device;
A reception processing unit for detecting a preamble signal transmitted in the preamble section in the transmission device from a frame received by the reception unit;
The reception processing unit has a predetermined starting point, defines a time equal to or shorter than the margin interval as a search interval, and performs correlation processing on a plurality of division intervals obtained by dividing the search interval. A correlation processing unit for creating a power profile for each divided section;
A preamble receiving apparatus including a generating unit that generates a connected power profile obtained by connecting the power profiles of the divided sections.

  Preferably, the correlation processing unit according to the first aspect of the present invention extracts a predetermined section of the time domain used for the correlation process from the frame, converts the predetermined section into a frequency domain, and performs the correlation process. The power profile is obtained by converting again to the time domain.

  Preferably, the reception processing unit according to the first aspect performs the correlation process after performing the overlap-and-add process of the divided sections with respect to the section used for the correlation process in the frame.

Preferably, in the first aspect of the present invention, a CP portion by a cyclic prefix or a cyclic postfix is added to the preamble signal,
The CP portion has a length shorter than the margin interval;
The search section is divided into a plurality of divided sections in consideration of the CP partial length, and the correlation processing unit is configured to perform the correlation processing for each divided section.

Preferably, in the first aspect of the present invention, the preamble signal is configured by repeating a single pattern, or a CP portion by a cyclic prefix or a cyclic postfix longer than a search interval is added. The correlation processing unit performs correlation processing on the first and second sections in the frame for each divided section to create first and second power profiles, and generates a combined power profile obtained by synthesizing the first and second power profiles. make,
The first section is a section starting from a position delayed by the length of the divided section from the earliest reception timing of the preamble signal in the frame, and starting from a position delayed by a single pattern length therefrom.
The second section is a section having a starting point delayed from the starting point of the first section and having the same length as the first section length that overlaps the first section by the divided section length;
The creation unit is configured to create a connected power profile obtained by connecting combined power profiles for each divided section.

  In this case, the correlation processing unit may create a combined power profile in which power is added to the first power profile and the second power profile. Alternatively, the correlation processing unit may create a combined power profile in which the first power profile and the second power profile are added in phase.

According to a second aspect of the present invention, a receiving unit that receives a frame having a format including a preamble section and a margin section that follows the preamble section from the transmission device;
A preamble signal transmitted in the preamble section in the transmitter from the frame received by the receiver, a signal consisting of a single pattern repetition, or a cyclic prefix or cyclic longer than the search section A reception processing unit that detects a signal to which a CP part by postfix is added,
The reception processing unit creates a power profile for these first and second sections through correlation processing for the first and second sections in the frame;
A combining unit that generates a combined power profile by combining the power profiles related to the first and second sections;
The first section is a section starting from a position delayed by the search section length from the earliest reception timing of the preamble signal in the frame, and starting from a position delayed by a single pattern length therefrom. The second section has a starting point delayed from the starting point of the first section, and overlaps the first section with the search section length (maximum delay time length). This is a preamble receiver that is a section of the same length.

According to a third aspect of the present invention, there is provided a receiving unit that receives a frame having a format including a preamble section and a margin section that follows the preamble section from the transmitting apparatus, and the transmission apparatus that receives the frame received by the receiving unit. In a preamble receiving apparatus including a reception processing unit that detects a preamble signal transmitted in the preamble section at
The reception processing unit
Each of the divided sections has a predetermined starting point, and a time equal to or shorter than the margin section is defined as a search section, and through correlation processing of preamble signals for a plurality of divided sections obtained by dividing the search section. Create a power profile for
Create a concatenated power profile that concatenates the power profiles for each of the divided sections,
A preamble reception processing method including detecting a preamble signal from the connected power profile.

According to a fourth aspect of the present invention, there is provided a receiving unit that receives a frame having a format including a preamble section and a margin section that follows the preamble section from the transmitting apparatus, and the transmitting apparatus from the frame received by the receiving section. Detects a preamble signal transmitted in the preamble section, which is a signal consisting of a single pattern repetition, or a signal with a cyclic prefix or cyclic postfix added to the search section longer than the search section. In a preamble receiving device including a receiving processing unit,
The reception processing unit
Creating a power profile for the first and second intervals through correlation processing for the first and second intervals in the received frame;
Creating a power profile that combines the power profiles for the first and second intervals;
Detecting a preamble signal from the combined power profile;
The first section is a section starting from a position delayed by the search section length from the earliest reception timing of the preamble signal in the frame, and starting from a position delayed by a single pattern length therefrom.
The second section is a section having a starting point delayed from the starting point of the first section and having the same length as the first section length that overlaps the first section by the search section length. This is a preamble reception processing method.

  According to the present invention, it is possible to improve the reception characteristics of the preamble in the receiving apparatus. As a result, it is possible to perform proper preamble detection, delay amount calculation, and consequently transmission timing control.

It is explanatory drawing of a reception timing synchronization of a terminal. It is explanatory drawing of the transmission timing synchronization using RACH of a terminal. It is explanatory drawing of the transmission timing synchronization using RACH of a terminal. It is format explanatory drawing of a RACH signal (RACH sub-frame). It is an explanatory view of T _DS on the RACH subframe. It is explanatory drawing of the reception RACH signal delayed to the maximum. It is a figure which shows the mode of a multipath delay. It is explanatory drawing of the preamble waveform of a RACH signal. It is explanatory drawing of the characteristic of a preamble (CAZAC waveform). It is explanatory drawing of the correlation process of a RACH signal without a delay. It is explanatory drawing of the area which takes the correlation in a reception RACH signal. It is explanatory drawing of the area which takes the correlation of a replica signal. It is explanatory drawing of the RACH signal which has a delay. It is explanatory drawing of the Overlap-and-add system as a pre-process of a correlation process. It is explanatory drawing of the correlation process with respect to a delay signal. It is explanatory drawing of delay amount. It is explanatory drawing of a CAZAC pattern. It is a figure explaining the example of a CAZAC pattern (preamble pattern) and the preamble transmission process by a terminal. It is explanatory drawing of the correlation process in a base station. It is explanatory drawing of delay time calculation through the correlation process which concerns on a some pattern. It is a figure which shows the state before Overlap-and-add of the RACH sub-frame containing noise. FIG. 19B is a diagram showing a state after overlap-and-add of the RACH subframe shown in FIG. 19A. It is a figure which shows the waveform at the time of the terminal transmission of the RACH signal used with the 1st preamble reception system which concerns on 1st Embodiment of this invention. It is a figure which shows the state at the time of reception in the base station of the RACH signal shown to FIG. 20A. It is explanatory drawing which shows the example of the 1st preamble reception system (division overlap-and-add system). It is explanatory drawing of the advantage of a division | segmentation Overlap-and-add system. It is a figure explaining the comparison of the power profile of a prior art example and this invention (divided overlap-and-add system). It is a figure which shows the structural example of the base station (preamble receiver) which can apply a division | segmentation OAA system. It is explanatory drawing of the RACH channel and other channel in a reception baseband signal (frame). It is a figure which shows the structural example of the correlation process part in 1st Embodiment. It is a figure which shows the other structural example of the base station which can apply a division | segmentation OAA system. It is explanatory drawing of the normal RACH signal waveform which does not use CP. It is explanatory drawing of the RACH signal waveform to which CP (cyclic prefix) was added. It is explanatory drawing of the RACH signal waveform to which CP (cyclic postfix) was added. It is explanatory drawing of the 2nd preamble reception system (receiving process of preamble with CP) which concerns on 2nd Embodiment of this invention. It is explanatory drawing of the synthetic | combination power profile finally obtained by the 2nd preamble reception system. It is a figure which shows the structural example of the correlation process part applicable to a 2nd preamble reception system. It is a figure which shows the waveform (transmission waveform) at the time of the terminal transmission of the flame | frame containing the preamble which has a repetition of a single series (single pattern). It is a figure which shows the waveform (reception waveform) at the time of the terminal reception of the flame | frame shown to FIG. 33A. It is explanatory drawing of the 3rd preamble reception system (reception process of the preamble which has a repetition pattern). It is explanatory drawing of the power profile obtained by the correlation process of the 1st time in the reception process shown in FIG. FIG. 35 is an explanatory diagram of a power profile obtained by a second correlation process in the reception process shown in FIG. 34. It is explanatory drawing of the synthetic | combination power profile obtained by synthesize | combining the electric power profile obtained by each correlation process by electric power addition or in-phase addition. It is a figure which shows a process example when it is a 3rd preamble reception system and does not divide | segment a search window (search area). It is a 3rd preamble reception system, Comprising: It is a figure which shows the process example at the time of dividing a search window (search area) into two. It is a figure which shows a process example when it is a 3rd preamble reception system and a search window (search area) is divided into three. It is a figure which shows the structural example of the correlation process part applicable to a 3rd preamble reception system.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The configuration of the embodiment is an exemplification, and the present invention is not limited to the configuration of the embodiment.

[First Embodiment]
As a first embodiment, when a RACH signal having a single CAZAC waveform (single pattern) is received from a terminal to a base station with a delay time, a divided overlap that obtains a power profile in which the influence of noise is suppressed is obtained. The -and-add method (first preamble reception method) will be described.

In the first embodiment, a search section (search window) for performing overlap-and-add (OAA) is divided into a plurality of divided sections (divided windows), and OAA and correlation processing (power profile creation) are performed for each divided section. ) To create a connected power profile obtained by connecting the power profiles related to the respective divided sections, and calculate a delay time based on the connected power profile.

  FIG. 20A shows a RACH subframe (RACH signal transmission waveform) transmitted from the terminal, and FIG. 20B shows a RACH signal reception waveform (subframe) received by the base station. As shown in FIG. 20A, the RACH subframe has a predetermined length N, and has a format in which a margin section M1, a preamble section R, and a margin section M2 are defined from the starting point.

Margin section M1 corresponds to the interval T _DS in the LTE specification. The preamble section R is a section in which a signal (preamble) used for correlation processing is transmitted, and corresponds to a preamble section in the LTE specification. The margin section M2 corresponds to the section T _GP + T _DS in the LTE specification. In the preamble section R, the terminal transmits a RACH signal (preamble) for delay time measurement having a CAZAC waveform (CAZAC sequence).

  When the subframe shown in FIG. 20A is received by the base station, the received RACH signal has a delay corresponding to the distance between the terminal and the base station and includes noise as shown in FIG. 20B. .

FIG. 21 is an explanatory diagram showing the processing contents of the divided overlap-and-add scheme according to the present invention. In FIG. 21, a case where the search section is divided into two divided sections (two search sections are defined) will be described in order to simplify the description. Further, a search time having a predetermined starting point that is equal to or shorter than the margin interval M2 is defined as a search interval, and OAA and correlation processing are executed for each divided interval. In the following description, the cell radius is the maximum (margin interval length = maximum delay time length), but the same applies when the maximum delay time length is shorter than the margin interval.

  However, the division | segmentation area number can determine arbitrary numbers two or more. Further, the sizes of the divided sections may be the same size or may be defined by different sizes. Furthermore, the number of divisions (division density) per predetermined time can be arbitrarily set.

As shown in FIG. 21, in the first OAA and correlation processing, the first half (divided section D1) when the margin section M2 is divided into two equal parts is overlap-and-added to the preamble section R. Subsequently, a preamble section R is cut out as a DFT section 1 as a section used for correlation processing. The DFT section 1 is transformed into the frequency domain by DFT (Discrete Fourier Transform) and then correlated with the replica signal. After that, IDFT is performed, the frequency domain is converted again into the time domain, and a power profile is created. As a result, the power profile P1 of the first half when the margin section is divided into two equal parts is obtained.

Next, in the second OAA and correlation processing, the next divided section in the margin section M2 (the second half portion (the divided section D2) in the example of FIG. 21) is the length of the divided section D1 behind the starting point of the preamble section R. Overlap-and-add is started from the position shifted by that amount. Subsequently, a section whose starting point is a position shifted backward from the starting point of the preamble section R by the length of the divided section D1 and whose end point is a position advanced backward by the preamble length therefrom is cut out as a DFT section 2. Then, DFT, correlation processing, IDFT, and power profile creation for this DFT section 2 are executed. As a result, the power profile P2 in the latter half of the margin section is created.

  Finally, a process of creating one power profile waveform by connecting the two power profiles P1 and P2 on the same time axis is performed to obtain a connected power profile X. Based on the peak position in the connected power profile X, the delay amount is calculated.

  In the above example, the case where the number of search section divisions (number of search sections) is 2 has been described. However, the number of OAA and the correlation process corresponding to the number of divisions are repeatedly performed in the same manner as described above, Finally, a coupled power profile is created and used for delay calculation.

The divided OAA system as described above is different from the prior art in the following points.
(1) The search section (search window) is divided and a plurality of correlation processes are performed.
(2) The cut-out section (DFT section) for correlation processing is shifted backward by the length of the divided section used in the correlation processing executed earlier. However, the order of the divided sections on which the correlation processing is performed can be arbitrarily determined, and a configuration in which processes related to a plurality of divided sections are executed in parallel can also be adopted.

<Advantages of split OAA method>
The divided overlap-and-add scheme has the following advantages. FIG. 22 is an explanatory diagram of the advantages of the divided overlap-and-add scheme, and represents the first correlation process (calculation for the first half of the search interval (division interval D1)) in the example shown in FIG. .

Conventionally, overlap-and-add is performed only once for the entire search section. In contrast,
In this method, overlap-and-add is performed only in the first half of the search interval. As a result, it is possible to obtain a correlation processing waveform (DFT section 1) that does not include noise included in the latter half of the search section. Therefore, the waveform of the power profile after the correlation processing is appropriate as compared with the conventional case.

Also for the second calculation (correlation process), a power profile with less influence of noise can be obtained as in the first correlation process. However, in the example shown in FIG. 21, no peak appears in the latter half (divided section D2), so it is not so meaningful. However, when the delay increases, a peak appears in the latter half (divided section D2). If this happens, the first calculation will be meaningless.

  FIG. 23 shows a comparison between the conventional example and the present invention (first embodiment) in terms of power profiles. The vertical axis represents the amplitude of the power profile, normalized by 0 [dB]. The horizontal axis represents time, and in FIG. 23, a peak is shown in the vicinity of 22 [μs].

The conventional example is represented by a dotted line, and the present invention (first embodiment) is represented by a solid line. As a power profile according to the present invention, a result obtained by dividing an overlap-and-add section (search section) into four parts is shown. As shown in FIG. 23, it can be seen that the noise level is reduced by the present invention. Therefore, the reception characteristics of the RACH signal are improved by applying the present invention.

<Configuration of base station (receiver)>
FIG. 24 is a diagram illustrating a configuration example of a preamble receiving apparatus according to the present invention, and illustrates a configuration example of a base station capable of executing the divided OAA scheme according to the present invention. 24, a base station apparatus 10 as a preamble receiving apparatus includes a transmission / reception antenna 11, a radio section 12 as a receiving section, a channel separation section 13, a RACH reception processing section 14 as a reception processing section, and transmission timing control. Unit 17 and a transmission signal baseband processing unit 18. The RACH reception processing unit 14 includes a correlation processing unit 15 and a preamble & path timing detection unit 16.

  The radio unit 12 performs radio signal transmission / reception processing (including baseband signal modulation / demodulation processing). For example, the radio unit 12 receives a radio signal from a terminal received by the transmission / reception antenna 11, performs amplification and demodulation processing, and outputs a demodulated signal (baseband signal) to the channel separation unit 13.

The channel separation unit 13 receives a frame as illustrated in FIG. 25 from the wireless unit 12 as a baseband signal. The frame is in a state where a plurality of channels are multiplexed in time and frequency, and the channel separation unit 13 performs the RACH subframe (RACH subframe) from the frame.
(Receiving baseband signal: frame in the present invention)
Send to 4.

  At this time, the RACH reception baseband signal (RACH subframe) has a format as shown in FIG. 20B and includes a preamble (RACH signal) delay and noise.

The correlation processing unit 15 uses the divided OAA scheme described above to receive the RACH reception baseband signal (
A connection power profile is created from the (RACH signal) and passed to the preamble and path timing detection unit 16.

  The preamble & path timing detection unit 16 (hereinafter referred to as “detection unit 16”) determines whether or not the preamble is included in the connected power profile. Specifically, the detection unit 16 has a predetermined power threshold, and if there is a part (peak) exceeding the power threshold in the connected power profile, it detects it as a preamble. At this time, the detected preamble pattern is specified. The preamble pattern is identified by a preamble number.

Further, if the preamble is included, the detection unit 16 calculates the difference between the reception timing of the preamble (detected preamble (peak) timing t ₀ ) and the target timing (start point of the search section), and the delay amount Is calculated. The detection unit 16 sends the preamble number and the delay amount to the transmission timing control unit 17.

  The transmission timing control unit 17 determines a transmission timing for the uplink of the terminal based on the delay amount, and creates a transmission timing control command for the terminal. The transmission timing control unit 17 sends a transmission timing control command and a preamble number (pattern identification number) to the transmission signal baseband processing unit 18.

  The transmission signal baseband processing unit 18 creates a transmission baseband signal including a transmission timing control command and sends it to the radio unit 12. The radio unit 12 modulates and amplifies the transmission baseband signal and transmits it from the transmission / reception antenna 11.

  The processing described above is executed for each terminal located in the cell of the base station apparatus 10, and the uplink transmission timing in each terminal is adjusted. Thereby, the base station apparatus 10 can receive the information (signal) from each terminal at the same timing.

  FIG. 26 is a diagram illustrating a detailed configuration of the correlation processing unit 15 illustrated in FIG. 24, and illustrates a configuration example for realizing correlation processing (power profile creation) using the divided OAA scheme in the first embodiment. ing.

In FIG. 26, the correlation processing unit 15 divides a search section into a plurality of power profile creation sections 151 prepared for a plurality of divided sections (1, 2,..., M−1, M). A frequency domain preamble replica creation unit 155 (hereinafter referred to as “replica creation unit 155”), and a plurality of search interval connection units prepared for each preamble pattern (1, 2,..., N−1, N) 158 (corresponding to the connecting portion of the present invention). Each power profile creation unit 151 includes an overlap-and-add (overlap and addition: OAA) processing unit 152, a DFT unit 153, and a preamble pattern (1, 2,..., N−1, N). And a plurality of prepared correlation calculators 154.

Each power profile creation unit 151 performs the following processing. Each power profile creation unit 151 receives a RACH subframe (received RACH signal) as shown in FIG. 20B. The OAA processing unit 152 performs OAA for a predetermined division section (search section) on the received RACH signal, and sends it to the DFT unit 153. The DFT unit 153 has a predetermined D
The FT section is cut out, converted to the frequency domain by performing DFT, and sent to the correlation calculation unit 154.

The correlation calculation unit 154 includes a multiplier 156 and an IDFT unit 157. The multiplier 156 calculates the correlation between the DFT section converted into the frequency domain and the replica signal (one of N preamble patterns) received from the replica creation unit 155 to perform a multiplication process. The correlation calculation result is IDFTed by the IDFT unit 157 and output as a time domain power profile. As a result, a correlation processing result (power profile) for the divided section is created and sent to the corresponding search section linking unit 158.

  Each search section coupling unit 158 is configured to receive a power profile for the same preamble pattern (replica signal) from each power profile creation unit 151. Upon receiving the power profiles related to the search sections (divided sections) 1 to M, the search section connecting unit 158 performs a process of connecting them on the same time axis, and creates a connected power profile. The connection power profile for each preamble pattern generated by each search section connection unit 158 is sent to the detection unit 16.

The detection unit 16 extracts a connection power profile having a peak from a plurality of connection power profiles received from the correlation processing unit 15 by a technique as shown in FIG. 18, and specifies a preamble number indicating the pattern.

  In the configuration of the correlation processing unit 15 as described above, it is necessary to create a power profile for all preamble patterns used in the cell. However, it is possible to adaptively change the length of the section (search section) where the frequency domain correlation processing is performed and the number of divisions of the search section according to the use of the preamble pattern.

  For example, when a preamble pattern dedicated to handover and a preamble pattern used for other purposes are separated, the terminal that performs handover is generally located at the cell edge, so the reception timing at the base station is the part after the search interval. become. In this case, with respect to the preamble pattern for handover, for example, by increasing the number of divisions (division density) in the latter half of the search interval, the influence of noise on the concatenated power profile can be suppressed and its characteristics can be improved. In other words, it is possible to improve the reception characteristics of the preamble of the base station.

  FIG. 27 is a diagram illustrating another configuration example of the preamble reception apparatus according to the present invention, and illustrates another configuration example of the base station to which the divided OAA scheme is applicable. In FIG. 27, base station apparatus 10A as a preamble receiving apparatus differs from base station apparatus 10 shown in FIG. 24 in the following points. That is, the RACH reception processing unit 14 includes a preamble detection unit 19 instead of the detection unit 16. Further, the transmission timing control unit 17 is omitted.

  The preamble detection unit 19 has only a function of detecting a preamble among the functions of the detection unit 16, and does not have a configuration for calculating a delay amount. Also, the transmission timing control unit 18 is not provided, and a transmission timing control command corresponding to the delay amount is not notified to the terminal.

  Except for the above points, the base station apparatus 10 </ b> A has the same configuration and functions as the base station apparatus 10. The base station apparatus 10 has a transmission timing control function as a component when conforming to the LTE specification. However, there is also a base station that performs RACH processing that only performs processing for detecting a preamble transmitted from a terminal and does not detect preamble reception timing (does not calculate a delay amount). The base station device 10A shows the configuration of such a base station. Even in this case, a connected power profile in which the influence of noise is suppressed is used as the power profile used for preamble detection, so that it is possible to perform proper preamble detection and thus transmission timing control. In other words, the reception characteristics of the preamble can be improved.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. Since the second embodiment has the same configuration as that of the first embodiment, differences will be mainly described, and description of common points will be omitted.

<CP format>
As a second embodiment, a reception method when the RACH signal has a format using CP will be described. CP is an abbreviation for “Cyclic Prefix” or “Cyclic Postfix”. FIG. 28 is a diagram illustrating an example of a normal RACH signal waveform that does not use a CP, FIG. 29A is a diagram illustrating an example of a RACH signal waveform in which a cyclic prefix is performed, and FIG. 29B is a diagram in which cyclic postfix is performed. An example of a RACH signal waveform is shown.

“Cyclic Prefix” is a method in which a part of the rear side of the RACH signal waveform is copied and added to the front side. On the other hand, “Cyclic Postfix” is a method in which a part of the front side of the RACH signal waveform is copied and added to the rear side. When CP is added to the RACH signal, it becomes longer than a normal signal waveform that does not use CP, so the margin for delay is reduced. In other words, since the amount of delay allowed is reduced, the cell radius must be designed to be small. However, it is known that reception characteristics are improved.

<Second preamble reception method>
Next, preamble reception processing (second preamble reception method) having a format using CP will be described. Here, a method for performing reception processing in multiple steps without performing overlap-and-add will be described.

  FIG. 30 is an explanatory diagram of the second preamble reception method, and shows a state in which a received signal in a format using CP is processed. In the example shown in FIG. 30, the transmission waveform (FIG. 30A) uses “Cyclic Prefix”, and a CP waveform (CP portion) is added before the signal (preamble) transmitted in the preamble section.

  In addition, a margin section (guard time) is provided behind the preamble section. In this example, the guard time length is three times the CP length. In this case, the preamble reception process (correlation process) is performed in three steps. However, the margin section length is longer than the CP length and is configured in an arbitrary size. The number of correlation processes is obtained by “margin section length / CP length” (the remainder is assumed to be one).

As shown in FIG. 30, the transmission waveform has a delay when it is received by the reception device (reception waveform (FIG. 30B)). The received waveform section used in the first correlation process (FIG. 30C) uses the preamble section of the original transmission format. The correlation process itself is the same as the correlation process described in the first embodiment. That is, the preamble section in the received signal (FIG. 3).
0 (C) DFT interval (1)) is cut out, DFT is performed, and after correlation with the replica signal is performed, IDFT is performed to obtain the first power profile (2).

In the second correlation processing (FIG. 30D), the preamble section length section starting from the position shifted backward by the CP length from the first processing is used as the DFT section (2) for the correlation processing. The power profile (2) is obtained.

In the third correlation process (FIG. 30 (E)), the section of the preamble section length starting from the position shifted further from the starting point of the DFT section (2) by the CP length is used as the DFT section (3). Use. Thereby, the third power profile (3) is obtained.

Finally, the power profiles (1), (2), and (3) obtained in each correlation process are combined (connected) to obtain a connected power profile (FIG. 31). It is possible to obtain the total delay time of the preamble having CP from the peak in the coupled power profile.

According to the second preamble reception method, the reception characteristics can be improved without performing overlap-and-add (OAA) by performing reception processing (demodulation processing) in a plurality of times. In other words, it is possible to obtain a correlation process (power profile) that avoids the influence due to the addition of noise accompanying execution of OAA. In other words, an appropriate power profile can be obtained as compared with the power profile obtained through the conventional OAA.

<Receiver configuration>
As the preamble reception apparatus to which the second preamble reception method can be applied, the configuration of the base station apparatus shown in FIG. 24 or FIG. 27 can be applied. However, the correlation processing unit 15 having the configuration shown in FIG. 32 is applied. FIG. 32 is a diagram illustrating a configuration example of a correlation processing unit applied to the second preamble reception method, and illustrates a configuration for performing correlation processing of a preamble with CP.

The correlation processing unit 15 shown in FIG. 32 is different from the correlation processing unit 15 (FIG. 26) applied to the first preamble reception method in that the OAA processing unit 152 is omitted from the power profile creation unit 151. The DFT unit 153 cuts out the corresponding DFT section and performs DFT. Except for the above points, the configuration and function of the correlation processing unit are the same as those in the first embodiment.

[Third Embodiment]
Next, a second embodiment of the present invention will be described. Since the second embodiment has the same configuration as that of the first embodiment, differences will be mainly described, and description of common points will be omitted.

  In addition to the conventional format and the format with CP, a format having a preamble in which a single pattern waveform is repeated a plurality of times has already been proposed (FIG. 33A). In the format example shown in FIG. 33A, preamble sections 1 and 2 for transmitting a preamble in which a certain single pattern is repeated twice are provided, and a margin section (guard time) is provided behind the preamble section. Yes. The preamble having such a format is also received with a delay on the receiving side (FIG. 33B).

<Third preamble reception method>
In the third embodiment, a preamble reception method (third preamble reception method) having such a repetitive pattern will be described. FIG. 34 is an explanatory diagram showing an example of the third preamble reception system.

  In the example shown in FIG. 34, a preamble having a repetitive pattern has a format as shown in FIGS. 33A and 33B, and has a preamble in which a single pattern is repeated twice. In the third preamble reception process, the same number of correlation processes as the number of repetitions of a single pattern are performed. In this example, two correlation processes are performed.

In FIG. 34, in the first correlation process, the position advanced by the guard time length backward from the repeat start position (start point of preamble section 2) of the single pattern is set as the end point, and the single pattern length is returned from the end point to the front side. The section starting from the current position (the section starting from the position shifted from the starting point of the preamble section 1 by the guard time length and starting from the position advanced backward by the single pattern length) is cut out as the DFT section 1 And used for correlation processing. As a result of the correlation process, a first power profile is obtained.

  On the other hand, in the second correlation process, a single pattern length section that overlaps the DFT section 1 by the guard time length is extracted as the DFT section 2. In other words, a section of one half of the preamble in the latter half (preamble section 2) is cut out as DFT section 2 and used for correlation processing. As a result, a second power profile is obtained. Next, a combined power profile is created by combining the first and second power profiles. The combined power profile is created through one of the processes of <1> in-phase addition or <2> power addition.

The power addition process will be described. For each of the first and second power profiles, u _j = a + ib (first (first) power profile)
v _j = c + id (second (second) power profile)
(FIGS. 35A and B). Here, j is a sample number. When these two results are combined by the following (Equation 1), a combined power profile obtained by adding power is obtained (FIG. 36).

Profile after power addition = | a | ² + | b | ² + | c | ² + | d | ² (Expression 1)
Since the resultant power profile obtained in this way is obtained without executing OAA, it does not include the influence of noise caused by OAA. Therefore, a more appropriate power profile can be obtained than when the conventional OAA is executed.

Next, the in-phase addition process will be described. The two obtained results (power profile) are similar to the case of power addition.
u _j = a + ib (first (first) power profile)
v _j = c + id (second (second) power profile)
Is defined as When these two results are combined by the following (Equation 2), a combined power profile obtained by in-phase addition is obtained.

Profile after in-phase addition = (a + c) ² + (c + d) ² (Formula 2)
The combined power profile obtained by in-phase addition also has better characteristics than those obtained through OAA, similar to power addition.

  In-phase addition has good characteristics when the phase shift is small (when the moving speed is slow), and power addition has good characteristics when the phase shift is large (when the moving speed is fast). In general, in an environment of 15 km / h or less, it is considered that a power profile with better characteristics can be obtained by performing in-phase addition.

  FIG. 37 is a diagram illustrating an example of reception processing of a preamble having a repetitive pattern without dividing a search window (search section). The process shown in FIG. 37 is almost the same as the process shown in FIG.

In FIG. 37, the two unit sequences (preambles) described in the first row from the top indicate the preambles (preambles 1 and 2) received at the earliest timing of receiving the preamble at the base station (receiving device), The two unit sequences described in the second stage indicate the preambles (preambles 1 and 2) received at the latest timing of receiving the preamble in the base station. Thus, there is a difference in guard time length between the earliest reception timing and the latest reception timing.

  In the base station, taking into account the difference (guard time length) described above, a section of a range that is advanced backward by a single sequence length starting from a position shifted backward by the guard time length from the earliest timing is a DFT section. A single sequence length section that is extracted as 1 and is located behind DFT section 1 and overlaps by the guard time length is extracted as DFT section 2, and correlation processing is performed for each DFT section. Then, a power profile is created for DFT sections 1 and 2, and power addition or in-phase addition is performed to create a combined power profile.

  In the third preamble reception scheme, the search interval (guard time) can be divided into a plurality of intervals, and the processing shown in FIG. 37 can be performed for each of the division intervals. FIG. 38 shows processing when the search section (search window) is divided into two, and FIG. 39 shows processing when the search section (search window) is divided into three.

In FIG. 38, the guard time (search section) is divided into two equal parts, and the respective divided sections are defined as search sections 1 and 2. In this case, the DFT section 1 related to the search section 1 has a position advanced by 1/2 of the guard time length from the start of the preamble section 2 to the end, and then returns to the front by a single pattern (unit sequence) length from there. Section starting from the last position (Section starting from the position deviated by 1/2 of the guard time length backward from the earliest reception timing and starting from the position advanced from there by a single sequence length) It becomes. On the other hand, the DFT section 2 is the same section as the preamble section 2. The combined power profile obtained through such a process is a power profile for the first half of the entire search section.

  On the other hand, the DFT sections 1 and 2 in the search section 2 are sections that are delayed from the DFT sections 1 and 2 in the search section 1 by ½ of the guard time length. Such a combined power profile related to the search section 2 is the power profile of the latter half of the entire search section. These combined power profiles are connected to create a total combined power profile.

In FIG. 39, the guard time (search section) is divided into three equal parts, and the respective divided sections are defined as search sections 1, 2, and 3. In this case, the DFT section 1 related to the search section 1 returns to the front side by a single pattern (unit sequence) length from a position advanced by 1/3 of the guard time length from the start point of the preamble section 2 to the rear side. The starting point is a position (starting from a position delayed by 1/3 of the guard time length from the starting point of the preamble section 1 and starting from a position delayed by a single sequence length). On the other hand, the DFT section 2 is the same section as the preamble section 2. The DFT sections 1 and 2 in the search sections 2 and 3 are sections delayed by 1/3 of the guard time length from the DFT sections 1 and 2 in the previous search section, respectively. In this way, power profiles for the search sections (divided sections) 1, 2, and 3 are created, and these are connected to obtain the entire search section (total) combined power profile.

  As described above, the reception characteristics can be improved by dividing the search section into a plurality of divided sections.

  The above explanation is for the case of repetition of an integral multiple of a single pattern. However, even when the length of the CP is longer than the search interval, the signal with the CP becomes a partial repetition of the single pattern. Become.

<Receiver configuration>
As a preamble reception apparatus to which the third preamble reception method can be applied, the configuration of the base station apparatus shown in FIG. 24 or 27 can be applied. However, the correlation processing unit 15 having the configuration shown in FIG. 40 is applied.

  FIG. 40 is a diagram illustrating a configuration example of a correlation processing unit applied to the third preamble reception system, and illustrates a configuration for performing correlation processing of a preamble having a repetitive pattern. The correlation processing unit 15 shown in FIG. 40 is different from the correlation processing unit 15 (FIG. 26) of the first embodiment in the following points.

That is, the OAA processing unit 152 is omitted from each power profile creation unit 151. Each correlation calculation unit 154 includes a power profile synthesis unit 160. In addition, two systems of DFT units, multipliers, and IDFT units are provided (DFT units 153A and 153B).
, Multipliers 156A and 156B, IDFT units 157A and 157B). One correlation processing system (153A, 156A, 157A) performs correlation processing for DFT section 1, and the other correlation processing system (153B, 156B, 157B) performs correlation processing for DFT section 2. A delay unit 159 is provided so that the input to the power profile combining unit 160 does not compete, and the power profile in the DFT section 2 is input to the power profile combining unit 160 later than the power profile in the DFT section 1. ing. The same replica signal (replica waveform) is input from the replica creation unit 155 to each of the multipliers 156A and 156B.

The power profile combining unit 160 connects the power profile of the DFT section 1 and the power profile of the DFT section 2 according to, for example, a predetermined addition method (one of power addition or in-phase addition), and obtains the obtained connected power profile. Output.

  The configuration shown in FIG. 40 has a configuration that assumes a case where the search section as shown in FIGS. 38 and 39 is divided into a plurality of divided sections. Therefore, the power profile creation unit 151 is provided for each of the search sections (divided sections) 1 to N, and the power profile of each divided section is output as a combined power profile connected by the search section connecting unit 158. ing. The third preamble reception method (FIGS. 34 and 37) that does not divide the search interval can be realized by providing only one power profile creation unit 151 in the configuration shown in FIG.

In the first to third embodiments described above, the time resolution of the profile may be improved by increasing the IDFT size used in the IDFT unit 157. Further, as a process of returning from the frequency domain to the time domain, the circuit scale may be reduced by using IFFT (Inverse Fast Fourier Transform) instead of IDFT.

[Others]
The embodiment described above discloses the following invention. The invention disclosed below can be combined as appropriate.
(Supplementary Note 1) A reception unit that receives a frame having a format including a preamble section and a margin section following the preamble section from the transmission device;
A reception processing unit for detecting a preamble signal transmitted in the preamble section in the transmission device from a frame received by the reception unit;
The reception processing unit has a predetermined starting point, defines a time equal to or shorter than the margin interval as a search interval, and performs correlation processing on a plurality of division intervals obtained by dividing the search interval. A correlation processing unit for creating a power profile for each divided section;
A preamble receiving device including a creation unit that creates a connected power profile obtained by connecting the power profiles for each of the divided sections. (1)
(Additional remark 2) The said correlation process part extracts the predetermined area of the time domain used for the said correlation process from the said frame, converts this predetermined area into a frequency domain, performs a correlation process, Then, it converts into a time domain again. The preamble receiver according to appendix 1, wherein a power profile is obtained. (2)
(Supplementary note 3) The preamble reception device according to supplementary note 1 or 2, wherein the reception processing unit performs the correlation process after performing an overlap-and-add process of a divided section with respect to a section used for the correlation process in the frame. (3)
(Supplementary Note 4) The preamble signal has a CP portion added by cyclic prefix or cyclic postfix,
The CP portion has a shorter length than the search interval;
The preamble receiving apparatus according to supplementary note 1 or 2, wherein the search section is divided into a plurality of divided sections in consideration of the CP partial length, and the correlation processing unit performs the correlation processing for each divided section. (4)
(Supplementary Note 5) The preamble signal is configured by repeating a single pattern, or has a CP portion added by a cyclic prefix or a cyclic postfix, and the CP portion is longer than the search interval. Has a length,
The correlation processing unit performs correlation processing on the first and second sections in the frame for each divided section to create first and second power profiles, and creates a combined power profile by combining these. ,
The first section is a section starting from a position delayed by the length of the divided section from the earliest reception timing of the preamble signal in the frame, and starting from a position delayed by a single pattern length therefrom.
The second section is a section having a starting point delayed from the starting point of the first section and having the same length as the first section length that overlaps the first section by the divided section length;
The preamble reception apparatus according to appendix 1 or 2, wherein the creation unit creates a connected power profile obtained by connecting combined power profiles for each divided section. (5)
(Additional remark 6) The said correlation process part is a preamble receiver of Additional remark 5 which produces the synthetic | combination power profile by which electric power was added to the said 1st power profile and the said 2nd power profile. (6)
(Supplementary note 7) The preamble reception device according to supplementary note 5, wherein the correlation processing unit creates a combined power profile in which the first power profile and the second power profile are added in phase. (7)
(Supplementary note 8) The preamble reception device according to supplementary note 2, wherein inverse discrete Fourier transform is used in the process of converting to the time domain.
(Supplementary note 9) The preamble receiver according to supplementary note 2, wherein inverse fast Fourier transform is used in the process of converting to the time domain.
(Additional remark 10) The receiving part which receives the flame | frame which has a format containing a preamble area and the margin area following this preamble area from a transmitter,
A preamble signal transmitted in the preamble section in the transmitter from the frame received by the receiver, a signal consisting of a single pattern repetition, or a cyclic prefix or cyclic longer than the search section A reception processing unit that detects a signal to which a CP part by postfix is added,
The reception processing unit creates a power profile for these first and second sections through correlation processing for the first and second sections in the frame;
A combining unit that generates a combined power profile by combining the power profiles related to the first and second sections;
The first section is a section starting from a position delayed by the search section length from the earliest reception timing of the preamble signal in the frame, and starting from a position delayed by a single pattern length therefrom.
The second section has a starting point delayed from the starting point of the first section, and overlaps the first section with the search section length (maximum delay time length). A preamble receiver that is a section of the same length. (8)
(Additional remark 11) The said correlation process part converts the 1st and 2nd area of a time domain from the said frame to a frequency domain, performs a correlation process, Then, converts again into a time domain, and the said 1st and 2nd 11. The preamble receiver according to appendix 10, which obtains a power profile related to the interval.
(Additional remark 12) The said correlation process part is a preamble receiver of Additional remark 10 or 11 which produces the synthetic | combination power profile by which electric power was added to the said 1st power profile and the said 2nd power profile.
(Additional remark 13) The said correlation process part is a preamble receiver of Additional remark 10 or 11 which produces the synthetic | combination power profile by which the said 1st power profile and the said 2nd power profile were added in phase.
(Supplementary note 14) The preamble receiver according to any one of supplementary notes 1 to 13, wherein the frame is a random access channel subframe.
(Supplementary Note 15) A receiving unit that receives a frame having a format including a preamble section and a margin section that follows the preamble section from the transmitting device, and a frame received by the receiving unit from the frame received by the transmitting device in the preamble section In a preamble receiving apparatus including a reception processing unit that detects a transmitted preamble signal,
The reception processing unit
Each of the divided sections has a predetermined starting point, and a time equal to or shorter than the margin section is defined as a search section, and through correlation processing of preamble signals for a plurality of divided sections obtained by dividing the search section. Create a power profile for
Create a concatenated power profile that concatenates the power profiles for each of the divided sections,
A preamble reception processing method including detecting a preamble signal from the connected power profile. (9)
(Additional remark 16) The said reception process part extracts the predetermined area of the time domain used for the said correlation process from the said frame, converts this predetermined area into a frequency domain, performs a correlation process, and then converts into a time domain again. The preamble reception processing method according to supplementary note 15, wherein a power profile is obtained.
(Supplementary note 17) The preamble reception processing method according to supplementary note 15 or 16, wherein the reception processing unit performs the correlation process after performing an overlap-and-add process of a divided section with respect to a section used for the correlation process in the frame. .
(Supplementary Note 18) The preamble signal has a CP portion added by cyclic prefix or cyclic postfix,
The CP portion has a shorter length than the search interval;
The preamble reception processing method according to supplementary note 15 or 16, wherein the search section is divided into a plurality of divided sections in consideration of the CP partial length, and the correlation processing is performed for each divided section.
(Supplementary note 19) The preamble signal is configured by repeating a single pattern, or a CP portion having a length longer than the search section by a cyclic prefix or a cyclic postfix is added, The reception processing unit, for each divided section,
First and second power profiles are generated by performing correlation processing on the first and second sections in the frame, and a combined power profile is generated by combining them.
The first section is a section starting from a position delayed by a divided section length from the earliest reception timing of the preamble signal, and having a position delayed by a single pattern length therefrom as an end point.
The second section is a section having a starting point delayed from the starting point of the first section and having the same length as the first section length that overlaps the first section by the divided section length;
The preamble reception processing method according to supplementary note 15 or 16, wherein a combined power profile is created by combining combined power profiles for each divided section.
(Supplementary note 20) The preamble reception processing method according to supplementary note 19, wherein a combined power profile is generated by adding power to the first power profile and the second power profile.
(Supplementary note 21) The preamble reception processing method according to supplementary note 19, wherein a combined power profile is generated by adding the first power profile and the second power profile in phase.
(Supplementary note 22) The preamble reception processing method according to supplementary note 16, wherein inverse discrete Fourier transform is used in the process of converting to the time domain.
(Supplementary note 23) The preamble reception processing method according to supplementary note 16, wherein inverse fast Fourier transform is used in the process of converting to the time domain.
(Supplementary Note 24) A receiving unit that receives a frame having a format including a preamble section and a margin section that follows the preamble section from the transmitting device, and a frame received by the receiving unit from the frame received by the transmitting device in the preamble section A reception processing unit for detecting a transmitted preamble signal, which is a signal consisting of repetition of a single pattern, or a signal to which a CP portion is added with a cyclic prefix or cyclic postfix longer than the search interval; In a preamble receiver including:
The reception processing unit
Creating a power profile for the first and second intervals through correlation processing for the first and second intervals in the received frame;
Creating a power profile that combines the power profiles for the first and second intervals;
Detecting a preamble signal from the combined power profile;
The first section is a section starting from a position delayed by the search section length from the earliest reception timing of the preamble signal in the frame, and starting from a position delayed by a single pattern length therefrom.
The second section is a section having a starting point delayed from the starting point of the first section and having the same length as the first section length that overlaps the first section by the search section length. A preamble reception processing method. (10)
(Supplementary Note 25) The first and second sections in the time domain from the frame are converted to the frequency domain and subjected to correlation processing, and then converted again into the time domain and the power profile relating to the first and second sections. The preamble reception processing method according to appendix 24, wherein:
(Supplementary note 26) The preamble reception processing method according to supplementary note 24 or 25, wherein a combined power profile is generated by adding power to the first power profile and the second power profile.
(Supplementary note 27) The preamble reception processing method according to supplementary note 24 or 25, wherein a combined power profile is generated by adding the first power profile and the second power profile in phase.

10, 10A ... Base station (preamble receiver)
DESCRIPTION OF SYMBOLS 11 ... Transmission / reception antenna 12 ... Radio | wireless part 13 ... Channel separation part 14 ... RACH reception process part 15 ... Correlation process part 16 ... Preamble and path timing detection part 17 ... Transmission timing Control unit 18 ... transmission signal baseband processing unit 151 ... power profile creation unit 152 ... overlap-and-add processing unit 153 ... DFT unit 154 ... correlation calculation unit 155 ... frequency domain Preamble replica creation unit 156... Multiplier 157... IDFT unit 158... Search interval connection unit 159.

Claims (3)

Signals transmitted from a transmitter in a preamble section and a CP section that is a cyclic prefix section or a cyclic postfix section that is continuous with the preamble section, the preamble section, the CP section, and these sections A receiving unit for receiving in a margin section following
The portion of the signal received by the receiving unit that has entered the search window that moves in the delay direction on the time axis in units of CP interval with the start point of the preamble interval as the movement start position, and the signal transmitted in the preamble interval A correlation processing unit that performs correlation processing for calculating correlation with a replica signal for each movement of the search window, and creates a power profile for the result of each correlation processing;
A preamble receiving device including a generating unit that generates a combined power profile obtained by combining the generated power profiles.   The preamble reception apparatus according to claim 1, wherein the number of times of the correlation processing is a value obtained by dividing at least a margin section length by the CP section length. The preamble receiver is
Signals transmitted from a transmitter in a preamble section and a CP section that is a cyclic prefix section or a cyclic postfix section that is continuous with the preamble section, the preamble section, the CP section, and these sections Received in the margin section that follows
The upper time axis CP interval length units starting point as the movement start position of the preamble section enters a search window to move in the retard direction, minute parts of the received signal, the replica signal of the transmitted signal in the preamble interval The correlation process for calculating the correlation with each time the search window is moved, creating a power profile according to the result of each correlation process,
A preamble reception processing method including creating a combined power profile obtained by combining the generated power profiles.

Images