WO2007003133A1 - Méthode de multiplexage de fréquence orthogonale, de modulation et dispositif d’accès dans système ofdm - Google Patents

Méthode de multiplexage de fréquence orthogonale, de modulation et dispositif d’accès dans système ofdm Download PDF

Info

Publication number
WO2007003133A1
WO2007003133A1 PCT/CN2006/001546 CN2006001546W WO2007003133A1 WO 2007003133 A1 WO2007003133 A1 WO 2007003133A1 CN 2006001546 W CN2006001546 W CN 2006001546W WO 2007003133 A1 WO2007003133 A1 WO 2007003133A1
Authority
WO
WIPO (PCT)
Prior art keywords
sub
parallel
power
subcarrier
power coefficient
Prior art date
Application number
PCT/CN2006/001546
Other languages
English (en)
French (fr)
Inventor
Xuezhi Yang
Original Assignee
Huawei Technologies Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Huawei Technologies Co., Ltd. filed Critical Huawei Technologies Co., Ltd.
Publication of WO2007003133A1 publication Critical patent/WO2007003133A1/zh

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2626—Arrangements specific to the transmitter only
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/04—TPC
    • H04W52/30—TPC using constraints in the total amount of available transmission power
    • H04W52/34—TPC management, i.e. sharing limited amount of power among users or channels or data types, e.g. cell loading

Definitions

  • the present invention relates to wireless communication technologies, and more particularly, to a frequency multiplexing, modulation method, and access device for implementing an Orthogonal Frequency Division Multiplexing (OFDM) system.
  • OFDM Orthogonal Frequency Division Multiplexing
  • Orthogonal Frequency Division Multiplexing is an orthogonal frequency multiplex transmission multiplexing transmission technology.
  • OFDM transmission technology is an efficient data transmission method.
  • the basic implementation method is to divide a given channel into multiple orthogonal subchannels in the frequency domain, use one subcarrier for modulation on each subchannel, and transmit each subcarrier in parallel. .
  • each subchannel is relatively flat, and narrowband transmission is performed on each subchannel, and the signal bandwidth is smaller than the channel bandwidth, thereby greatly eliminating signal waveforms. Interference.
  • the OFDM transmission technique differs in that the sub-carrier spectrum is partially overlapped, and the data signals can be separated from the overlapping sub-carriers as long as the sub-carriers are orthogonal to each other. Since the OFDM transmission technology allows the subcarrier spectrum to overlap, its spectral efficiency can be greatly improved, and thus the OFDM transmission technique is an efficient modulation method.
  • OFDM transmission technology was first proposed in the mid-1960s, but for a long time thereafter, OFDM technology has not formed a large-scale application. At that time, the development of OFDM transmission technology encountered many problems that were difficult to solve.
  • OFDM transmission technology requires that each subcarrier be orthogonal to each other, although 'theoretically, the modulation method can be well realized by Fast Fourier Transform (FFT).
  • FFT Fast Fourier Transform
  • such a complicated real-time Fourier transform device cannot be realized at all according to the technical means provided at the time.
  • the stability of the transmitter oscillator and receiver oscillator and the linearity requirements of the RF power amplifier It has also become a constraint for implementing OFDM transmission technology.
  • FIG. 1 is a schematic diagram showing a user data transmission process in the prior OFDM technology.
  • user data is first subjected to channel coding and interleaving processing, and some modulation methods, such as a two-phase phase shift keying signal (BPSK), are employed.
  • BPSK phase shift keying signal
  • Modulation, four-phase phase shift keying (QPSK) modulation, quadrature amplitude modulation (QAM), etc. form data cells, which are then modulated onto the radio frequency by OFDM operation.
  • QPSK quadrature amplitude modulation
  • the data cells to be transmitted are first serial/parallel converted to form n low-speed parallel sub-data streams, each sub-data stream occupies one sub-carrier; sub-stream to sub-carrier mapping (ie, The frequency domain signal is converted to the time domain) can be realized by inverse Fourier transform, such as inverse discrete Fourier transform (IDFT) or inverse fast Fourier transform (IFFT); while OFDM technology uses cyclic prefix (CP) as the guard interval, greatly reducing even Inter-symbol interference is eliminated, and orthogonality between channels is ensured, thereby greatly reducing mutual interference between channels.
  • inverse Fourier transform such as inverse discrete Fourier transform (IDFT) or inverse fast Fourier transform (IFFT)
  • CP cyclic prefix
  • the fast frequency hopping OFDM radio transmission technology divides the spectrum resources into time-frequency grids, and each physical channel corresponds to a time-frequency grid pattern.
  • time-frequency grids corresponding to different physical channels are orthogonal to each other to avoid mutual interference between physical channels in a cell.
  • a physical channel occupies different frequencies at different times, and frequency selective fading can be overcome.
  • the current OFDM basic time-frequency pattern is generated.
  • the time-frequency pattern is generated according to the COSTA sequence of length 15.
  • the time-frequency patterns of other different cells are from the basic time-frequency pattern at the frequency.
  • the domain is obtained by cyclic shifting.
  • Fast frequency hopping OFDM transmission technology averages neighbors by designing time-frequency patterns Mutual interference of small intervals, but in the case of co-frequency networking (that is, different cells adopt the same frequency resources), when the load of the cell increases, the same-frequency interference of one physical channel by the adjacent cell also increases. All frequency resources are used in one cell, and adjacent cells of the cell will be interfered regardless of frequency hopping. If the interfered terminal is closer to the antenna of the cell in which it is located, the terminal still has a relatively high signal-to-noise ratio, and still can achieve a relatively small error probability; if the interfered terminal is located at the edge of the cell where it is located, the distance is The difference is that the terminal will have a higher probability of error.
  • the main object of the present invention is to provide an OFDM frequency multiplexing method for reducing mutual interference between adjacent cells and improving resource utilization of the wireless communication system.
  • the present invention also provides an OFDM modulation method and an OFDM access device for implementing controllable adjustment of each subcarrier of OFDM.
  • each cell base station adopts an OFDM system, and the neighboring cells use the same spectrum resource, and in the process of transmitting data in each cell base station, when performing OFDM operation, The following steps:
  • the power coefficients of the sub-streams are The respective power coefficient thresholds, and the power coefficient threshold of at least one sub-stream is different from the power coefficient threshold of the other data streams; wherein the inverse Fourier transform may preferably be IFFT or IDFT;
  • the sub-transformed subcarriers are converted into one output in parallel.
  • the subcarriers mapped by the substreams with high power coefficient thresholds of different neighboring cells do not overlap each other.
  • the power coefficient threshold of each channel changes according to a change of time.
  • the method further includes: when the cellular network is used, the sum of the number of sub-data streams corresponding to the power coefficient threshold corresponding to the three cells in the two adjacent cells, and the multi-path The total number of data streams is the same.
  • the method further includes: performing interleaving operation on each sub-stream.
  • the method before converting the Fourier inversely transformed subcarriers into one channel, the method further comprises: adding a cyclic prefix to each subcarrier.
  • the orthogonal frequency division multiplexing modulation method provided by the present invention comprises the following steps:
  • the sub-transformed subcarriers are converted into one output in parallel.
  • the Orthogonal Frequency Division Multiple Access (OFDM) access device includes:
  • a parallel-to-parallel converter for converting the input data string into a multi-parallel sub-stream output
  • a Fourier inverse transform converter configured to receive the multi-path data stream and perform Fourier inverse mapping on the corresponding multi-path subcarrier
  • the parallel-serial converter is configured to receive the multi-channel subcarrier outputted by the inverse Fourier transform, and convert the serial to one output;
  • a subcarrier power coefficient adjuster for multiplying the parallel parallel sub-data streams output by the serial-to-parallel converter by each of the parallel sub-data streams for the opposite Power factor of power adjustment of the mapped subcarriers
  • the subcarrier power threshold control logic is configured to control a threshold of a power coefficient multiplied by each of the substreams.
  • the method further includes: an interleaving aligner for interleaving the data streams to be received by the inverse Fourier transform converter.
  • the method further includes: adding a cyclic prefix unit, configured to add each subcarrier to be converted by the parallel/serial converter to the cyclic prefix.
  • a transmitter comprising the orthogonal frequency division multiplexing access device of any of the preceding claims.
  • the present invention can adjust the transmit power on different subcarriers by multiplying a coefficient on the subcarrier, and each subcarrier performs different power gate control.
  • the subcarrier group with high power threshold is used as the primary subcarrier of the cell, and is applied to the data transmission at the cell edge and the cell.
  • the subcarrier group with a power threshold of 4 ⁇ is used as the subcarrier carrier and is only applied to the data transmission inside the cell.
  • the subcarrier groups in which the primary subcarriers of the neighboring cells are located do not overlap each other, and the co-channel interference between the primary subcarriers does not occur, thereby reducing mutual interference between adjacent cells, and the transmit power of the secondary subcarriers is relatively low, The interference to neighboring cells is reduced. Therefore, the communication quality can be improved, and single frequency networking can be realized, and the spectrum utilization efficiency is improved.
  • Figure 1 shows a schematic diagram of an existing OFDM transmission process
  • Figure 2 shows a schematic diagram of the current OFDM basic time-frequency pattern.
  • FIG. 3 is a schematic diagram showing the networking interference formed by the existing OFDM frequency packet division
  • FIG. 4 is a schematic diagram showing an exemplary networking of the frequency multiplexing manner of the OFDM implementation of the present invention
  • FIG. 5 is a diagram showing the formation of the OFDM frequency packet division according to the present invention. Exemplary networking diagram
  • FIG. 6 shows an exemplary schematic diagram of an OFDM transmission process of the present invention. Mode for carrying out the invention
  • the analysis of the interference of the prior art cell is performed. As shown in FIG. 3, the networking formed by the existing OFDM frequency packet division is shown.
  • the transmission power thresholds of the subcarriers in the OFDM system are the same, and thus, due to the subcarriers.
  • the coverage is the same, so in the edge regions of adjacent cells, relatively strong interference occurs between subcarriers of the same frequency.
  • all subcarriers of the OFDM system are divided into N groups, and different neighboring cells select different groups of subcarriers as the primary subcarriers of the current cell, and other subcarriers serve as the secondary subcarriers of the local cell,
  • the primary subcarrier and the secondary subcarrier of the cell are set with different transmit power thresholds, and the transmit power threshold of the primary subcarrier is higher than the transmit power threshold of the secondary subcarrier, and the cell boundary is determined by the coverage of the primary subcarrier.
  • the low-power sub-subcarrier is mainly used to transmit data.
  • the terminal can receive the clear signal of the local cell, and because the sub-subcarrier power is small, the interference to the neighboring cell is relatively small;
  • the high-power primary carrier is used to transmit data, and the terminal in the edge area mainly receives the primary sub-carriers of different neighboring cells, because the primary sub-carriers of different neighboring cells do not overlap and are not at the same frequency. , in the orthogonal, so mutual interference will be greatly reduced.
  • the base station 1 is in charge of the terminal 11 and the terminal 12, and the terminal 12 is located inside the jurisdiction of the base station 1, such as a cell radius centered on the base station 1.
  • the terminal 11 is located at the boundary of the base station 1 jurisdiction, such as at 90% of the cell radius centered on the base station 1;
  • the base station 2 governs the terminal 21 and the terminal 22, and the terminal 21 is located in the jurisdiction of the base station 2.
  • the terminal 22 is located inside the jurisdiction of the base station 2; the base station 3 governs the terminal 31 and the terminal 32, the terminal 31 is located at the boundary of the jurisdiction of the base station 3, and the terminal 32 is located inside the jurisdiction of the base station 3.
  • the gray indicates the primary subcarrier, and the power is large; the diagonal line indicates the secondary subcarrier, the transmission power is small, and the primary subcarriers used by different base stations are different.
  • the terminal 11 located at the cell boundary receives the primary subcarrier of the base station 1, although the primary subcarrier of the base station 2 and the base station 3 is received, the primary subcarriers of the received different base stations are not at the same frequency and are orthogonal to each other. Therefore, co-channel interference can be avoided.
  • the terminal 12 located inside the cell of the base station since each base station limits the transmission power, it is not interfered by the signal of the adjacent base station, or the interference is small.
  • the subcarrier grouping and the division of the primary subcarrier and the secondary subcarrier may be fixed, or may be dynamically changed according to time, that is, the subcarrier grouping and the division of the primary subcarrier and the secondary subcarrier may be arbitrarily changed, as long as the guarantee is ensured.
  • the neighboring cells do not use the same subcarrier at the same time. For example, there are 6 subcarriers, and the corresponding identifiers are 1, 2, 3, 4, 5, and 6, respectively.
  • the subcarriers identified as 1 and 2 are divided into a group of subcarriers, which will be identified as 3 and
  • the subcarriers of 5 are divided into a group of subcarriers
  • the subcarriers identified as 4 are divided into a group of subcarriers
  • the subcarriers identified as 6 are divided into a group of subcarriers
  • the cell 1 is identified by the group of 1 and 2.
  • the subcarrier is used as the primary subcarrier of the local cell, and the remaining subcarriers are used as the secondary subcarriers of the local cell.
  • the neighboring cell 2 uses the subcarriers identified by 4 as the primary subcarrier of the local cell, and the remaining subcarriers serve as the secondary subcarriers of the local cell.
  • the 5 subcarriers can be regrouped, the subcarriers identified as 2 and 5 are divided into a group of subcarriers, and the subcarriers identified as 4 and 6 are divided into a group of subcarriers, which will be identified as 1
  • the subcarriers are divided into a group of subcarriers, and the subcarriers identified as 3 are divided into a group of subcarriers, and the group 1 is identified as the primary subcarrier of the current cell, and the remaining subcarriers are used as the primary carrier.
  • Secondary subcarrier The neighboring cell 2 uses the group of subcarriers identified by 3 as the primary subcarrier of the current cell, and the remaining subcarriers serve as the secondary subcarriers of the local cell.
  • an exemplary networking diagram formed by OFDM frequency packet division as shown in FIG. 5 the typical value of the packet may be 3, and the network shape at this time
  • the formula is also a cellular network (each three cells are adjacent to each other). This form of cellular network can maximize system capacity and maximize spectrum efficiency. It is not difficult to understand that to achieve the highest spectral efficiency, the subcarriers are divided into three groups, and different subcarrier groups are used by adjacent cells.
  • N can also take other values, such as 4, 5, 6, 7, 8, and so on.
  • Orthogonal Frequency Division Multiplexing (OFDM) modulation method of the present invention is implemented to implement a method for controlling each subcarrier power and, in turn, implementing the frequency reuse of the OFDM system of the present invention.
  • OFDM Orthogonal Frequency Division Multiplexing
  • the OFDM modulation process includes the following steps: Step 1: When the modulated user data cell performs OFDM operation, first performing serial-to-parallel conversion to convert the input serial data cell into n-channel. Parallel sub-data stream, let n parallel sub-data streams be f ( 1 ) , f ( 2 ) . . . f ( n ).
  • Step 3 Each sub-stream of each group is multiplied by a power coefficient for adjusting the transmit power of each subcarrier to be mapped, which can be implemented by a subcarrier power coefficient adjuster. Different power factor thresholds can be used for different groups.
  • each of the power coefficients is controlled with a respective power coefficient threshold, which can be implemented by a subcarrier power threshold control logic.
  • the threshold of the power coefficient multiplied by the sub-data stream of the control group may be higher than the power coefficient threshold of the other group sub-stream, for example, the power coefficient threshold is divided into two parts, a part of the power coefficient threshold is G1, and the other part is G2, and G1>G2.
  • the subcarrier group corresponding to G1 may be used as the primary subcarrier of the current cell, and the subcarrier group corresponding to G2 may be used as the secondary subcarrier.
  • the cell 1 adopts the sub-carrier g ( 1 ) group power threshold is G1
  • the power threshold of the other subcarrier groups is G2
  • the neighboring cell 2 adopts the g (2) group power threshold is G1
  • the other subcarrier group power threshold is G2
  • the neighboring cell 3 adopts the g (3) group power threshold is G1
  • the other subcarrier group power threshold is G2, and the OFDM frequency multiplexing shown in FIG. 4 can be realized.
  • the IF usage rate is the highest, and the subcarriers need to be divided into three groups, and the three adjacent cells are different.
  • the sum of the number of sub-data streams with high power coefficient thresholds corresponding to the three cells is the same as the total number of sub-streams.
  • Step 4 The n-way parallel data streams are interleaved and arranged according to a certain manner, and the manner of interleaving determines the mapping manner of the sub-carriers.
  • Step 5 The interleaved parallel data stream is inversely Fourier transformed (which may be IFFT/IDFT) and mapped to n subcarriers corresponding to n data.
  • IFFT/IDFT inversely Fourier transformed
  • Step 6 Each subcarrier is added with a cyclic prefix CP, which is used to overcome crosstalk between symbols, and then parallel-transformed into one way to complete the OFDM operation.
  • CP cyclic prefix
  • step 4 The interleaving arrangement corresponding to step 4 and the cyclic prefix of step 6 are optional steps. In addition, the interleaving arrangement described in step 4 may also be after step 1.
  • a corresponding device including: a serial-to-parallel converter for converting the input data string into multiple parallel data outputs; subcarrier power a coefficient adjuster for multiplying the parallel data streams output by the serial-to-parallel converter by a power coefficient for each parallel data stream before being received by the inverse Fourier transform, the power coefficient being used for mapping each data stream
  • the subcarrier power threshold control logic is configured to control the threshold of each subcarrier power coefficient, specifically, the subcarrier power threshold control logic is the power multiplied by each subcarrier.
  • the coefficients provide a threshold, respectively, and the limiting power factor can only be changed within its threshold.
  • the inverse Fourier transform is configured to receive the multi-channel data stream and perform inverse Fourier transform to map to corresponding multi-channel subcarriers
  • the parallel-serial converter is configured to receive the multi-channel subcarrier outputted by the inverse Fourier transform, and serially convert the signal into one output.
  • an interleaving/arranging unit for interleaving the data streams to be received by the inverse Fourier transform converter, and a cyclic prefix for adding each subcarrier to be converted by the parallel-serial converter to the cyclic prefix may be further included. unit.
  • the orthogonal frequency division multiplexing access device proposed by the present invention can be applied to a transmitter.
  • the manner in which the Orthogonal Frequency Division Multiple Access (OFDM) access device is incorporated into the transmitter is clear to those skilled in the art, and thus will not be described in detail.
  • OFDM Orthogonal Frequency Division Multiple Access
  • these channels can be set to use only the primary subcarrier of the current cell, and a higher transmit power and a coverage area of the adjacent cell are used. Although there are overlaps, the mutual interference is relatively low, which is beneficial to the cell selection, handover and correct reception of common control information.
  • only primary subcarrier bearer signaling may be used.
  • the service channel uses only the primary subcarrier. Since the primary subcarriers of the neighboring cells do not overlap each other, the mutual interference between the neighboring cells can be reduced, and the communication quality is improved.
  • the cell edge area may be pre-defined, such as 75% of the coverage of the base station as the edge area of the cell.
  • the terminal can be set closer to the base station, and the primary subcarrier and the secondary subcarrier are simultaneously used to realize high-speed data and multimedia service transmission. Since the transmission power of the secondary subcarrier is relatively low, interference to neighboring cells is reduced, and the utilization efficiency of the spectrum is improved.
  • the distance may be a set range, such as within 75% of the coverage area of the cell. If the distance between the terminal and the base station is within the set range, the terminal may be regarded as being closer to the base station.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Description

实现正交频分复用系统的频率复用、 调制方法及接入设备 技术领域
本发明涉及无线通信技术， 更具体地说， 特别是指实现正交频分复 用 （OFDM ) 系统的频率复用、 调制方法及接入设备。 发明背景
正交频分复用 ( OFDM, Orthogonal Frequency Division Multiplexing ) 是正交频率多路传输分割复用传输技术。 OFDM传输技术是一种高效的 数据传输方式， 其基本实现方式是在频域内将给定信道分成多个正交子 信道， 在每个子信道上使用一个子载波进行调制， 并且各子载波并行传 输。 这样， 虽然总的信道是非平坦的， 具有频率选择性， 但是每个子信 道都是相对平坦的， 在每个子信道上进行的是窄带传输， 信号带宽小于 信道带宽， 因此， 可以大大消除信号波形间的干扰。 与一般多载波传输 技术相比， OFDM传输技术的不同之处在于允许子载波频谱部分重叠， 只要满足子载波间相互正交， 就能够将数据信号从重叠的子载波上分离 出来。 由于 OFDM传输技术允许子载波频谱重叠， 因此其频谱效率可大 大提高 , 因而 OFDM传输技术是一种高效的调制方式。
OFDM传输技术在二十世纪六十年代中期被首次提出， 但在此后相 当长的一段时间， OFDM技术一直没有形成大规模的应用。 当时 OFDM 传输技术的发展遇到了很多难于解决的问题， 首先， OFDM传输技术要 求各个子载波之间相互正交， 尽管'理论上通过快速傅立叶变换（FFT ) 可很好地实现这种调制方式， 但在实际应用中， 根据当时提供的技术手 段， 如此复杂的实时傅立叶变换设备是根本无法实现的。 此外， 发射机 振荡器和接收机振荡器的稳定性以及射频功率放大器的线性要求等因 素也成为实现 OFDM传输技术的制约条件。二十世纪八十年代以来， 大 规模集成电路技术的发展解决了 FFT 的实现问题， 随着数字信号处理 ( DSP )技术的发展,格栅编码（ Trellis Code )技术、软判决（ Soft Decision ) 技术、 信道自适应技术等的应用， OFDM传输技术开始从理论向实际应 用转化。
图 1示出了现有 OFDM技术中用户数据传输过程示意图，如图 1所 示， 用户数据首先经过信道编码和交织处理， 并采用一些调制方法、 如 二相制相移键控信号（BPSK )调制、 四相制相移键控信号 （QPSK )调 制、 正交幅度调制 （QAM )等形成数据信元， 然后经过 OFDM操作调 制到射频上。 在 OFDM操作中， 首先将待发送的数据信元进行串行 /并 行转换， 形成 n路低速并行的子数据流， 每个子数据流将占用一个子载 波； 子数据流到子载波的映射（即将频域信号转换到时域）可通过傅立 叶反变换实现， 如可以是离散傅立叶反变换（IDFT )或快速傅立叶反变 换（IFFT ); 同时 OFDM技术使用循环前缀（CP )作为保护间隔， 大大 减少甚至消除了码间干扰， 并且保证了各信道之间的正交性， 从而大大 减少了信道间的相互干扰。
快跳频的 OFDM无线传输技术将频谱资源划分成时间一频率栅格， 每一条物理信道对应一个时间一频率栅格的图样。 在一个小区内， 不同 物理信道对应的时间一频率栅格是相互正交的， 以此来避免一个小区内 物理信道间的相互干扰。 而且， 一个物理信道在不同时间占据不同的频 率，可以克服频率选择性衰落。如图 2所示现有 OFDM基本时间一频率 图样示意图，该时间一频率图样是根据长度为 15的 COSTA序列产生的， 其他不同小区的时间一频率图样都是从这个基本时间一频率图样在频 率域通过循环移位得到的。
快跳频的 OFDM传输技术通过时间一频率图样的设计来平均相邻 小区间的相互干扰， 但是， 在同频組网 （即不同小区采用相同的频普资 源） 的情况下， 当小区的负荷增加时， 一条物理信道受到相邻小区的同 频干扰也会增加。 在一个小区使用了所有的频率资源， 该小区的相邻小 区无论如何跳频都会受到干扰。 如果受到干扰的终端与其所在小区的天 线距离比较近， 则该终端仍然具有比较高的信噪比， 仍然能够达到比较 小的错误概率； 如果受到干扰的终端位于其所在小区的边缘， 则由于距 离的差别该终端将会出现比较高的错误概率。 发明内容
有鉴于此， 本发明的主要目的在于提供了一种 OFDM频率复用的方 法， 以降低相邻小区间的相互干扰, 提高无线通信系统的资源利用率。
本发明还提供了一种 OFDM调制方法及 OFDM接入设备， 以实现 OFDM各个子载波的功能可控制下的调整。
本发明提供的实现正交频分复用系统频率复用的方法， 各个小区基 站采用 OFDM系统， 相邻小区采用相同的频谱资源， 在各个小区基站发 送数据过程中， 在进行 OFDM操作时， 包括以下步骤：
将输入的串行数据流转换为多路并行子数据流；
将各路子数据流与用于对所映射的子载波进行功率调整的功率系 数的乘积作傅立叶反变换映射到所述各路子数据流对应的子载波上； 所 述各路子数据流的功率系数有各自的功率系数门限， 且至少一路子数据 流的功率系数门限与其他路数据流的功率系数门限不同； 其中傅立叶反 变换优选可以是 IFFT或 IDFT;
将傅立叶反变换后的各路子载波并串转换为一路输出。
其中， 不同相邻小区对应功率系数门限高的子数据流映射的子载波 互不重叠。 其中， 所述各路功率系数门限根据时间的变化进行变化。
其中， 进一步包括： 当采用蜂窝网方式组网时， 两两相邻的三个小 区中， 所述三个小区分别对应的功率系数门限高的子数据流路数之和， 与所述多路子数据流总路数相同。
其中， 在将输入的串行数据流转换为多路并行子数据流后， 或将各 路子数据流作傅立叶反变换前， 进一步包括： 对各路子数据流进行交织 排列操作。
其中， 将傅立叶反变换后的各路子载波并串转换为一路之前， 进一 步包括： 各路子载波加循环前缀。
本发明提供的正交频分复用调制方法， 包括以下步骤：
将输入的串行数据流转换为多路并行子数据流；
将各路子数据流与用于对所映射的子载波进行功率调整的功率系 数的乘积作傅立叶反变换映射到所述各路子数据流对应的子载波上， 其 中所述各路子数据流的功率系数有各自的功率系数门限， 且至少一路子 数据流的功率系数门限与其他路数据流的功率系数门限不同；
将傅立叶反变换后的各路子载波并串转换为一路输出。
本发明提供的正交频分复用接入设备， 包括：
串并变换器， 用于将输入的数据串并转换为多路并行子数据流输 出；
傅立叶反变换变换器， 用于接收所述多路数据流进行傅立叶反映射 到对应的多路子载波上；
并串变换器， 用于接收傅立叶反变换变换器输出的多路子载波， 并 串变换为一路输出； 还包括：
子载波功率系数调节器， 用于将串并变换器输出的多路并行子数据 流在由傅立叶反变换接收之前， 对各路并行子数据流分别乘上用于对所 映射的子载波进行功率调整的功率系数；
子载波功率门限控制逻辑器， 用于对所述各路子数据流所乘的功率 系数的门限进行控制。
其中， 进一步包括： 交织排列器， 用于将傅立叶反变换变换器要接 收的数据流进行交织排列。
其中， 进一步包括： 加循环前缀单元， 用于将并串变换器要转换的 每一路子载波加入循环前缀。
一种发射机， 该发射机包括如上任一项所述的正交频分复用接入设 备。
由上述方法可以看出， 本发明通过在子载波上乘上一个系数， 可以 调整不同子载波上的发射功率， 并且各路子载波进行不同的功率门 P艮控 制。 功率门限高的子载波组作为本小区的主子载波， 应用于小区边缘和 小区内部的数据传输； 功率门限 4氐小的子载波组作为附子载波， 只应用 于小区内部的数据传输。 其中， 相邻小区的主子载波所在子载波組互不 重叠， 不会出现主子载波间的同频干扰， 从而降低了相邻小区间的相互 干扰， 而副子载波的发射功率相对较低， 也降低了对相邻小区的干扰。 所以能够提高通信质量， 并且可以实现单频组网， 提高了频谱的利用效 率。 附图简要说明
图 1示出了现有 OFDM传输过程示意图；
.图 2示出了现有 OFDM基本时间一频率图样示意图
图 3示出了现有 OFDM频率分组划分形成的组网干扰示意图； 图 4示出了本发明 OFDM实现的频率复用方式示范性组网示意图； 图 5示出了本发明 OFDM频率分组划分形成的示范性组网图； 图 6示出了本发明 OFDM传输过程示范性示意图。 实施本发明的方式
首先针对现有技术小区干扰的情况进行分析， 如图 3 示出现有 OFDM频率分组划分形成的组网， 现有技术中 OFDM系统中各子载波 的发射功率门限相同， 这样， 由于各子载波的覆盖范围相同， 因此在各 相邻小区的边缘区域， 处于同频的子载波之间就会产生比较强的干扰。
有鉴于此， 本发明中， 将 OFDM系统所有子载波划分成 N组， 不 同的相邻小区选择不同组的子载波作为本小区的主子载波， 其他子载波 作为本小区的副子载波， 对各小区的主子载波和副子载波设置不同的发 射功率门限， 且主子载波的发射功率门限高于副子载波的发射功率门 限， 以主子载波的覆盖范围确定小区边界。 这样， 对于小区内部， 主要 采用低功率副子载波传输数据， 由于离基站比较近， 终端可以接收到本 小区清晰的信号，并且由于副子载波功率小，对相邻小区的干扰比较小； 而在各相邻小区边缘区域， 采用高功率主载波传输数据， 处于边缘区域 的终端主要接收到的是不同相邻小区的主子载波， 由于不同相邻小区的 主子载波不相重叠不处于同频上， 处于正交， 因此相互干扰就会大大降 低。
具体可以参见图 4 示出的本发明中频率复用方式示范性组网示意 图，基站 1管辖终端 11和终端 12,终端 12位于基站 1管辖区域的内部， 如位于以基站 1为中心的小区半径的 30%处， 终端 11位于基站 1管辖 区域的边界， 如位于以基站 1为中心的小区半径的 90%处； 同样的， 基 站 2管辖终端 21和终端 22， 终端 21位于基站 2管辖区域的边界， 终端 22位于基站 2管辖区域的内部； 基站 3管辖终端 31和终端 32, 终端 31 位于基站 3管辖区域的边界， 终端 32位于基站 3管辖区域的内部。 以 基站 1来说， 发射的子载波中， 灰色表示的是主子载波， 其功率较大； 斜划线表示的是副子载波， 发射功率较小， 并且不同的基站采用的主子 载波不同。 这样， 位于小区边界的终端 11接收基站 1的主子载波时， 虽然会收到基站 2、 基站 3的主子载波的干扰， 但由于接收的不同基站 的主子载波并不在同频上且互为正交， 因此可避免同频干扰。 位于基站 1的小区内部的终端 12来说， 由于各个基站通过对发射功率的限制， 不 会受到相邻基站信号的干扰， 或者干扰很小。
另外， 子载波的分组以及主子载波和副子载波的划分可固定不变， 也可才艮据时间进行动态变化， 即子载波的分组以及主子载波和副子载波 的划分可随意变化， 只要保证在同一时间内相邻小区没有同时使用同一 子载波即可。 例如， 有 6个子载波， 相应标识分别为 1、 2、 3、 4、 5和 6, 在一个时间段内， 将标识为 1和 2的子载波划分为一组子载波， 将 标识为 3和 5的子载波划分为一组子载波， 将标识为 4的子载波划分为 一组子载波， 将标识为 6的子载波划分为一组子载波， 小区 1以标识为 1和 2的这组子载波作为本小区的主子载波， 其余子载波作为本小区的 副子载波,相邻小区 2以标识为 4的这组子载波作为本小区的主子载波， 其余子载波作为本小区的副子载波； 一段时间后， 可将这 5个子载波重 新分组， 将标识为 2和 5的子载波划分为一组子载波， 将标识为 4和 6 的子载波划分为一组子载波， 将标识为 1的子载波划分为一组子载波， 将标识为 3的子载波划分为一组子载波， 小区 1以标识为 4和 6的这组 子载波作为本小区的主子载波， 其余子载波作为本小区的副子载波， 相 邻小区 2以标识为 3的这组 '子载波作为本小区的主子载波， 其余子载波 作为本小区的副子载波。
考虑到系统的容量、频谱效率等宏观问题， 如图 5示出的 OFDM频 率分组划分形成的示范性组网图， 分组的典型值可取 3 , 此时的组网形 式也即为蜂窝网 （每三个小区两两相邻）， 这种形式蜂窝网可使得系统 容量达到最大， 频谱效率达到最高。 不难理解， 若要使频谱效率达到最 高， 对于子载波分为 3组， 由相邻的小区分别采用不同的子载波组。 另 外， N也可取其他值， 如 4、 5、 6、 7、 8等等。
下面参见图 6, 对本发明正交频分复用调制方法来实现对各个子载 波功率控制、 以及进而实现本发明 OFDM 系统频率复用的方法进行说 明。
在 OFDM的信号发送方法中， OFDM的调制过程包括以下步骤： 步骤 1 : 经过调制后的用户数据信元进行 OFDM操作时， 首先进行 串并变换， 将输入的串行数据信元转换为 n路并行子数据流， 设 n路并 行子数据流为 f ( 1 ) ,f ( 2 ) . . .f ( n )。
步骤 2: 经过串并变换后的 n路子数据流分成 N个组， N的取值从 1到最大子载波数； （分为 N个组，每组可以包括 m个子载波， m <= N <= n ), 将这 N个组记为： g ( 1 ) ,g ( 2 ) ...g ( N )o
步驟 3: 每个组的各个子数据流乘上一个功率系数， 用于调整所映 射的各个子载波的发射功率， 这可以由子载波功率系数调节器实现。 不 同组可以采用不同的功率系数门限。
并且， 所述各路功率系数被控制有各自的功率系数门限， 这可以由 子载波功率门限控制逻辑器实现。 其中， 可以控制一部分组的子数据流 所乘的功率系数的门限高于其他组子数据流的功率系数门限， 如， 将功 率系数门限分为两部分， 一部分功率系数门限为 G1 , 另一部分为 G2， 且 G1>G2。 可以将 G1 所对应的子载波组作为本小区的主子载波， G2 对应的子载波组作为副子载波。 这样当不同小区选用不同主子载波时， 便可实现本发明的 OFDM系统的频率复用方式。
例如， 参考图 4， 当小区 1采用了子载波 g ( 1 )组功率门限为 Gl， 其他子载波组功率门限为 G2; 相邻小区 2采用了 g ( 2 )组功率门限为 G1 , 其他子载波组功率门限为 G2; 相邻小区 3采用了 g ( 3 )組功率门 限为 G1 , 其他子载波组功率门限为 G2， 就可以实现图 4所示的 OFDM 频率复用。
需要说明的是， 要实现图 4的蜂窝网 （每三个小区两两相邻） 中频 •普使用率最高， 需要将子载波分为 3组， 由两两相邻的三个小区分别采 用不同的子载波组， 要实现这样的子载波分配， 就需要所述三个小区分 别对应的功率系数门限高的子数据流路数的和与所述多路子数据流总 路数相同。
步骤 4: n路并行数据流根据一定的方式进行交织和排列， 交织排列 的方式决定了子载波的映射方式。
步骤 5 : 交织排列后的并行数据流进行傅立叶反变换 （可以是 IFFT/IDFT ), 映射为 n路数据对应的 n个子载波。
步骤 6: 每个子载波加循环前缀 CP, 用于克服符号间串扰， 然后进 行并串变换为一路， 完成 OFDM操作。
其中，对应步骤 4的交织排列、步骤 6的加循环前缀是可选的步骤， 另外， 步骤 4所述的交织排列也可以在步骤 1之后。
' 为了实现各个子载波功率被控下可调整， 还相应的提供了设备， 参 见图 6， 包括： 串并变换器， 用于将输入的数据串并转换为多路并行数 据输出； 子载波功率系数调节器， 用于将串并变换器输出的多路并行数 据流在由傅立叶反变换接收之前， 对各路并行数据流乘上一个功率系 数， 该功率系数用于对各路数据流所映射的子载波功率的调整； 子载波 功率门限控制逻辑器， 用于对所述各路子载波功率系数的门限进行控 制， 具体来说， 子载波功率门限控制逻辑器为每一路子载波所乘的功率 系数分别提供一个门限， 限制功率系数只能在其门限内进行变化， 具体 可参见上述步驟 3提到的使用功率系数门限的例子， 此处不再赘述； 傅 立叶反变换变换器， 用于接收所述多路数据流进行傅立叶反变换后映射 到对应的多路子载波上； 并串变换器， 用于接收傅立叶反变换变换器输 出的多路子载波， 并串变换为一路输出。 如图， 还可包括， 用于将傅立 叶反变换变换器要接收的数据流进行交织排列的交织 /排列单元、用于将 并串变换器要转换的每一路子载波加入循环前綴的加循环前缀单元。
可将本发明所提出的正交频分复用接入设备应用到发射机中。 对于 本领域人员而言， 将正交频分复用接入设备并入发射机的方式是清楚 的， 因此对此并不赘述。
使用本发明方法来承载无线信道时， 针对全覆盖类型信道， 如广播 信道、 公共控制信道等， 可设置这些信道只使用本小区的主子载波， 采 用较高的发射功率， 相邻小区的覆盖区域虽有重叠， 但相互间干扰比较 低， 有利于终端的小区选择、 切换和正确接收公共控制信息。 另外为了 保证信令的可靠性， 也可只使用主子载波承载信令。
可设置终端位于所在小区边缘区域时， 业务信道只使用主子载波， 由于相邻小区的主子载波互不重叠， 能够降 4氏相邻小区间的相互干 ί尤， 提高通信质量。 小区边缘区域可预先定义， 如将基站覆盖范围的 75%以 外视为小区的边缘区域。
可设置终端距离基站较近时， 同时使用主子载波和副子载波， 实现 高速数据和多媒体业务的传输。 由于副子载波的发射功率相对较低， 降 低了对相邻小区的干扰， 提高了频谱的利用效率。 该距离可为设定的范 围，如小区覆盖区域的 75%之内，如果终端与基站的距离在设定范围内， 则均可视为终端与基站相距较近。
以上所述仅为本发明的较佳实施例而已， 并不用以限制本发明， 凡 在本发明的精神和原则之内， 所作的任何修改、 等同替换、 改进等， 均 应包含在本发明的保护范围之内。

Claims

权利要求书
1、 一种实现正交频分复用 OFDM系统频率复用的方法， 各个小区 基站采用 OFDM系统， 相邻小区采用相同的频谱资源， 其特征在于， 各 个小区基站发送数据过程中， 在进行 OFDM操作时， 包括以下步骤： 将输入的串行数据流转换为多路并行子数据流；
将各路子数据流与用于对所映射的子载波进行功率调整的功率系数 的乘积作傅立叶反变换映射到所述各路子数据流对应的子载波上； 所述 各路子数据流的功率系数有各自的功率系数门限， 且至少一路子数据流 的功率系数门限与其他路数据流的功率系数门限不同；
将傅立叶反变换后的各路子载波并串转换为一路输出。
2、根据权利要求 1所述的方法， 其特征在于， 不同相邻小区对应功 率系数门限高的子数据流映射的子载波互不重叠。
3、根据权利要求 1所述的方法， 其特征在于， 所述各路功率系数门 P艮根据时间的变化进行变化。
4、 才艮据权利要求 1所述的方法， 其特征在于， 进一步包括： 当采用 蜂窝网方式组网时， 两两相邻的三个小区中， 所述三个小区分别对应的 功率系数门限高的子数据流路数之和， 与所述多路子数据流总路数相 同。
5、才艮据权利要求 1所述的方法， 其特征在于： 在将输入的串行数据 流转换为多路并行子数据流后， 或将各路子数据流作傅立叶反变换前， 进一步包括： 对各路子数据流进行交织排列操作。
6、根据权利要求 1或 5所述的方法， 其特征在于： 将傅立叶反变换 后的各路子载波并串转换为一路之前， 进一步包括： 各路子载波加循环 前缀。
7、一种正交频分复用调制方法，其特征在于，该方法包括以下步骤： 将输入的串行数据流转换为多路并行子数据流；
将各路子数据流与用于对所映射的子载波进行功率调整的功率系数 的乘积作傅立叶反变换映射到所述各路子数据流对应的子载波上， 其中 所述各路子数据流的功率系数有各自的功率系数门限， 且至少一路子数 据流的功率系数门限与其他路数据流的功率系数门限不同；
将傅立叶反变换后的各路子载波并串转换为一路输出。
8、 一种正交频分复用接入设备， 包括：
串并变换器，用于将输入的数据串并转换为多路并行子数据流输出； 傅立叶反变换变换器， 用于接收所述多路数据流进行傅立叶反变换 映射到对应的多路子载波上；
并串变换器， 用于接收傅立叶反变换变换器输出的多路子载波， 并 串变换为一路输出； 其特征在于， 还包括：
子载波功率系数调节器， 用于将串并变换器输出的多路并行子数据 流在由傅立叶反变换变换器接收之前， 对各路并行子数据流分别乘上用 于对所映射的子载波进行功率调整的功率系数；
子载波功率门限控制逻辑器， 用于对所述各路子数据流所乘的功率 系数的门限进行控制。
9、 根据权利要求 8所述的设备， 其特征在于， 进一步包括： 交织排 列器， 用于将傅立叶反变换变换器要接收的数据流进行交织排列。
10、 根据权利要求 8或 9所述的设备， 其特征在于， 进一步包括： 加循环前缀单元， 用于将并串变换器要转换的每一路子载波加入循环前 缀。
11、 一种发射机， 其特征在于， 该发射机包括如权利要求 8-10中任 一项所述的正交频分复用接入设备。
PCT/CN2006/001546 2005-07-01 2006-07-03 Méthode de multiplexage de fréquence orthogonale, de modulation et dispositif d’accès dans système ofdm WO2007003133A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN200510080443.7 2005-07-01
CN2005100804437A CN1893410B (zh) 2005-07-01 2005-07-01 实现正交频分复用系统的频率复用方法及接入设备

Publications (1)

Publication Number Publication Date
WO2007003133A1 true WO2007003133A1 (fr) 2007-01-11

Family

ID=37597926

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2006/001546 WO2007003133A1 (fr) 2005-07-01 2006-07-03 Méthode de multiplexage de fréquence orthogonale, de modulation et dispositif d’accès dans système ofdm

Country Status (2)

Country Link
CN (1) CN1893410B (zh)
WO (1) WO2007003133A1 (zh)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8259828B2 (en) 2008-02-12 2012-09-04 Mediatek Inc. Sub-carrier alignment mechanism for OFDM multi-carrier systems

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1983918A (zh) * 2005-12-12 2007-06-20 华为技术有限公司 实现软频率复用、数据发送的方法及接入设备
CN101242625B (zh) * 2007-02-06 2011-08-03 华为技术有限公司 一种控制信道资源映射的方法、系统及装置
CN101374340B (zh) * 2007-08-23 2012-02-29 中兴通讯股份有限公司 实现小区干扰协同的控制信道交织、解交织方法及其装置
CN102082592A (zh) * 2010-12-15 2011-06-01 北京理工大学 基于高速总线和gpu的快跳频多发多收系统通信方法
AU2016255500B2 (en) 2015-04-29 2020-04-30 Interdigital Patent Holdings, Inc. Methods and devices for sub-channelized transmission schemes in WLANS

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000224133A (ja) * 1999-01-28 2000-08-11 Matsushita Electric Ind Co Ltd 周波数分割多重信号送受信装置と送受信方法
CN1381112A (zh) * 2000-05-29 2002-11-20 松下电器产业株式会社 多载波通信装置和多载波通信方法
WO2004051900A1 (ja) * 2002-12-02 2004-06-17 Ntt Docomo, Inc. 直交周波数マルチキャリア送信装置及び送信方法
KR20050003904A (ko) * 2003-07-04 2005-01-12 에스케이 텔레콤주식회사 간섭이 최소화된 직교 주파수 분할 다중화 방식의 무선통신 시스템 및 그 방법

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FI102703B1 (fi) * 1997-03-27 1999-01-29 Nokia Telecommunications Oy Kanavan allokointimenetelmä
WO2004032375A1 (ja) * 2002-10-07 2004-04-15 Fujitsu Limited Ofdm-cdmaにおける送信電力制御方法および送信電力制御装置
KR100557830B1 (ko) * 2003-05-30 2006-04-05 재단법인서울대학교산학협력재단 직교 주파수 분할 다중 무선 통신 시스템용 리소스할당방법과 이를 이용한 전송신호 생성방법 및 그 송신기
EP1530388A1 (en) * 2003-11-06 2005-05-11 Matsushita Electric Industrial Co., Ltd. Transmission power level setting during channel assignment for interference balancing in a cellular wireless communication system

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000224133A (ja) * 1999-01-28 2000-08-11 Matsushita Electric Ind Co Ltd 周波数分割多重信号送受信装置と送受信方法
CN1381112A (zh) * 2000-05-29 2002-11-20 松下电器产业株式会社 多载波通信装置和多载波通信方法
WO2004051900A1 (ja) * 2002-12-02 2004-06-17 Ntt Docomo, Inc. 直交周波数マルチキャリア送信装置及び送信方法
KR20050003904A (ko) * 2003-07-04 2005-01-12 에스케이 텔레콤주식회사 간섭이 최소화된 직교 주파수 분할 다중화 방식의 무선통신 시스템 및 그 방법

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8259828B2 (en) 2008-02-12 2012-09-04 Mediatek Inc. Sub-carrier alignment mechanism for OFDM multi-carrier systems

Also Published As

Publication number Publication date
CN1893410B (zh) 2010-04-21
CN1893410A (zh) 2007-01-10

Similar Documents

Publication Publication Date Title
CN111384998B (zh) 一种基于相同ofdm系统的宽带电力线载波和宽带无线双模通信系统
JP5379269B2 (ja) 受信装置および受信方法
US8811141B2 (en) OFDM/OFDMA frame structure for communication systems
WO2006058491A1 (fr) Procede permettant de reutiliser une frequence douce dans un dispositif de communication sans fil et son dispositif
EP1941771B1 (en) Shared signaling channel
RU2328822C1 (ru) Устройство и способ для регулирования мощности передачи в системах связи, использующих схемы множественного доступа с ортогональным частотным разделением каналов
JP4864008B2 (ja) マルチセル直交周波数分割多元接続システムにおけるキャリア割り当て方法
KR101147492B1 (ko) 광대역 무선 통신에서의 신호 생성과 정보 전송 방법, 시스템 및 장치
WO2007068198A1 (fr) Procédé et dispositif d&#39;accès permettant le multiplexage logiciel de fréquences et la transmission de données
RU2472292C2 (ru) Устройство и способ назначения поднесущих при кластерном мультиплексировании с ортогональным частотным разделением и дискретным преобразованием фурье
KR20130022523A (ko) 다수의 직교 주파수 분할 다중 파라미터 셋을 지원하는 무선통신 시스템에서 통신 방법 및 장치
KR20040028445A (ko) 주파수분할다중접속 이동통신시스템에서 가상 셀의 자원할당장치 및 방법
Bellanger FS-FBMC: A flexible robust scheme for efficient multicarrier broadband wireless access
KR20070034905A (ko) 광대역 무선 접속 통신 시스템에서 주파수 자원 운용 장치및 방법
WO2007003133A1 (fr) Méthode de multiplexage de fréquence orthogonale, de modulation et dispositif d’accès dans système ofdm
KR20170043037A (ko) 다중반송파 무선 통신 시스템에서의 반복전송 운용 방안 및 장치
CN1953364B (zh) 一种多载波系统小区内的信道实现方法
CN100536453C (zh) Ofdm系统中自适应导频插入的方法
Dalela et al. Beam Division Multiple Access (BDMA) and modulation formats for 5G: Heir of OFDM?
WO2007076684A1 (fr) Procede et dispositif d&#39;acces multiple par repartition en frequence orthogonale entrelacee
WO2006116909A1 (fr) Systeme et procede de realisation d&#39;un multiplexage logiciel dans le temps dans un systeme de communication sans fil
US20050237922A1 (en) Virtual side channels for digital wireless communication systems
RU2450463C2 (ru) Передача данных в многопользовательской системе ofdm с адаптивной модуляцией
KR101359840B1 (ko) 직교 주파수 분할 다중 방식을 사용하는 통신 시스템에서자원 배치 장치 및 방법
Guo Research on Key Technologies of 4G-LTE Uplink Physical Link

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application
NENP Non-entry into the national phase

Ref country code: DE

WWW Wipo information: withdrawn in national office

Country of ref document: DE

122 Ep: pct application non-entry in european phase

Ref document number: 06753090

Country of ref document: EP

Kind code of ref document: A1