WO2008035955A2 - Method for multiplexing user equipment signals having different bandwidth, and method for transmitting uplink signal - Google Patents

Method for multiplexing user equipment signals having different bandwidth, and method for transmitting uplink signal Download PDF

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Publication number
WO2008035955A2
WO2008035955A2 PCT/KR2007/004675 KR2007004675W WO2008035955A2 WO 2008035955 A2 WO2008035955 A2 WO 2008035955A2 KR 2007004675 W KR2007004675 W KR 2007004675W WO 2008035955 A2 WO2008035955 A2 WO 2008035955A2
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Prior art keywords
basic
sequences
bandwidth
sequence
user equipments
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PCT/KR2007/004675
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French (fr)
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WO2008035955A3 (en
Inventor
Min Seok Noh
Seung Hee Han
Yeong Hyeon Kwon
Hyun Hwa Park
Hyun Woo Lee
Dong Cheol Kim
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Lg Electronics Inc.
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Publication of WO2008035955A2 publication Critical patent/WO2008035955A2/en
Publication of WO2008035955A3 publication Critical patent/WO2008035955A3/en

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J13/00—Code division multiplex systems
    • H04J13/16—Code allocation
    • H04J13/18—Allocation of orthogonal codes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J13/00—Code division multiplex systems
    • H04J13/0074—Code shifting or hopping
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/0001—Arrangements for dividing the transmission path
    • H04L5/0003—Two-dimensional division
    • H04L5/0005—Time-frequency
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0037—Inter-user or inter-terminal allocation
    • H04L5/0039—Frequency-contiguous, i.e. with no allocation of frequencies for one user or terminal between the frequencies allocated to another
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0058—Allocation criteria
    • H04L5/0064—Rate requirement of the data, e.g. scalable bandwidth, data priority
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J13/00—Code division multiplex systems
    • H04J13/0007—Code type
    • H04J13/0055—ZCZ [zero correlation zone]
    • H04J13/0059—CAZAC [constant-amplitude and zero auto-correlation]
    • H04J13/0062—Zadoff-Chu
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/0001—Arrangements for dividing the transmission path
    • H04L5/0014—Three-dimensional division
    • H04L5/0016—Time-frequency-code
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver

Definitions

  • the present invention relates to a communication system, and more particularly, to a method for multiplexing user equipment s ignals having dif ferent bandwidths , and a method for transmitting uplink s ignal s .
  • 3GPP LTE system it is considered that two reference signals or pilot blocks are used in an uplink. If user equipments (UEs) which exist within one system, i.e., a single cell or sector, have the same bandwidth, the 3GPP LTE system considers a CDM scheme, an FDM scheme, and a hybrid CDM and FDM scheme to identify the pilots.
  • UEs user equipments
  • each user equipment multiplies its transmitting signal by a predetermined sequence and then transmits the resultant signal to a base station through an uplink.
  • the base station which has received the signal identifies signals of the respective user equipments by using the sequence multiplied by the transmitting signal.
  • CAZAC sequences are used as follows. Two types of CAZAC sequences, i.e., GCL CAZAC sequence and Zadoff-Chu CAZAC sequence are mainly used as the CAZAC sequences. The two types of CAZAC sequences are associated with each other by a conjuqate complex relation.
  • the GCL CAZAC sequence can be acquired by conjugate complex calculation for the Zadoff-Chu CAZAC sequence.
  • the Zadoff-Chu CAZAC sequence is given as follows. [Equation 1]
  • the Equation 3 means that the CAZAC sequence always has a size of 1, and the Equation 4 shows that an auto-correlation function of the CAZAC sequence is expressed by a delta function. In this case, the auto-correlation is based on circular correlation. Also, the Equation 5 shows that a cross- correlation is always a constant. Meanwhile, since several user equipments (UEs) exist within one base station or one sector in the uplink, it is necessary to identify each of the user equipments (UEs) . If the CDM scheme is applied to the user equipments having the same transmission bandwidth in a conventional system which uses the CAZAC sequence, a method for applying circular shift to the CAZAC sequence is used to identify pilots of the user equipments. In other words, if N number of user equipments
  • pilots of the respective user equipments are multiplexed by applying circular shift to the sequence using a shift value of a length L/N obtained by dividing a length L of the sequence by the number N of user equipments (UEs) .
  • a method of applying circular shift to the sequence is disclosed in "code sequence in a communication system and method and apparatus for transmitting and generating the same" (Patent Application No. 2006-64091) invented by the inventor of this application and filed by the applicant of this application.
  • the CAZAC sequence to which circular shift is applied as described above is used based on characteristics that zero cross correlation is maintained between CAZAC sequences to which circular shift of different levels is applied.
  • the relation that zero cross correlation is maintained is called that it has "orthogonality."
  • the aforementioned CDM scheme has a problem in that orthogonality is not maintained between sequences having different bandwidths, i.e., sequences having different lengths, due to characteristics of the CAZAC sequences, when multiplexing is performed between the user equipments having different bandwidths.
  • the aforementioned pilot blocks should be identified to maintain orthogonality between the user equipments. If orthogonality is removed, degradation due to channel estimation is caused, thereby leading to limitation of performance. Accordingly, a new method for applying the CDM scheme to the user equipments having different bandwidths is required.
  • DoCoMo has suggested a distributive FDMA scheme as follows to identify pilots of different bandwidths.
  • FIG. 1 illustrates a method for multiplexing signals of user equipments (UEs) having different bandwidths in an FDM scheme.
  • UEs user equipments
  • FIG. 1 illustrates that user equipments having transmission bandwidths of 1.25 MHz, 5 MHz, and 10 MHz exist within one cell, or one sector on one system.
  • the respective user equipments having different bandwidths such as 1.25 MHz, 5 MHz, and 10 MHz within an entire band of 10 MHz which are available to the user equipments can be identified by different frequency bands on a frequency axis in a distributed FDMA scheme.
  • a multiplexing method is used in a CDM scheme which uses different original sequences (for example, CAZAC #1,
  • the FDM scheme may have the following problem.
  • FIG. 2 illustrates that each user transmits a separate pilot in an FDM scheme so as to measure channel quality of a band to which user data are not transmitted.
  • each user equipment (each of the user equipments having different bandwidths in the aforementioned example) is allocated with its frequency band among frequency bands allocated to the user equipments which use corresponding bandwidths, and transmits data to the frequency band. Also, each user equipment transmits a separate pilot (for example, CQ pilot) for measuring channel quality to the other frequency bands (out-band) .
  • CQ pilot for example, CQ pilot
  • pilot signals of the respective user equipments can be identified by code sequence, and pilots are allocated to all available bands of the user equipments other than the frequency band allocated to the user equipments in the CDM scheme. Accordingly, since CQ pilot for checking quality of a channel which is not used is not required, it is advantageous in that overhead can be reduced.
  • FIG. 3 illustrates a possibility of interference between cells in the FDM scheme.
  • interference may occur between uplink signals of these user equipments.
  • signal interference between adjacent cells may not be excluded completely even in case of the CDM scheme.
  • signal interference from adjacent cells is not fatal unlike signal interference in a specific bandwidth of the FDM scheme.
  • the CDM scheme is advantageous in that interference between adjacent cells can easily be solved through a method for differently allocating sequences for identifying user equipments in each cell.
  • error may occur due to poor channel status in a specific frequency band in case of the FDM scheme.
  • a technique for multiplexing signals of user equipments having different bandwidths while maintaining a CDM scheme is required.
  • the present invention is directed to a method for multiplexing user equipment signals having different bandwidths and a method for transmitting uplink signals, which substantially obviate one or more problems due to limitations and disadvantages of the related art.
  • An object of the present invention is to provide a multiplexing method for allowing a base station to easily identify uplink signals of user equipments having different bandwidths while maintaining a CDM scheme.
  • Another object of the present invention is to provide a method for transmitting uplink signals from user equipments to perform multiplexing.
  • a multiplexing method includes setting a bandwidth corresponding to a common measure of bandwidths which a plurality of user equipments respectively use, as a basic bandwidth, selecting basic sequences corresponding to the basic bandwidth to perform signal multiplexing of the plurality of user equipments, and performing multiplexing using a sequence obtained by repeating the basic sequences in case of a signal of a user equipment, which uses a bandwidth more than the basic bandwidth, among the plurality of user equipments .
  • the number of repetition times of the basic sequence in the multiplexing step corresponds to a number obtained by dividing the bandwidth of the user equipment, which uses a bandwidth more than the basic bandwidth, by the basic bandwidth.
  • the basic sequences selected in the selecting step of the basic sequences corresponding to the basic bandwidth are different original sequences, orthogonal sequences having mutual orthogonality, obtained by applying different circular shifts to the same original sequence, and sequences selected from a group consisting of combination of the original sequences and the orthogonal sequences.
  • a method for transmitting uplink signals from a user equipment includes selecting a predetermined sequence as a transmitting signal, and transmitting the selected predetermined sequence through an uplink, wherein the predetermined sequence is a sequence obtained by repeating basic sequences if a bandwidth which the user equipment uses is wider than that of the basic sequences.
  • the basic sequences are sequences having a bandwidth corresponding to a common measure of bandwidths of a plurality of user equipments which are provided with services by the same base station as that of the user equipment.
  • the basic sequences are different original sequences, orthogonal sequences having mutual orthogonality, obtained by applying different circular shifts to the same original sequence, and sequences selected from a group consisting of combination of the original sequences and the orthogonal sequences .
  • a method for identifying signals includes receiving uplink signals, and checking whether the received signals have been transmitted from which user equipment through a predetermined sequence used in the received signals, wherein the predetermined sequence is a basic sequence having a basic bandwidth corresponding to a common measure of bandwidths of a plurality of user equipments which are provided with services by a base station .
  • the plurality of user equipments set a bandwidth corresponding to a common measure of different transmission bandwidths as a basic bandwidth, and select a basic sequence applied to the basic bandwidth to repeatedly use the basic sequence to be equivalent to a bandwidth of a corresponding user equipment, thereby maintaining orthogonality even in case that sequences used for multiplexing are different from one another in their length.
  • the base station can easily identify whether received uplink signals have been transmitted from which user equipment, while maintaining a CDM scheme as a multiplexing scheme.
  • the user equipment can implement multiplexing of the CDM scheme according to the present invention by transmitting signals in accordance with the aforementioned method for transmitting uplink signals.
  • FIG. 1 illustrates a method for multiplexing signals of user equipments (UEs) having different bandwidths in an FDM scheme
  • FIG. 2 illustrates that each user transmits a separate pilot in an FDM scheme so as to measure channel quality of a band to which user data are not transmitted;
  • FIG. 3 illustrates a possibility of interference between cells in an FDM scheme
  • FIG. 4 and FIG. 5 illustrate a multiplexing scheme between user equipments having different bandwidths in accordance with the preferred embodiment of the present invention.
  • FIG. 6 is a flow chart illustrating a method for transmitting uplink signals from user equipments in accordance with the preferred embodiment of the present invention.
  • the present invention relates to a method for multiplexing reference signals between user equipments and reference signals for identifying pilots and a method for transmitting uplink signals, even in case that user equipments existing on a system have different transmission bandwidths.
  • a method for setting a basic transmission bandwidth based on a common measure of different transmission bandwidths allocating CAZAC sequence length as a basic sequence length, and transmitting a repetitive sequence to user equipments having transmission bandwidths greater than the basic transmission bandwidth. This method will be described in detail with reference to FIG. 4 and FIG. 5.
  • FIG. 4 and FIG. 5 illustrate a multiplexing scheme between user equipments having different bandwidths in accordance with the preferred embodiment of the present invention.
  • FIG. 4 illustrates an example that user equipments (UEs) having a transmission bandwidth of 1.25 MHz, user equipments having a transmission bandwidth of 5 MHz, and user equipments having a transmission bandwidth of 10 MHz exist.
  • UEs user equipments
  • a common measure of three different bandwidths most preferably the greatest common measure of 1.25 MHz is regarded as a basic transmission bandwidth, and a CAZAC sequence based on the greatest common measure of 1.25 MHz can be generated as a basic sequence.
  • the basic transmission band may be set by a random bandwidth corresponding to a common measure of the different bandwidths of the user equipments, if a sequence is applied to a narrow bandwidth, the number of orthogonal sequences, to which circular shift can be applied with maintaining orthogonality, can be reduced. In this respect, it is preferable that the aforementioned bandwidth corresponding to the greatest common measure is set.
  • one CAZAC sequence index is selected to select an original sequence for multiplexing a signal of a corresponding user equipment.
  • circular shift versions in which predetermined circular shift is applied to the CAZAC sequence of the selected index, i.e., another types of CAZAC sequence shift #1, CAZAC sequence shift #2,... are selected.
  • the sequences to which circular shift is applied should mutually be maintained with orthogonality.
  • the user equipment which has selected the basic sequence having the basic transmission bandwidth length configures the basic sequence as a sequence for CDM by taking a repetitive sequence suitable for its transmission bandwidth.
  • the user equipment having a bandwidth of 5 MHz configures a sequence obtained by repeating CAZAC sequence shift #2 four times as a sequence for CDM, wherein the CAZAC sequence shift #2 is selected as the basic sequence having the basic transmission bandwidth length of 1.25 MHz.
  • the user equipment having a bandwidth of 10 MHz configures a sequence obtained by repeating CAZAC sequence shift #3 eight times as a sequence for CDM, wherein the CAZAC sequence shift #3 is selected as the basic sequence.
  • a method for identifying uplink signals in a base station in accordance with the preferred embodiment of the present invention includes receives signals from a plurality of user equipments to identify through a sequence used in each signal whether the signals have been received from which user equipment. According to this method, user equipments which have transmitted signals can be identified through which one of the aforementioned basic sequences, i.e., the basic sequences having a bandwidth corresponding to a common measure of a plurality of user equipments, has been used.
  • FIG. 5 illustrates an example that user equipments having a transmission bandwidth of 10 MHz and user equipments having a transmission bandwidth of 15 MHz exist in case of an entire transmission bandwidth of 20 MHz.
  • a common measure of two different bandwidths most preferably the greatest common measure of 5 MHz is regarded as a basic transmission bandwidth, and a CAZAC sequence based on the greatest common measure of 1.25 MHz is generated.
  • one CAZAC sequence index of several sequence indexes having the basic bandwidth length determined as above is selected.
  • circular shift versions in which predetermined circular shift is applied to the CAZAC sequence of the selected index i.e., another types of CAZAC sequence shift #1, CAZAC sequence shift #2,... are selected.
  • Corresponding user equipments can configure a code sequence to be used for CDM by taking a repetitive sequence suitable for their transmission bandwidths .
  • the base station since the base station receives circular shifted CAZAC sequence of 5 MHz, it can multiplex reference signals or pilots of user equipments having different transmission bandwidths.
  • uplink signals of the user equipments can be identified with maintaining orthogonality by setting a CAZAC sequence having a length corresponding to a common measure of the different time lengths as a basic sequence and allowing each user equipment to repeatedly use the CAZAC sequence in accordance with a time length of a sequence used for CDM.
  • the repetitive scheme of the CAZAC sequence can be implemented by direct repetitive insertion in a time domain/frequency domain.
  • the CAZAC sequence can be generated as a repetitive sequence by a predetermined processing procedure in domains different from the repetitive time domain/frequency domain.
  • FIG. 6 is a flow chart illustrating a method for transmitting uplink signals from user equipments in accordance with the preferred embodiment of the present invention.
  • the user equipment selects basic sequences to be used for its uplink signal multiplexing in step S601.
  • the basic sequences are selected from different original sequences such as CAZAC sequences having different IDs, orthogonal sequences having mutual orthogonality by applying different circular shifts to the same original sequence, and a group consisting of combination of the original sequences and the orthogonal sequences, and represent sequences having the basic bandwidth described with reference to FIG. 4 and FIG. 5.
  • FIG. 4 and FIG. 5 is defined in a specific communication system
  • the corresponding communication system can previously set the aforementioned basic frequency band and the basic sequences considering bandwidths of the user equipments.
  • each user equipment can select a sequence for its multiplexing among the basic sequences previously set in the communication system when transmitting uplink signals.
  • the user equipment checks whether its frequency bandwidth is wider than the aforementioned basic frequency band in step S602. If the frequency bandwidth of the user equipment is wider than the basic frequency band, the current step advances to step S603 so that the user equipment repeats the basic sequence selected in step S601 to have its bandwidth length and configures the repeated sequence as CDM signal in step S604.
  • This CDM signal could be a repetitive sequence, for example, a repetitive type CAZAC sequence if a transmitting signal is a pilot signal. Also, if a transmitting signal is specific data, the CDM signal could be a type obtained by multiplying the repetitive type CAZAC sequence by the corresponding data. Afterwards, the CDM signal generated as above is transmitted through step S606.
  • the current step advances to step S605.
  • the user equipment generates a CDM signal by using the basic sequence in the transmitting signal as it is, and transmits the generated CDM signal to an uplink through step S606.
  • the generated CDM signal could be the basic sequence if the transmitting signal is a pilot.
  • the generated CDM signal could be a type obtained by multiplying the basic sequence by the data.
  • a plurality of user equipments set a bandwidth corresponding to a common measure of different transmission bandwidths as a basic bandwidth, and select basic sequences applied to the basic bandwidth to repeatedly use the basic sequences to be equivalent to a bandwidth of a corresponding user equipment, thereby maintaining orthogonality even in case that sequences used for multiplexing are different from one another in their length.
  • the base station can easily identify whether received uplink signals have been transmitted from which user equipment, while maintaining a CDM scheme as a multiplexing scheme.
  • the user equipment can implement multiplexing of the CDM scheme according to the present invention by transmitting signals in accordance with the aforementioned method for transmitting uplink signals.
  • the aforementioned method according to the present invention can be applied to a random communication system as well as 3GPP LTE system.

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Abstract

Disclosed are a method for multiplexing user equipment signals having different bandwidths and methods for transmitting and identifying uplink signals. One of said methods includes setting a bandwidth corresponding to a common measure of bandwidths which a plurality of user equipments (UEs) respectively use, as a basic bandwidth, selecting basic sequences corresponding to the basic bandwidth to perform signal multiplexing of the plurality of UEs, and performing multiplexing using a sequence obtained by repeating the basic sequences in case of a signal of a UE, which uses a bandwidth more than the basic bandwidth, among the plurality of UEs.

Description

METHOD FOR MULTIPLEXING UE SIGNALS HAVING DIFFERENT BANDWIDTH, AND METHOD FOR TRANSMITTING UPLINK SIGNAL
[DESCRIPTION] TECHNICAL FIELD
The present invention relates to a communication system, and more particularly, to a method for multiplexing user equipment s ignals having dif ferent bandwidths , and a method for transmitting uplink s ignal s .
BACKGROUND ART
In 3GPP LTE system, it is considered that two reference signals or pilot blocks are used in an uplink. If user equipments (UEs) which exist within one system, i.e., a single cell or sector, have the same bandwidth, the 3GPP LTE system considers a CDM scheme, an FDM scheme, and a hybrid CDM and FDM scheme to identify the pilots.
In case of the CDM scheme, each user equipment multiplies its transmitting signal by a predetermined sequence and then transmits the resultant signal to a base station through an uplink. The base station which has received the signal identifies signals of the respective user equipments by using the sequence multiplied by the transmitting signal. In such a CDM scheme, it is general that CAZAC sequences are used as follows. Two types of CAZAC sequences, i.e., GCL CAZAC sequence and Zadoff-Chu CAZAC sequence are mainly used as the CAZAC sequences. The two types of CAZAC sequences are associated with each other by a conjuqate complex relation. The GCL CAZAC sequence can be acquired by conjugate complex calculation for the Zadoff-Chu CAZAC sequence. The Zadoff-Chu CAZAC sequence is given as follows. [Equation 1]
c(K;N,M) = eχp(JπMk{k + l) (for odd N)
N [ Equation 2 ]
c(K;N,M) = exp(JπM ( for even N ) N where k represents a sequence index, N represents a length of CAZAC sequence to be generated, and M represents sequence ID. When the Zadoff-Chu CAZAC sequence given by the Equations 1 and 2 and the GCL CAZAC sequence which is a conjugate complex relation with the Zadoff-Chu CAZAC sequence are represented by c(k;N,M), three features are obtained as follows . [Equation 3]
Figure imgf000004_0001
[Equation 4]
Figure imgf000005_0001
[ Equat ion 5 ]
RMI , M2 ,- N ( d ) =p ( for a l l Mi , M2 and N )
The Equation 3 means that the CAZAC sequence always has a size of 1, and the Equation 4 shows that an auto-correlation function of the CAZAC sequence is expressed by a delta function. In this case, the auto-correlation is based on circular correlation. Also, the Equation 5 shows that a cross- correlation is always a constant. Meanwhile, since several user equipments (UEs) exist within one base station or one sector in the uplink, it is necessary to identify each of the user equipments (UEs) . If the CDM scheme is applied to the user equipments having the same transmission bandwidth in a conventional system which uses the CAZAC sequence, a method for applying circular shift to the CAZAC sequence is used to identify pilots of the user equipments. In other words, if N number of user equipments
(UE) exist, pilots of the respective user equipments are multiplexed by applying circular shift to the sequence using a shift value of a length L/N obtained by dividing a length L of the sequence by the number N of user equipments (UEs) . In more detail, a method of applying circular shift to the sequence is disclosed in "code sequence in a communication system and method and apparatus for transmitting and generating the same" (Patent Application No. 2006-64091) invented by the inventor of this application and filed by the applicant of this application.
The CAZAC sequence to which circular shift is applied as described above is used based on characteristics that zero cross correlation is maintained between CAZAC sequences to which circular shift of different levels is applied. The relation that zero cross correlation is maintained is called that it has "orthogonality." In the current 3GPP LTE, it is being discussed that user equipments use different bandwidths . In this respect, the aforementioned CDM scheme has a problem in that orthogonality is not maintained between sequences having different bandwidths, i.e., sequences having different lengths, due to characteristics of the CAZAC sequences, when multiplexing is performed between the user equipments having different bandwidths. Also, among uplink signals, particularly the aforementioned pilot blocks should be identified to maintain orthogonality between the user equipments. If orthogonality is removed, degradation due to channel estimation is caused, thereby leading to limitation of performance. Accordingly, a new method for applying the CDM scheme to the user equipments having different bandwidths is required.
In this respect, if the user equipments which exist in the system have different bandwidths, DoCoMo has suggested a distributive FDMA scheme as follows to identify pilots of different bandwidths.
FIG. 1 illustrates a method for multiplexing signals of user equipments (UEs) having different bandwidths in an FDM scheme.
For example, FIG. 1 illustrates that user equipments having transmission bandwidths of 1.25 MHz, 5 MHz, and 10 MHz exist within one cell, or one sector on one system. In this case, the respective user equipments having different bandwidths such as 1.25 MHz, 5 MHz, and 10 MHz within an entire band of 10 MHz which are available to the user equipments can be identified by different frequency bands on a frequency axis in a distributed FDMA scheme. Also, within transmission bands of user equipments having the same bandwidth, a multiplexing method is used in a CDM scheme which uses different original sequences (for example, CAZAC #1,
CAZAC #2, etc.) and orthogonal sequences (for example, CAZAC
#1, shift #1 to CAZAC #1, shift #N) having different levels of circular shift in the same original sequence. However, the FDM scheme may have the following problem.
FIG. 2 illustrates that each user transmits a separate pilot in an FDM scheme so as to measure channel quality of a band to which user data are not transmitted.
In case of the FDM scheme, each user equipment (each of the user equipments having different bandwidths in the aforementioned example) is allocated with its frequency band among frequency bands allocated to the user equipments which use corresponding bandwidths, and transmits data to the frequency band. Also, each user equipment transmits a separate pilot (for example, CQ pilot) for measuring channel quality to the other frequency bands (out-band) . This is because that signal transmission can be performed through a frequency band other than the current frequency band if channel quality of the frequency band other than the current frequency band is more excellent than that of the current frequency band. CQ pilot transmission to all the frequency bands other than the current frequency band may be regarded as overhead, which is not desirable. On the other hand, in case of the CDM scheme, pilot signals of the respective user equipments can be identified by code sequence, and pilots are allocated to all available bands of the user equipments other than the frequency band allocated to the user equipments in the CDM scheme. Accordingly, since CQ pilot for checking quality of a channel which is not used is not required, it is advantageous in that overhead can be reduced.
FIG. 3 illustrates a possibility of interference between cells in the FDM scheme.
In the multiplexing method of the FDM scheme, if user equipments (for example, UE a of a cell A and UE b of a cell B) which use the same frequency band exist in adjacent cells A and B in FIG. 3, interference may occur between uplink signals of these user equipments. Of course, signal interference between adjacent cells may not be excluded completely even in case of the CDM scheme. However, in case of the CDM scheme which uses entire bandwidths available within cells, signal interference from adjacent cells is not fatal unlike signal interference in a specific bandwidth of the FDM scheme. The CDM scheme is advantageous in that interference between adjacent cells can easily be solved through a method for differently allocating sequences for identifying user equipments in each cell.
In addition, error may occur due to poor channel status in a specific frequency band in case of the FDM scheme. In this respect, a technique for multiplexing signals of user equipments having different bandwidths while maintaining a CDM scheme is required.
DISCLOSURE OF THE INVENTION
Accordingly, the present invention is directed to a method for multiplexing user equipment signals having different bandwidths and a method for transmitting uplink signals, which substantially obviate one or more problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide a multiplexing method for allowing a base station to easily identify uplink signals of user equipments having different bandwidths while maintaining a CDM scheme.
Another object of the present invention is to provide a method for transmitting uplink signals from user equipments to perform multiplexing.
To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a multiplexing method according to the present invention includes setting a bandwidth corresponding to a common measure of bandwidths which a plurality of user equipments respectively use, as a basic bandwidth, selecting basic sequences corresponding to the basic bandwidth to perform signal multiplexing of the plurality of user equipments, and performing multiplexing using a sequence obtained by repeating the basic sequences in case of a signal of a user equipment, which uses a bandwidth more than the basic bandwidth, among the plurality of user equipments .
In this case, the number of repetition times of the basic sequence in the multiplexing step , corresponds to a number obtained by dividing the bandwidth of the user equipment, which uses a bandwidth more than the basic bandwidth, by the basic bandwidth. The basic sequences selected in the selecting step of the basic sequences corresponding to the basic bandwidth are different original sequences, orthogonal sequences having mutual orthogonality, obtained by applying different circular shifts to the same original sequence, and sequences selected from a group consisting of combination of the original sequences and the orthogonal sequences.
In another aspect of the present invention, a method for transmitting uplink signals from a user equipment includes selecting a predetermined sequence as a transmitting signal, and transmitting the selected predetermined sequence through an uplink, wherein the predetermined sequence is a sequence obtained by repeating basic sequences if a bandwidth which the user equipment uses is wider than that of the basic sequences.
In this case, the basic sequences are sequences having a bandwidth corresponding to a common measure of bandwidths of a plurality of user equipments which are provided with services by the same base station as that of the user equipment. Also, the basic sequences are different original sequences, orthogonal sequences having mutual orthogonality, obtained by applying different circular shifts to the same original sequence, and sequences selected from a group consisting of combination of the original sequences and the orthogonal sequences .
In other aspect of the present invention, a method for identifying signals includes receiving uplink signals, and checking whether the received signals have been transmitted from which user equipment through a predetermined sequence used in the received signals, wherein the predetermined sequence is a basic sequence having a basic bandwidth corresponding to a common measure of bandwidths of a plurality of user equipments which are provided with services by a base station .
According to the preferred embodiment of the present invention, the plurality of user equipments set a bandwidth corresponding to a common measure of different transmission bandwidths as a basic bandwidth, and select a basic sequence applied to the basic bandwidth to repeatedly use the basic sequence to be equivalent to a bandwidth of a corresponding user equipment, thereby maintaining orthogonality even in case that sequences used for multiplexing are different from one another in their length. As a result, the base station can easily identify whether received uplink signals have been transmitted from which user equipment, while maintaining a CDM scheme as a multiplexing scheme.
In addition, the user equipment can implement multiplexing of the CDM scheme according to the present invention by transmitting signals in accordance with the aforementioned method for transmitting uplink signals.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a method for multiplexing signals of user equipments (UEs) having different bandwidths in an FDM scheme;
FIG. 2 illustrates that each user transmits a separate pilot in an FDM scheme so as to measure channel quality of a band to which user data are not transmitted;
FIG. 3 illustrates a possibility of interference between cells in an FDM scheme;
FIG. 4 and FIG. 5 illustrate a multiplexing scheme between user equipments having different bandwidths in accordance with the preferred embodiment of the present invention; and
FIG. 6 is a flow chart illustrating a method for transmitting uplink signals from user equipments in accordance with the preferred embodiment of the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It is to be understood that the detailed description which will be disclosed along with the accompanying drawings is intended to describe the exemplary embodiments of the present invention, and is not intended to describe a unique embodiment which the present invention can be carried out. Hereinafter, the detailed description includes detailed matters to provide full understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention can be carried out without the detailed matters. To prevent the concept of the present invention from being ambiguous, structures and apparatuses of the known art will be omitted, or will be shown in the form of a block diagram based on main functions of each structure and apparatus. Also, wherever possible, the same reference numbers will be used throughout the drawings and the specification to refer to the same or like parts. The present invention relates to a method for multiplexing reference signals between user equipments and reference signals for identifying pilots and a method for transmitting uplink signals, even in case that user equipments existing on a system have different transmission bandwidths. To this end, if user equipments which exist within one cell or one sector have different transmission bandwidths, there is suggested a method for setting a basic transmission bandwidth based on a common measure of different transmission bandwidths, allocating CAZAC sequence length as a basic sequence length, and transmitting a repetitive sequence to user equipments having transmission bandwidths greater than the basic transmission bandwidth. This method will be described in detail with reference to FIG. 4 and FIG. 5.
FIG. 4 and FIG. 5 illustrate a multiplexing scheme between user equipments having different bandwidths in accordance with the preferred embodiment of the present invention.
First of all, FIG. 4 illustrates an example that user equipments (UEs) having a transmission bandwidth of 1.25 MHz, user equipments having a transmission bandwidth of 5 MHz, and user equipments having a transmission bandwidth of 10 MHz exist. In other words, for user equipments having three different transmission bandwidths of 1.25 MHz, 5 MHz, and 10 MHz, a common measure of three different bandwidths, most preferably the greatest common measure of 1.25 MHz is regarded as a basic transmission bandwidth, and a CAZAC sequence based on the greatest common measure of 1.25 MHz can be generated as a basic sequence. According to the preferred embodiment of the present invention, although the basic transmission band may be set by a random bandwidth corresponding to a common measure of the different bandwidths of the user equipments, if a sequence is applied to a narrow bandwidth, the number of orthogonal sequences, to which circular shift can be applied with maintaining orthogonality, can be reduced. In this respect, it is preferable that the aforementioned bandwidth corresponding to the greatest common measure is set.
According to the preferred embodiment of the present invention, among several sequence indexes having the basic frequency band length determined as above, one CAZAC sequence index is selected to select an original sequence for multiplexing a signal of a corresponding user equipment. Afterwards, circular shift versions in which predetermined circular shift is applied to the CAZAC sequence of the selected index, i.e., another types of CAZAC sequence shift #1, CAZAC sequence shift #2,... are selected. Of course, the sequences to which circular shift is applied should mutually be maintained with orthogonality.
As described above, the user equipment which has selected the basic sequence having the basic transmission bandwidth length configures the basic sequence as a sequence for CDM by taking a repetitive sequence suitable for its transmission bandwidth. For example, the user equipment having a bandwidth of 5 MHz configures a sequence obtained by repeating CAZAC sequence shift #2 four times as a sequence for CDM, wherein the CAZAC sequence shift #2 is selected as the basic sequence having the basic transmission bandwidth length of 1.25 MHz. The user equipment having a bandwidth of 10 MHz configures a sequence obtained by repeating CAZAC sequence shift #3 eight times as a sequence for CDM, wherein the CAZAC sequence shift #3 is selected as the basic sequence.
In this case, when a base station receives uplink signals, the signals of all user equipments may be regarded as circular shifted CAZAC sequence having a length of 1.25 MHz. Accordingly, the base station can multiplex reference signals or pilots of the user equipments having different transmission bandwidths without maintaining orthogonality. In other words, a method for identifying uplink signals in a base station in accordance with the preferred embodiment of the present invention includes receives signals from a plurality of user equipments to identify through a sequence used in each signal whether the signals have been received from which user equipment. According to this method, user equipments which have transmitted signals can be identified through which one of the aforementioned basic sequences, i.e., the basic sequences having a bandwidth corresponding to a common measure of a plurality of user equipments, has been used.
Next, FIG. 5 illustrates an example that user equipments having a transmission bandwidth of 10 MHz and user equipments having a transmission bandwidth of 15 MHz exist in case of an entire transmission bandwidth of 20 MHz. In other words, for user equipments having two different transmission bandwidths of 10 MHz and 15 MHz, a common measure of two different bandwidths, most preferably the greatest common measure of 5 MHz is regarded as a basic transmission bandwidth, and a CAZAC sequence based on the greatest common measure of 1.25 MHz is generated.
Also, one CAZAC sequence index of several sequence indexes having the basic bandwidth length determined as above is selected. Afterwards, circular shift versions in which predetermined circular shift is applied to the CAZAC sequence of the selected index, i.e., another types of CAZAC sequence shift #1, CAZAC sequence shift #2,... are selected. Corresponding user equipments can configure a code sequence to be used for CDM by taking a repetitive sequence suitable for their transmission bandwidths . In this case, since the base station receives circular shifted CAZAC sequence of 5 MHz, it can multiplex reference signals or pilots of user equipments having different transmission bandwidths.
The aforementioned example has been described based on that a plurality of user equipments perform multiplexing by using CAZAC sequences having different bandwidth lengths. However, even in case that the user equipments perform multiplexing by using CAZAC sequences having different time lengths, uplink signals of the user equipments can be identified with maintaining orthogonality by setting a CAZAC sequence having a length corresponding to a common measure of the different time lengths as a basic sequence and allowing each user equipment to repeatedly use the CAZAC sequence in accordance with a time length of a sequence used for CDM. Furthermore, the repetitive scheme of the CAZAC sequence can be implemented by direct repetitive insertion in a time domain/frequency domain. Alternatively, it will be apparent to those skilled in the art that the CAZAC sequence can be generated as a repetitive sequence by a predetermined processing procedure in domains different from the repetitive time domain/frequency domain.
Hereinafter, a method for transmitting uplink signals from user equipments to perform signal multiplexing of user equipments having different frequency bands by using the aforementioned CDM scheme will be described.
FIG. 6 is a flow chart illustrating a method for transmitting uplink signals from user equipments in accordance with the preferred embodiment of the present invention.
In the method for transmitting uplink signals in accordance with the preferred embodiment of the present invention as shown in FIG. 6, the user equipment selects basic sequences to be used for its uplink signal multiplexing in step S601. The basic sequences are selected from different original sequences such as CAZAC sequences having different IDs, orthogonal sequences having mutual orthogonality by applying different circular shifts to the same original sequence, and a group consisting of combination of the original sequences and the orthogonal sequences, and represent sequences having the basic bandwidth described with reference to FIG. 4 and FIG. 5.
If the multiplexing method described with reference to
FIG. 4 and FIG. 5 is defined in a specific communication system, the corresponding communication system can previously set the aforementioned basic frequency band and the basic sequences considering bandwidths of the user equipments. In this case, each user equipment can select a sequence for its multiplexing among the basic sequences previously set in the communication system when transmitting uplink signals.
Afterwards, the user equipment checks whether its frequency bandwidth is wider than the aforementioned basic frequency band in step S602. If the frequency bandwidth of the user equipment is wider than the basic frequency band, the current step advances to step S603 so that the user equipment repeats the basic sequence selected in step S601 to have its bandwidth length and configures the repeated sequence as CDM signal in step S604. This CDM signal could be a repetitive sequence, for example, a repetitive type CAZAC sequence if a transmitting signal is a pilot signal. Also, if a transmitting signal is specific data, the CDM signal could be a type obtained by multiplying the repetitive type CAZAC sequence by the corresponding data. Afterwards, the CDM signal generated as above is transmitted through step S606.
Meanwhile, if the bandwidth used by the user equipment is not wider than the basic bandwidth, the current step advances to step S605. In this case, the user equipment generates a CDM signal by using the basic sequence in the transmitting signal as it is, and transmits the generated CDM signal to an uplink through step S606. The generated CDM signal could be the basic sequence if the transmitting signal is a pilot. Alternatively, if the transmitting signal is specific data, the generated CDM signal could be a type obtained by multiplying the basic sequence by the data.
In case of the CDM signal generated as above, even if the sequence used in the transmitting signal has a length different from that of the sequence used in another user equipment, orthogonality is maintained when the CDM signal is detected through a sequence corresponding to the basic frequency band length, whereby the base station can identify whether the transmitting signal has been transmitted from which user equipment.
It will be apparent to those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit and essential characteristics of the invention. Thus, the above embodiments are to be considered in all respects as illustrative and not restrictive. The scope of the invention should be determined by reasonable interpretation of the appended claims and all change which comes within the equivalent scope of the invention are included in the scope of the invention.
INDUSTRIAL APPLICABILITY
According to the preferred embodiment of the present invention, a plurality of user equipments set a bandwidth corresponding to a common measure of different transmission bandwidths as a basic bandwidth, and select basic sequences applied to the basic bandwidth to repeatedly use the basic sequences to be equivalent to a bandwidth of a corresponding user equipment, thereby maintaining orthogonality even in case that sequences used for multiplexing are different from one another in their length. As a result, the base station can easily identify whether received uplink signals have been transmitted from which user equipment, while maintaining a CDM scheme as a multiplexing scheme.
In addition, the user equipment can implement multiplexing of the CDM scheme according to the present invention by transmitting signals in accordance with the aforementioned method for transmitting uplink signals.
The aforementioned method according to the present invention can be applied to a random communication system as well as 3GPP LTE system.

Claims

WHAT IS CLAIMED IS:
1. A multiplexing method comprising: setting a bandwidth corresponding to a common measure of bandwidths which a plurality of user equipments respectively use, as a basic bandwidth; selecting basic sequences corresponding to the basic bandwidth to perform signal multiplexing of the plurality of user equipments; and performing multiplexing using a sequence obtained by repeating the basic sequences in case of a signal of a specific user equipment, which uses a bandwidth more than the basic bandwidth, among the plurality of user equipments.
2. The multiplexing method of claim 1, wherein the number of repetition times of the basic sequences in the multiplexing corresponds to a number obtained by dividing the bandwidth of the specific user equipment, which uses a bandwidth more than the basic bandwidth, by the basic bandwidth.
3. The multiplexing method of claim 1, wherein the basic sequences selected in the selecting of the basic sequences corresponding to the basic bandwidth are original sequences different from each other, orthogonal sequences having mutual orthogonality, obtained by applying different circular shifts to the same original sequence, and sequences selected from a group consisting of combination of the original sequences and the orthogonal sequences.
4. A method for transmitting uplink signals from a user equipment, the method comprising: selecting a predetermined sequence as a transmitting signal; and transmitting the selected predetermined sequence through an uplink, wherein the predetermined sequence is a sequence obtained by repeating basic sequences if a bandwidth which the user equipment uses is wider than that of the basic sequences.
5. The method of claim 4, wherein the basic sequences are sequences having a bandwidth corresponding to a common measure of bandwidths of a plurality of user equipments which are served by the same base station as that of the user equipment .
6. The method of claim 5, wherein the basic sequences
■ are original sequences different from each other, orthogonal sequences having mutual orthogonality, obtained by applying different circular shifts to the same original sequence, and sequences selected from a group consisting of combination of the original sequences and the orthogonal sequences.
7. A method for identifying signals, the method comprising: receiving uplink signals; and checking whether the received signals have been transmitted from which user equipment through a predetermined sequence used in the received signals, wherein the predetermined sequence is a basic sequence having a basic bandwidth corresponding to a common measure of bandwidths of a plurality of user equipments which are provided with services by a base station.
PCT/KR2007/004675 2006-09-22 2007-09-21 Method for multiplexing user equipment signals having different bandwidth, and method for transmitting uplink signal WO2008035955A2 (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008038114A3 (en) * 2006-09-26 2008-08-07 Nokia Corp Apparatus, method and computer program product providing sequence modulation for uplink control signaling
US8036197B2 (en) 2006-10-03 2011-10-11 Nokia Corporation Signalling
US8144570B2 (en) 2006-09-26 2012-03-27 Nokia Corporation Apparatus, method and computer program product providing multiplexing for data-non-associated control channel
WO2018228208A1 (en) * 2017-06-16 2018-12-20 华为技术有限公司 Communication method, base station and terminal device

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020159470A1 (en) * 2000-02-02 2002-10-31 Hiroyuki Atarashi Single-carrier/ds-cdma packet transmitting method, uplink packet transmitting method in multi carrier/ds-cdma mobile communication system, and structure of downlink channel in multi carrier/ds-cdma mobile comunication system
WO2005114928A1 (en) * 2004-05-11 2005-12-01 Sbc Knowledge Ventures, L.P. Digital subscriber line user capacity estimation
US20060187942A1 (en) * 2005-02-22 2006-08-24 Hitachi Communication Technologies, Ltd. Packet forwarding apparatus and communication bandwidth control method

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1032154A2 (en) 1999-02-23 2000-08-30 TRW Inc. Configurable multi-rate channelizer for use in multiple data rate applications
US6393066B1 (en) 1999-02-26 2002-05-21 Trw Inc. Efficient digital channelizer system and method of operation thereof

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020159470A1 (en) * 2000-02-02 2002-10-31 Hiroyuki Atarashi Single-carrier/ds-cdma packet transmitting method, uplink packet transmitting method in multi carrier/ds-cdma mobile communication system, and structure of downlink channel in multi carrier/ds-cdma mobile comunication system
WO2005114928A1 (en) * 2004-05-11 2005-12-01 Sbc Knowledge Ventures, L.P. Digital subscriber line user capacity estimation
US20060187942A1 (en) * 2005-02-22 2006-08-24 Hitachi Communication Technologies, Ltd. Packet forwarding apparatus and communication bandwidth control method

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008038114A3 (en) * 2006-09-26 2008-08-07 Nokia Corp Apparatus, method and computer program product providing sequence modulation for uplink control signaling
US8144570B2 (en) 2006-09-26 2012-03-27 Nokia Corporation Apparatus, method and computer program product providing multiplexing for data-non-associated control channel
US8036197B2 (en) 2006-10-03 2011-10-11 Nokia Corporation Signalling
US8576823B2 (en) 2006-10-03 2013-11-05 Nokia Corporation Generating pilot sequence for reference signal
WO2018228208A1 (en) * 2017-06-16 2018-12-20 华为技术有限公司 Communication method, base station and terminal device

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