WO2010130170A1

WO2010130170A1 - Method and apparatus for transmitting random access signal, and related method and system

Info

Publication number: WO2010130170A1
Application number: PCT/CN2010/071615
Authority: WO
Inventors: 费佩燕; 秦洪峰
Original assignee: 中兴通讯股份有限公司
Priority date: 2009-05-15
Filing date: 2010-04-07
Publication date: 2010-11-18
Also published as: CN101888360A

Abstract

The present invention discloses a method for transmitting a random access signal, wherein a User Equipment (UE) generates a Cyclic Suffix (CS) of the random access signal according to a random access preamble sequence; the UE inserts the CS between the random access preamble sequence and a Guard Interval (GI), and transmits the random access signal with transmission format sequentially arranged as a Cyclic Prefix (CP), the random access preamble sequence, the CS and the GI. By this means, when the time of the UE is ahead of a base station (Node B), the integrity of the random access signal received by the Node B is guaranteed. In addition, the present invention discloses an apparatus for transmitting the random access signal, and a related method and system, thereby improving the detection performance of the Node B for the random access signal.

Description

Method and device for transmitting random access signal and related method and system

The invention relates to signal processing technology in wireless communication, in particular to an orthogonal frequency division multiplexing

(OFDM, Orthogonal Frequency Division Multiplexing) user terminal in the system

(UE) A method and apparatus for transmitting random access signals and related methods and systems. Background technique

OFDM is actually a type of Multi-Carrier Modulation (MCM). The main idea is: divide the original channel into several orthogonal subchannels, convert the high-speed data signals into parallel low-speed sub-data streams, and modulate them to transmit on each sub-channel, and the orthogonal signals thus formed can pass at the receiving end. Separate by using related techniques, which can reduce mutual interference (ICI) between subchannels. The signal bandwidth on each subchannel is less than its subchannel bandwidth, so the signal waveform on each subchannel can be seen as flat fading, thereby eliminating intersymbol interference. Moreover, since the signal bandwidth on each subchannel is only a small fraction of the original channel bandwidth, channel equalization becomes relatively easy. Therefore, OFDM is one of the key technologies in the evolution of wireless communication systems to B3G/4G. It can combine diversity, space-time coding, interference and inter-channel interference suppression, and intelligent antenna technology to maximize system performance.

As third-generation, third-generation, and future wireless communication systems continue to evolve, wireless communication systems will provide more and more data and more reliable communication quality of service (QOS) guarantees. At the same time, the environment in which the UE is located will become more and more complicated with the advancement of modern technology. High-speed mobile and various multipath reflection conditions determine that the wireless communication system must be able to adapt to these harsh transmission environments. The OFDM system can transform the bandwidth multipath frequency selective channel into a set of convoluted parallel narrowband frequency flatness fading channels, which can effectively eliminate multipath interference, facilitate adaptive data rate adjustment, equalize process, and spectral efficiency. Features that have become the physical layer of future wireless communication systems One of the core transmission technologies.

In the existing OFDM system, the transmission format of the random access signal transmitted by the UE is as shown in FIG. 1 and is composed of three parts, including a cyclic prefix (CP), a random access preamble (RACH preamble), and a guard interval (GI). . For the receiving end base station (Node B ), when the UE transmits the random access signal, the UE first performs the condition that the UE considers to be synchronized with the Node B, but the synchronization may be inaccurate, possibly The time when the UE lags the Node B, and the time of the UE is ahead of the time of the Node B. The transmission format can ensure the detection performance of the random access signal under the premise that the time of the UE lags the Node B. However, when the time of the UE is ahead of the Node B, the UE transmits the signal ahead. Therefore, the random access signal received by the Node B may be missing a part of the data, so that the detection performance of the Node B on the random access signal may be due to the UE at the transmitting end. The signal is transmitted in advance and is seriously affected. Summary of the invention

In view of this, the main object of the present invention is to provide a method and apparatus for transmitting a random access signal and related methods and systems for enhancing the performance of random access signal detection.

In order to achieve the above object, the technical solution of the present invention is achieved as follows:

The present invention provides a method for transmitting a random access signal, the method comprising the following steps: a user terminal UE generates a cyclic suffix of a random access signal according to a random access preamble sequence; the UE adds the cyclic suffix to the random access preamble sequence Between the guard interval and the guard interval, the transmit transmission format is a random access signal of a cyclic prefix, a random access preamble sequence, a cyclic suffix, and a guard interval.

In the foregoing solution, the generating a cyclic suffix according to the random access preamble sequence is: extracting consecutive N ₃ data in the random access preamble sequence as a cyclic suffix, and N ₃ is a positive integer.

In the above solution, the data of the data length N ₃ in the random access preamble sequence is extracted as a cyclic suffix, specifically: extracting the first N ₃ data of the random access preamble sequence, or the last N ₃ data, or any of Continuous N ₃ data as a cyclic suffix. In the foregoing solution, before the generating a cyclic suffix according to the random access preamble sequence, the method further includes: the UE extracting the last data of the random access preamble sequence as a cyclic prefix of the random access signal, and is a positive integer.

In the above solution, after the sending the random access signal including the cyclic prefix, the random access preamble sequence, the cyclic suffix and the guard interval, the method further includes: the base station Node B according to the received cyclic suffix and the random access preamble sequence The phase difference of the data used to generate the cyclic suffix is used for frequency offset estimation.

In the above solution, after performing the frequency offset estimation, the method further comprises: feeding back the value of the frequency offset estimation to the random access signal, and correcting the phase of the random access preamble sequence.

In the above solution, the N _{3 is selected} according to a cell radius and a wireless channel environment.

The present invention provides a transmitting apparatus for a random access signal, the apparatus comprising: a cyclic suffix generating module, and an assembling transmitting module;

a cyclic suffix generating module, configured to extract a cyclic suffix of consecutive N ₃ data in the random access preamble sequence to generate a random access signal;

The transmitting module is configured to sequentially assemble the cyclic prefix, the random access preamble sequence, the cyclic suffix and the guard interval into a random access signal for transmitting.

In the above solution, the apparatus further includes: a random access sequence generating module, a cyclic prefix generating module, and a guard interval generating module;

a random access sequence generating module, configured to generate a random access preamble sequence of the random access signal; a cyclic prefix generating module, configured to extract a cyclic prefix of the random access preamble sequence to generate a random access signal;

A guard interval generation module is configured to generate a guard interval of the random access signal.

The invention provides a method for implementing frequency offset estimation, the method comprising:

The UE generates a cyclic suffix of the random access signal according to the random access preamble sequence; Adding a cyclic suffix between the random access preamble sequence and the guard interval, and transmitting the transmission format into a cyclic prefix, a random access preamble sequence, a cyclic suffix, and a guard interval random access signal;

The Node B obtains the value of the frequency offset estimation based on the phase difference between the received cyclic suffix and the data used to generate the cyclic suffix in the random access preamble sequence.

The present invention provides a system for implementing frequency offset estimation, the system comprising: a UE and a Node B;

The UE is configured to generate a cyclic suffix of the random access signal according to the random access preamble sequence, and add the cyclic suffix between the random access preamble sequence and the guard interval, and send the transmission format into a cyclic prefix, a random access preamble sequence, and Cyclic suffix, guard interval random access signal;

The Node B is configured to perform frequency offset estimation according to a phase difference between the received cyclic suffix and the data used to generate the cyclic suffix in the random access preamble sequence.

The present invention provides a method and apparatus for transmitting a random access signal, and a related method and system. By improving the transmission format of a random access signal of a UE transmitting end, more information can be provided to the Node B, so that the Node B is performing. When the random access signal is detected, the dependence on time is reduced to a certain extent, so that the detection performance of the random access signal does not affect the detection performance of the random access detection system due to the signal transmission being advanced for a certain period of time, and the random connection is enhanced. The reliability of the incoming signal detection. When the time of the UE is ahead of the Node B, it is ensured that the Node B receives the random access signal completely, thereby reducing the impact on the detection performance of the random access signal.

In addition, under high speed conditions, the solution proposed by the present invention facilitates frequency estimation and improves the detection performance of random access signals. DRAWINGS

1 is a schematic diagram of a random access signal transmission format in the existing 36.211 protocol;

2 is a schematic diagram of a transmission process of a random access signal according to the present invention;

3 is a schematic diagram of a random access signal transmission format proposed by the present invention; 4 is a schematic diagram of an apparatus for transmitting random access signals in an OFDM system according to the present invention; and FIG. 5 is a schematic flowchart of a method for implementing frequency offset estimation according to the present invention. The basic idea of the present invention is: the UE generates a cyclic suffix of the random access signal according to the random access preamble sequence; the UE adds the cyclic suffix between the random access preamble sequence and the guard interval, and the transmission transmission format is a loop in turn. Prefix, random access preamble sequence, cyclic suffix, guard interval random access signal.

The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

As shown in FIG. 2, the present invention implements a method for transmitting a random access signal in an orthogonal frequency division multiplexing system, including the following steps:

Step 201: The UE generates a random access preamble sequence.

Let the sequence of generating the random access preamble sequence be " ^W , whose expression is as follows x _u {n)=e ^Nm , 0<n<N _zc -l ( 1 ) where W _zc is the length of the sequence », "=1, N _ZC - 1 , _n is a positive integer.

Then, the random access preamble sequence x(m) of length N ₂ is

Production

x(m) =― JJ x _u (n)-e ^Wzc -e ^N 'Q<m<N ₂ -l ^{2 )}

N ₂

The corresponding time domain discrete signal of the random access preamble sequence 5 (the generation process of 0 is as follows:

S(t) = _PRACH ∑ ∑ x _u (n)-e WW ( 3 ) where Q ≤ t < N ₂ * T _S , where Ts is the reciprocal of the time domain sampling frequency; ^ is the amplitude nominal factor; ^ ^ is the subcarrier spacing of the random access preamble sequence; is the frequency offset of the random access preamble sequence.

Step 202: The UE generates a cyclic prefix according to the random access preamble sequence.

The last data of the random access preamble sequence obtained in step 201 is taken as a cyclic prefix. CP,

which is:

Step 203: The UE generates a cyclic suffix according to the random access preamble sequence.

Specifically, the consecutive N ₃ data of the random access preamble sequence obtained in step 201 can be taken as the cyclic suffix CP1, and the following three methods are available:

1) Take the first N ₃ data of the random access preamble sequence, namely: ' = , = 0,..., N ₃ -1 ( ^{5 )}

2) Take the last N ₃ data of the random access preamble sequence, namely:

CPl _{l =} S _N2 _ _N3+1+l , i = 0,...,N ₃ -l (6)

3) Take any consecutive N ₃ data in the random access preamble sequence, namely:

CP = S _{m+i ?} i = 0,...,N ₃ -l (7)

Where m is an arbitrary integer between 0 and N ₂ -N ₃ +1, N ₃ is a positive integer greater than 0, and the value of N ₃ is related to the cell radius and the wireless channel environment. The larger the cell radius, N ₃ The larger the value should be, the worse the wireless channel should be, and the value of N ₃ should be larger.

Step 204: The UE generates a guard interval.

The guard interval GI is filled with a dummy pad, and the length of the padding dummy is N ₄ .

The above is the generation process of each part of the random access signal. For the convenience of description, the form of the steps is adopted. Actually, the information processing steps of steps 202, 203 and 204 have no obvious time sequence.

Step 205: The UE assembles the data of each part generated in steps 201-204 into a transmission format of a new random access signal, and performs transmission.

The UE assembles the data of each part generated in steps 201-204 into a transmission format as shown in FIG. 3, and the components of the random access signal are: CP, random access preamble sequence, cyclic suffix CP1 and GI.

In this way, when the time of the UE is ahead of the time of the Node B, the transmitted random access signal will be due to The existence of the cyclic suffix adds a certain amount of redundant data, so that when the receiving random access signal is incomplete, the part that the random access preamble is lost can be supplemented with redundant data to achieve effective detection. Random access signal.

In addition, since the cyclic suffix CP1 takes a piece of data in the random access preamble sequence, after the transmission format is determined, the data in the random access preamble sequence obtained by the cyclic suffix is determined, and the UE and the Node B are determined. Both know the length of the loop suffix. After receiving the random access signal in this format, the Node B compares the phase difference between the cyclic suffix and the data obtained by the cyclic suffix in the random access preamble sequence according to the phase difference between the two and the time difference between the two pieces of data. t, the frequency deviation can be calculated, thereby realizing the frequency offset estimation, and the value of the frequency offset estimation is fed back to the random access signal, and the phase of the random access preamble sequence can be corrected, thereby improving the performance of the random access signal detection. .

Through the above method, the present invention provides a transmitting apparatus for implementing a random access signal in an Orthogonal Frequency Division Multiplexing system, and an implementation of the specific application in the OFDM system is as shown in FIG. 4, and the apparatus includes a random access sequence generating module 41. a cyclic prefix generation module 42, a cyclic suffix generation module 43, a guard interval generation module 44, and an assembly transmission module 45, wherein

The random access sequence generating module 41 is configured to generate a random access preamble sequence, specifically: using the expression x(m) = 0<m<N ₂ -l ( ² )

A random access preamble sequence m) having a data length of N ₂ is generated. At the same time, the corresponding time domain discrete signal generation process is generated as follows:

S(t) = _PRACH ∑ ∑ x _u (n).e ^N W where 0 ≤ <N ₂ * , where TS is the reciprocal of the time domain sampling frequency; ^ACH is the amplitude nominal factor; ^^ is random The subcarrier spacing into the preamble sequence; is the frequency offset of the random access preamble sequence. The cyclic prefix generation module 42 utilizes the random generation generated in the random access sequence generation module 41. The last data in the machine access preamble sequence generates a cyclic prefix; the cyclic suffix generation module 43 generates a cyclic suffix by using the consecutive N ₃ data in the random access preamble sequence generated by the random access sequence generation module 41; The module 44 fills the guard interval with the dummy of the data length N ₄ , and sends the data generated by the above modules to the assembly transmitting module 45 , and assembles the transmitting module 45 to assemble the transmission of the random access signal as shown in FIG. 3 . The format is transmitted, that is, the data included in the random access signal is: a cyclic prefix, a random access preamble sequence, a cyclic suffix, and a guard interval.

In addition, the device adds a frequency offset estimation module 46 at the receiving end of the Node B, and the frequency offset estimation module 46 compares the cyclic suffix with the cyclic suffix of the random access preamble sequence by using the random access signal received by the Node B. The phase difference between the data ^ calculates the frequency deviation based on the phase difference S between the two and the time difference t between the two pieces of data, and feeds back the estimated frequency offset to the random access signal to correct the random access preamble The phase of the sequence.

The present invention provides a method for implementing frequency offset estimation by using the method and apparatus for transmitting a random access signal according to the present invention. As shown in FIG. 5, the method includes the following steps:

Step 501: The UE generates a cyclic suffix of the random access signal according to the random access preamble sequence. Step 502: Add a cyclic suffix between the random access preamble sequence and the guard interval, and send the transmission format into a cyclic prefix and a random access preamble. Sequence, cyclic suffix, guard interval random access signal;

Step 503: The Node B performs frequency offset estimation according to the phase difference between the received cyclic suffix and the data used to generate the cyclic suffix in the random access preamble sequence.

Specifically, when the Node B receives the random access signal in this format, the phase difference between the cyclic suffix and the data obtained by the cyclic suffix in the random access preamble is compared according to the phase difference S between the two segments and the two segments. The time difference t between the data gives the frequency deviation, that is, the value of the frequency offset estimate.

The present invention provides a system for implementing frequency offset estimation, using the method and apparatus for transmitting a random access signal according to the present invention, the system comprising: a UE and a Node B; Specifically, the UE generates a cyclic suffix of the random access signal according to the random access preamble sequence, and adds the cyclic suffix between the random access preamble sequence and the guard interval, and the transmission transmission format is a cyclic prefix, a random access preamble sequence, The cyclic suffix, the guard interval random access signal to the Node B; the phase difference between the cyclic suffix received by the Node B and the data used to generate the cyclic suffix in the random access preamble sequence, and the frequency deviation is calculated to obtain the value of the frequency offset estimation. The system is further configured to: feed back the value of the frequency offset estimate to the random access signal, and correct the phase of the random access preamble 歹'J.

It can be seen that, by using the foregoing method and device for transmitting random access signals, due to the existence of a cyclic suffix, a certain amount of redundant data is added, so that the Node B can use redundant data when performing random access signal detection. The complete random access signal is supplemented, so that the dependence of the Node B on time is reduced to a certain extent, so that the detection performance of the random access signal does not affect the random access signal detection system due to the signal transmission being advanced by a certain period of time. The detection performance enhances the reliability of the Node B for detecting random access signals. In addition, under high-speed conditions, the correlation system of the random access signal proposed by the present invention is helpful for frequency estimation, and the value of the frequency offset estimation is fed back to the random access signal, which is beneficial to improving the random access signal of the Node B. Detection performance.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included. Within the scope of protection of the present invention.

Claims

Claim

A method for transmitting a random access signal, the method comprising the steps of: generating, by a user terminal UE, a cyclic suffix of a random access signal according to a random access preamble sequence; the UE adding the cyclic suffix to the random access Between the preamble sequence and the guard interval, the transmit transmission format is a random access signal of a cyclic prefix, a random access preamble sequence, a cyclic suffix, and a guard interval.

The method according to claim 1, wherein the generating a cyclic suffix according to the random access preamble sequence is: extracting consecutive N ₃ data in the random access preamble sequence as a cyclic suffix, and N ₃ is positive Integer.

3. The method of claim 2, wherein the random access preamble sequence to extract the data length of the data as the cyclic suffix N _3, specifically:

The previous data of the random access preamble sequence, or the last data, or any consecutive N ₃ data is extracted as a cyclic suffix.

The method according to claim 1, wherein before the generating a cyclic suffix according to the random access preamble sequence, the method further comprises: the UE extracting the last data of the random access preamble sequence as a random access signal. The cyclic prefix is a positive integer.

The method according to any one of claims 1 to 4, wherein after the transmitting the random access signal including the cyclic prefix, the random access preamble sequence, the cyclic suffix and the guard interval, the method further comprises: The Node B performs frequency offset estimation based on the phase difference between the received cyclic suffix and the data used to generate the cyclic suffix in the random access preamble sequence.

The method according to claim 5, wherein after the performing the frequency offset estimation, the method further comprises: feeding back the value of the frequency offset estimation to a random access signal, and modifying the random access The phase of the preamble sequence.

7. A method according to claim 2 or claim 3, wherein the N ₃ be selected according to the cell radius and the radio channel environment.

A transmitting device for randomly accessing a signal, wherein the device comprises: a cyclic suffix generating module and an assembled transmitting module; wherein

The apparatus according to claim 8, wherein the apparatus further comprises: a random access sequence generating module, a cyclic prefix generating module, and a guard interval generating module; wherein, the random access sequence generating module is configured to generate a random a random access preamble sequence of the access signal; a cyclic prefix generation module, configured to extract a cyclic prefix of the random access signal generated by the latter data in the random access preamble sequence;

A method for implementing frequency offset estimation, the method comprising: generating, by a UE, a cyclic suffix of a random access signal according to a random access preamble sequence;

The cyclic suffix is added between the random access preamble sequence and the guard interval, and the transmission format is a cyclic prefix, a random access preamble sequence, a cyclic suffix, and a guard interval random access signal;

A system for implementing frequency offset estimation, the system comprising: a UE and a Node B;

Node B, used to generate according to the received cyclic suffix and the random access preamble sequence The phase difference of the data of the cyclic suffix, and the frequency offset estimation ₍