Publication number | US20020097779 A1 |

Publication type | Application |

Application number | US 09/767,953 |

Publication date | Jul 25, 2002 |

Filing date | Mar 27, 2001 |

Priority date | Dec 2, 1997 |

Also published as | DE10075378T1, DE69838242D1, DE69838242T2, DE69840883D1, DE69840900D1, EP0921652A2, EP0921652A3, EP0921652B1, EP1499053A2, EP1499053A3, EP1501224A2, EP1501224A3, EP1816773A2, EP1816773A3, EP1816773B1, EP1816774A2, EP1816774A3, EP1816774B1, EP1819081A2, EP1819081A3, EP1819081B1, EP1819082A2, EP1819082A3, EP1819082B1, EP1819083A2, EP1819083A3, EP1819083B1, EP2251998A2, EP2251998A3, EP2251998B1, EP2262141A1, US6222873, US6449306, US20140126611, USRE40385, USRE44507, USRE44635 |

Publication number | 09767953, 767953, US 2002/0097779 A1, US 2002/097779 A1, US 20020097779 A1, US 20020097779A1, US 2002097779 A1, US 2002097779A1, US-A1-20020097779, US-A1-2002097779, US2002/0097779A1, US2002/097779A1, US20020097779 A1, US20020097779A1, US2002097779 A1, US2002097779A1 |

Inventors | Seung Chan Bang, Jae Ryong Shim, Ki Chul Han, Jung Im Kim, Tae Joong Kim |

Original Assignee | Electronics And Telecommunications Research Center |

Export Citation | BiBTeX, EndNote, RefMan |

Referenced by (6), Classifications (13), Legal Events (5) | |

External Links: USPTO, USPTO Assignment, Espacenet | |

US 20020097779 A1

Abstract

An orthogonal complex spreading method for a multichannel and an apparatus thereof are disclosed. The method includes the steps of complex-summing α_{n1}W_{M,n1}X_{n1 }which is obtained by multiplying an orthogonal Hadamard sequence W_{M,n1 }by a first data X_{n1 }of a n-th block and α _{n2}W_{M,n2}X_{n2 }which is obtained by multiplying an orthogonal Hadamard sequence W_{1,n2 }by a second data X_{n2 }of a n-th block; complex-multiplying α_{n1}W_{M,n1}X_{n1}+jα_{n2}W_{M,n2}X_{n2 }which is summed in the complex type and W_{M,n3}+jPW_{M,n4 }of the complex type using a complex multiplier and outputting as an in-phase information and quadrature phase information; and summing only in-phase information outputted from a plurality of blocks and only quadrature phase information outputted therefrom and spreading the same using a spreading code.

Claims(40)

complex-summing α_{n1}W_{M,n1}X_{n1 }which is obtained by multiplying an orthogonal Hadamard sequence W_{M,n1 }by a first data X_{n1}, and gain α_{n1}, of a n-th block and α_{n2}W_{M,n2}X_{n2 }which is obtained by multiplying an orthogonal Hadamard sequence W_{M,n2 }by a second data X_{n2 }and gain α_{n2 }of a n-th block;

complex-multiplying α_{n1}W_{M,n1}X_{n1}+jα_{n2}W_{M,n2}X_{n2 }which is summed in the complex type and W_{M,n3}+jW_{M,n4 }of the complex type using a complex multiplier and outputting as an in-phase information and quadrature phase information; and

summing only in-phase information outputted from a plurality of blocks and only quadrature phase information outputted therefrom and spreading the same using a spreading code.

a plurality of complex multiplication blocks for distributing the data of the multichannel and complex signal α_{n1}W_{M,n1}X_{n1}+jα_{n2}W_{M,n2}X_{n2 }of which α_{n1}W_{M,n1}X_{n1 }which is obtained by multiplying the orthogonal Hadamard sequence W_{M,n1 }with the first data X_{n1 }of the n-th block and the gain α_{n1 }and α_{n2}W_{M,n2}X_{n2 }which is obtained by multiplying the orthogonal Hadamard sequence W_{M,n2 }with the second data X_{n2 }of the n-th block and the gain α_{n2 }are constituents, are complex-multiplied by W_{M,n3}+jW_{M,n4 }using the complex multiplier;

a summing unit for summing only the in-phase information outputted from each block of the plurality of the complex multiplication blocks and summing only the quadrature phase information outputted from each block of the plurality of the complex multiplicator blocks; and

a spreading unit for multiplying the in-phase information and the quadrature phase information which are summed by the summing unit by the spreading code and outputting an I channel and a Q channel.

a first multiplier for multiplying the first data X_{n1 }of a corresponding block by the orthogonal Hadamard sequence W_{M,n1; }

a second multiplier for multiplying the output signal from the first multiplier by the gain α_{n1; }

a third multiplier for multiplying the second data X_{n2 }by the orthogonal Hadamard sequence W_{M,n2; }

a fourth multiplier for multiplying the output signal from the third multiplier by the gain α_{n2; }

fifth and sixth multipliers for multiplying the output signal α_{n1}W_{M,n1}X_{n1 }from the second multiplier and the output signal α_{n2}W_{M,n2}X_{n2 }from the fourth multiplier by the orthogonal Hadamard sequence W_{M,n3; }

seventh and eighth multipliers for multiplying the output signal α_{n1}W_{M,n1}X_{n1 }from the second multiplier and the output signal α_{n2}W_{M,n2}X_{n2 }from the fourth multiplier by the orthogonal Hadamard sequence W_{M,n4; }

a first adder for summing the output signal (ac) from the fifth multiplier and the minus output signal (−bd) from the eighth multiplier and outputting an in-phase information (ac−bd); and

a second adder for summing the output signal (bc) from the sixth multiplier and the output signal (ad) from the seventh multiplier and outputting a quadrature phase information (bc+ad).

complex-summing α_{n1}W_{M,n1}X_{n1 }which is obtained by multiplying a predetermined orthogonal Hadamard sequence W_{M,n1 }by a data X_{n1 }and a gain α_{n1 }and α_{n2}W_{M,n2}X_{n2 }which is obtained by multiplying the orthogonal Hadamard sequence W_{M,n2 }of the second block by a predetermined data X_{n2 }and a gain α_{n2 }in the first block during a multichannel data distribution;

summing only the in-phase information based on the output signals from a plurality of other channels from two blocks and summing only the quadrature phase information; and complex-multiplying

which are summed in the complex type and W_{M,I}+jPW_{M,Q }which are formed of P representing a predetermined sequence or a spreading code or a predetermined integer using a complex multiplier and W_{M,I }and W_{M,Q }which are the orthogonal Hadamard sequences, and outputs the signal as an in-phase information and a quadrature phase information.

a first multiplier for multiplying the first data X_{n1 }of a corresponding block by the gain α_{n1; }

a second multiplier for multiplying the output signal from the first multiplier by the orthogonal Hadamard sequence W_{M,n1; }

a third multiplier for multiplying the second data X_{n2 }by the gain α_{n2; }

a fourth multiplier for multiplying the output signal from the third multiplier by the orthogonal Hadamard sequence W_{M,n2; }

fifth and sixth multipliers for multiplying the output signal α_{n1}W_{M,n1}X_{n1 }from the second multiplier and the output signal α_{n2}W_{M,n2}X_{n2 }from the fourth multiplier by the orthogonal Hadamard sequence W_{M,I; }

seventh and eighth multipliers for multiplying the output signal α_{n1}W_{M,n1}X_{n1 }from the second multiplier and the output signal α_{n2}W_{M,n2}X_{n2 }from the fourth multiplier by the orthogonal Hadamard sequence W_{M,Q; }

a first adder for summing the output signal (ac) from the fifth multiplier and the minus output signal (−bd) from the eighth multiplier and outputting an in-phase information (ac−bd); and

a second adder for summing the output signal (bc) from the sixth multiplier and the output signal (ad) from the seventh multiplier and outputting a quadrature phase information (bc+ad).

first and second Hadamard sequence multipliers for allocating the multichannel to a predetermined number of channels, splitting the same into two groups and outputting α_{n1}W_{M,n1}X_{n1 }which is obtained by multiplying the data X_{n1 }of each channel by the gain α_{n2 }and the orthogonal Hadamard sequence W_{M,n1};

a first adder for outputting

which is obtained by summing the output signals from the first Hadamard sequence multiplier;

a second adder for outputting

which is obtained by summing the output signals from the second Hadamard sequence multiplier;

a complex multiplier or receiving the output signal from the first adder and the output signal from the second adder in the complex form of

and complex-multiplying W_{M,I}+jPW_{M,Q }which consist of the orthogonal Hadamard code W_{M,I}, and the permutaed orthogonal Hadamard code PW_{M,Q }that W_{M,Q }and a predetermined sequence P are complex-multiplied;

a spreading unit for multiplying the output signal from the complex multiplier by the spreading code;

a filter for filtering the output signal from the spreading unit; and

a modulator for multiplying and modulating the modulation carrier wave, summing the in-phase signal and the quadrature phase signal and outputting a modulation signal of the real number.

Description

[0001] 1. Field of the Invention

[0002] The present invention relates to an improved orthogonal complex spreading method and apparatus for multiple channels. The invention is capable of the following:

[0003] decreasing a peak power-to-average power ratio by introducing an orthogonal complex spreading structure and spreading input signals using a spreading code; implementing a structure capable of spreading complex output signals using a spreading code by adapting a permuted orthogonal complex spreading structure for a complex-type multi-channel input signal with respect to the summed values; and decreasing a phase dependency of an interference based on a multipath component (when there is an one chip difference) of a self signal, which is a problem that is not overcome by a permuted complex spreading modulation method, nor by a combination of an orthogonal Hadamard sequence.

[0004] 2. Description of the Prior Art

[0005] In the area of mobile communication systems, it is well known in the art that linear and non-linear distortions affect power amplifiers. The statistical characteristic of a peak power-to-average power ratio has a predetermined interrelationship for non-linear distortion.

[0006] The third order non-linear distortion, which is one of the factors affecting the power amplifier, causes an inter-modulation problem in an adjacent frequency channel. The inter-modulation problem created by a high peak amplitude, which increases the adjacent channel power (ACP), so that there is a predetermined limit for selecting the amplifier. In particular, the Code Division Multiple Access (CDMA) system requires a very strict condition with respect to linearity of a power amplifier. Therefore, the above-described condition is a very important factor.

[0007] In accordance with International Standards 97 and 98, the FCC stipulates a condition on the adjacent channel power (ACP). In order to satisfy the above-described condition, the bias of the Radio Frequency (RF) power amplifier has to be limited.

[0008] According to the current IMT-2000 system standard recommendation, a plurality of CDMA channels are recommended. In case a plurality of channels are provided, the peak power-to-average power ratio is considered an important factor for increasing the efficiency of the modulation method.

[0009] The IMT-2000, which is a third generation mobile communication system, has received a lot of attention as the next generation communication system following the digital cellular system, personal communication system, and etc. The IMT-2000 will be commercially available as a wireless communication system, which has a high capacity and performance for supporting various multimedia services and international roaming services, etc.

[0010] Many countries have proposed utilizing IMT-2000 systems that would require high data transmission rates for internet service or electronic commercial activity. This is directly related to the power efficiency of a RF amplifier.

[0011] The IMT-2000 modulation method based on CDMA technology is classified as a pilot channel and symbol method. The pilot channel method is directed to the CDMA ONE introduced in North America. The pilot symbol method is directed to the NTT-DOCOMO and ARIB proposal introduced in Japan and to the FMA2 proposal introduced in Europe.

[0012]FIG. 1 illustrates a prior art complex spreading method based on a CDMA ONE method.

[0013] The CDMA ONE is implemented by using a complex spreading method. The pilot channel and the fundamental channel spread by a Walsh code **1** are summed thereby forming in-phase information. The supplemental channel spread by a Walsh code **2** and the control channel spread by a Walsh code **3** are also summed thereby forming quadrature-phase information. In addition, the in-phase and quadrature-phase information are complex-spread by PN codes.

[0014] As shown, the signals from a fundamental channel **1**A, a supplemental channel **1**B, and a control channel **1**C are multiplied by Walsh codes W_{4,1}, W_{4,2 }and W_{4,3}, which is performed by each multiplier (**20**A, **20**B and **20**C) of multiplication unit **20** through a signal-mapping unit **10**. The pilot signal and the signals multiplied by the Walsh codes are respectively multiplied by channel gains A**0**, A**1**, A**2** and A**3** in channel gain multiplication unit **30**.

[0015] In a summing unit **40**, the pilot signal and the fundamental channel signal are summed by a first adder **40** *a *thereby obtaining in-phase information. Additionally, the supplemental channel signal and the control channel signal are summed by a second adder **40** *b *thereby obtaining quadrature phase information.

[0016] The in-phase and quadrature-phase information are then multiplied by a PN**1** and PN**2** code by spreading unit **50**. The identical phase information multiplied by the PN**2** code is then subtracted by the in-phase information multiplied by the PN**2** code is outputted as an I channel signal. The quadrature-phase information multiplied by the PN**1** code and the in-phase information multiplied by the PN**2** code are summed and then outputted through as a Q channel signal a delay unit **60**.

[0017]FIG. 2A is a view illustrating a constellation of signals in a phase domain before pulse shaping in a prior art CDMA ONE method and FIG. 2B is a view illustrating a constellation of signals in a phase domain after shaping in prior art CDMA ONE method.

[0018] In the CDMA ONE, the left and right information, namely, the in-phase information (I channel) and the upper and lower information, namely, the quadrature-phase information (Q channel) pass through the actual pulse-shaping filter thereby causing a peak power.

[0019] In view of the crest factor and the statistical distribution of the power amplitude, the peak power is generated in a vertical direction so that the problems such as irregular spreading of code and crosstalk occur.

[0020] Accordingly, it is an object of the present invention to provide an orthogonal complex spreading method and apparatus for multiple channels that overcomes the aforementioned problems encountered in the prior art.

[0021] The peak power-to-average power ratio is important in IMT-2000 system since the CDMA system requires a strict condition for linearity of a power amplifier. In particular, the IMT-2000 system provides multiple channels, which transmit signals simultaneously, and the peak power-to-average power ratio is related to the efficiency of the modulation method.

[0022] It is another object of the present invention to provide an orthogonal complex spreading method and apparatus for multiple channels, which have an excellent power efficiency compared with the complex spreading methods introduced in the CDMA-ONE of the United States and the W-CDMA. Additionally, the invention is capable of resolving a power unbalance problem of an in-phase and quadrature-phase channel as well as the complex spreading method.

[0023] It is still another object of the present invention to provide an orthogonal complex spreading method and apparatus for multiple channels, which is capable of maintaining a stable low peak power-to-average power ratio.

[0024] Additionally, in the present invention a spreading operation is implemented as follows: multiplying predetermined channel data among data of a multichannel by an orthogonal Hadamard sequence and a gain; multiplying data of another channel by an orthogonal Hadamard sequence and a gain; summing the information of the two channels in complex type; multiplying the summed information of the complex type by the orthogonal Hadamard sequence of the orthogonal type; obtaining a complex type; summing a plurality of channel information of the complex type in the above-described manner; and multiplying the information of the complex type of the multichannel by a spreading code sequence.

[0025] Furthermore, it is an object of the present invention to decrease the probability that the power drops to zero by doing the following: preventing the FIR filter input state from exceeding 90° in an earlier sample state; increasing the power efficiency and decreasing the consumption of bias power for a back-off of the power amplifier; and saving the power of a battery.

[0026] It is still another object of the present invention to provide an orthogonal complex spreading method and apparatus for a multichannel, which is capable of implementing a Permuted Orthogonal Complex QPSK (POCQPSK) which is another modulation method that has a power efficiency similar with the Orthogonal Complex QPSK (OCQPSK).

[0027] In order to achieve the above objects, there is an orthogonal complex spreading method that is provided for a multichannel which includes the following steps:

[0028] complex-summing α_{n1}W_{M,n1}X_{n1 }which is obtained by multiplying an orthogonal Hadamard sequence W_{M,n1 }by a first set of data of X_{n1 }of a n-th block, and a α_{n2}W_{M,n2}X_{n2}, which is obtained by multiplying an orthogonal Hadamard sequence W_{M,n2 }by a second set of data of X_{n2 }of a n-th block; complex-multiplying α_{n1}W_{M,n1}X_{n1}+jα_{n2}W_{M,n2}X_{n2}, which is summed in the complex type, and W_{M,n3}+jW_{M,n4 }of the complex type using a complex multiplier and outputting in-phase and quadrature-phase information; summing only in-phase information outputted from a plurality of blocks and only quadrature-phase information outputted therefrom; and spreading the same using a spreading code.

[0029] In order to achieve the above objects, there is provided an orthogonal complex spreading apparatus according to a one embodiment of the present invention which includes the following: a plurality of complex multiplication blocks for distributing the data of the multichannel and complex-multiplying α_{n1}W_{M,n1}X_{n1}+jα_{n2}W_{n2}X_{M,n1 }in which α_{n1}W_{M,n1}X_{n1 }is obtained by multiplying the orthogonal Hadamard sequence W_{M,n1 }with the first set of data of X_{n1}, of the n-th block and the gain α_{n1 }and α_{n2}W_{M,n2}X_{n2 }which is obtained by multiplying the orthogonal Hadamard sequence W_{M,n2 }with the second set of data of X_{n2 }of the n-th block and the gain α_{n2 }and W_{M,n3}+W_{M,n4 }using the complex multiplier; a summing unit for summing only the in-phase information outputted from each block of the plurality of the complex multiplication blocks and summing only the quadrature-phase information; and a spreading unit for multiplying the in-phase and quadrature-phase information summed by the summing unit with the spreading code and outputting an I channel and a Q channel.

[0030] In order to achieve the above objects, there is provided an orthogonal complex spreading apparatus according to another embodiment of the present invention, which includes the following: first and second Hadamard sequence multipliers for allocating the multichannel to a predetermined number of channels, splitting the same into two groups and outputting α_{n1}W_{M,n1}X_{n1, }which is obtained by multiplying the data X_{n1 }of each channel by the gain α_{n1 }and the orthogonal Hadamard sequence W_{M,n1}; a first adder for outputting

[0031]

[0032] which is obtained by summing the output signals from the first Hadamard sequence multiplier; a second adder for outputting

[0033]

[0034] which is obtained by summing the output signals from the second Hadamard sequence multiplier; a complex multiplier for receiving the output signal from the first and second adder in the complex form of

[0035]

[0036] and complex-multiplying W_{M,I}+jPW_{M,Q }where n=1 consists of the orthogonal Hadamard code W_{M,I }and the permuted orthogonal Hadamard code PW_{M,Q }where W_{M,Q }and a predetermined sequence P are complex-multiplied; a spreading unit for multiplying the output signal from the complex multiplier by the spreading code; a filter for filtering the output signal from the spreading unit; and a modulator for multiplying and modulating the modulation carrier wave, summing the in-phase and quadrature-phase signal and outputting a modulation signal of the real number.

[0037] Additional advantages, objects and other features of the invention will be set forth in the description which follows and will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.

[0038] The present invention will become more fully understood from the detailed description given below and the accompanying drawings, which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:

[0039]FIG. 1 is a block diagram illustrating a prior art multichannel complex spreading method of a CDMA ONE method;

[0040]FIG. 2A is a view illustrating a constellation of signals in a phase domain before pulse shaping in a prior art CDMA ONE method;

[0041]FIG. 2B is a view illustrating a constellation of signals in a phase domain after pulse shaping in a prior art CDMA ONE method;

[0042]FIG. 4 is a block diagram illustrating a multi-channel orthogonal complex spreading apparatus in accordance with one embodiment of the present invention;

[0043]FIG. 5A is a circuit diagram illustrating the complex multiplier of FIG. 4;

[0044]FIG. 5B is a circuit diagram illustrating the summing unit and spreading unit of FIG. 4;

[0045]FIG. 5C is a circuit diagram illustrating another embodiment of the spreading unit of FIG. 4;

[0046]FIG. 5D is a circuit diagram illustrating the filter and modulator of FIG. 4;

[0047]FIG. 6A is a view illustrating a constellation of signals in a phase domain before pulse shaping in an OCQPSK according to the present invention;

[0048]FIG. 6B is a view illustrating a constellation of signals in a phase domain after pulse shaping in an OCQPSK in accordance with the present invention;

[0049]FIG. 7 is a view illustrating a statistical distribution characteristic of power peak occurrences with respect to an average power between the prior art and the present invention;

[0050]FIG. 8 illustrates an example of an orthogonal Hadamard sequence in accordance with the present invention;

[0051]FIG. 9 is a circuit diagram illustrating a multichannel permuted orthogonal complex spreading apparatus in accordance with another embodiment of the present invention;

[0052]FIG. 10 is a circuit diagram illustrating the complex multiplier of FIG. 8;

[0053]FIG. 11 is a circuit diagram illustrating a multichannel permuted orthogonal complex spreading apparatus with two input channels in accordance with the present invention;

[0054]FIG. 12 is a circuit diagram illustrating a multichannel permuted orthogonal complex spreading apparatus with three input channels in accordance with the present invention;

[0055]FIG. 13A is a circuit diagram illustrating a multichannel permuted orthogonal complex spreading apparatus for a QPSK having a high transmission rate with the present invention;

[0056]FIG. 13B is a circuit diagram illustrating a multichannel permuted orthogonal complex spreading apparatus with four input channels in accordance with the present invention;

[0057]FIG. 14A is a circuit diagram illustrating a multichannel permuted orthogonal complex spreading apparatus for a multimedia service in accordance with the present invention;

[0058]FIG. 14B is a circuit diagram illustrating a multichannel permuted orthogonal complex spreading apparatus with five input channels in accordance with the present invention;

[0059]FIG. 15A is a phase trajectory view of an OCQPSK according to the present invention;

[0060]FIG. 15B is a phase trajectory view of a POCQPSK according to the present invention; and

[0061]FIG. 15C is a phase trajectory view of a prior art complex spreading method.

[0062] The complex summing unit and complex multiplier, according to the present invention, will be explained with reference to the accompanying drawings. In the present invention, assuming that two complex number (a+jb) and (c+jd) are used, where a, b, c and d represent predetermined real numbers, a complex summing unit outputs (a+c)+j(b+d) and a complex multiplier outputs ((a×c)-(b×d))+j((b×c)+(a×d)). The following items are defined for the invention: a spreading code sequence is defined as SC; information data is defined as X_{n1 }and X_{n2}; a gain constant is defined as α_{n1 }and α_{n2}; and an orthogonal Hadamard sequence is defined as W_{M,n}, W_{M,n2, }W_{M,n3, }W_{M,n4, }W_{M,I, }W_{M,Q, }where M represents a M×M Hadamard matrix and n**1**, n**2**, n**3** and n**4** represent an index of predetermined vectors of the Hadamard matrix. For example, n**3** represents a Hadamard vector, wherein W_{M,n3 }is a third vector value described in n-th block **100** *n *shown in FIG. 4.

[0063] The data X_{n1}, X_{n2}, W_{M,n1}, W_{M,n2, }W_{M,n3, }W_{M,n4, }W_{M,I}, and W_{M,Q }and spreading sequence SC are combined data consisting of +1 or -−1. α_{n1 }and α_{n2 }are real numbers.

[0064]FIG. 4 is a block diagram illustrating a multichannel orthogonal complex spreading apparatus, in accordance with one embodiment of the present invention.

[0065] As shown therein, there is provided a plurality of complex multipliers **100** through **100** *n*. In a complex multiplier **100** *n*, data X_{n1 }of a predetermined channel is multiplied by a gain α_{n1 }and an orthogonal Hadamard sequence W_{M,n1 }and data X_{n2 }of another channel is multiplied by a gain α_{n2 }and an orthogonal Hadamard sequence W_{M,n2. }The data from both channels are complex-summed and then the complex orthogonal Hadamard sequence W_{M,n3}+jW_{M,n4 }is multiplied by the complex-summed data α_{n1}W_{M,n1}X_{n1}+jα_{n2}W_{M,n2}X_{n2 }and the data of the other complex-multipliers are obtained in the same manner as described above. The summing unit **200** sums the output signals from complex multipliers **100** through **100** *n*. The spreading unit **300** multiplies the output signal from the summing unit **200** with a predetermined SC, thereby spreading the signal. A pulse-shaping filter **400** filters the data spread by the spreading unit **300**. A modulation wave multiplier **500** multiplies the output signal from the filter **400** with a modulation carrier wave e^{2πfct. }

[0066] As shown in FIG. 4, the first complex multiplier **100** complex-sums α_{11}W_{M,11}X_{11}, obtained by multiplying the orthogonal Hadamard sequence W_{M,11 }with the data X_{11 }of one channel and the gain α_{11, }and α_{12}W_{M,12}X_{12}, obtained by multiplying the orthogonal Hadamard sequence W_{M,12 }with the data X_{12 }of another channel and the gain α_{12. }The α_{11}W_{M,11}X_{11}+jα_{12}W_{M,12}X_{12 }is then multiplied by the complex-type orthogonal sequence W_{M,13}X_{11}+jW_{M,14 }at the complex multiplier **111**.

[0067] In addition, the n-th complex multiplier **100** *n *complex-sums α_{n1}W_{M,n1}X_{n1}, obtained by multiplying the orthogonal Hadamard sequence W_{M,n1 }with the data X_{n1 }of another channel and the gain α_{n1}, and α_{n2}W_{M,n2}X_{n2}, obtained by multiplying the orthogonal Hadamard sequence W_{M,n2 }with the data X_{n2 }of another channel and the gain α_{n2. }The α_{n1}W_{M,n1}X_{n1}+jα_{n2}W_{M,n2}X_{n2 }is complex-multiplied by the complex-type orthogonal sequence W_{M,n3}X_{11}+jW_{M,n4 }at the complex multiplier **100** *n. *

[0068] The complex multiplication data outputted from the n-number of the complex multipliers are summed at the summing unit **200**, and the spreading code SC is multiplied and spread by using the spreading unit **300**. The spread data is filtered at the pulse-shaping filter **600** and then multiplied by the modulation carried e^{j2πfct }at the multiplier **700**. The modulated signal is then processed by the function Re{*} **70** to thereby output the real data s(t) **80** through the antenna. Here, Re{*} **70** represents a function through which a predetermined complex number is processed as a real value.

[0069] The above-described function will be explained as follows:

[0070]

[0071] K represents a predetermined integer greater than or equal to 1; and n represents an integer greater than or equal to 1 and less than K and is identical with the index of each complex multiplier.

[0072] In FIG. 5A, the complex multiplier includes the following: a first multiplier **101**; a second multiplier **102**; a third multiplier **103**; a fourth multiplier **104**; fifth and sixth multipliers **105** and **106**; seventh and eighth multipliers **107** and **108**; a first adder **109**; and a second adder **110**.

[0073] The first and second multipliers **101** and **102** multiply the data X_{11}, by the orthogonal Hadamard sequence W_{M,11 }and the gain α_{11 }thereby obtaining α_{11}W_{M,11}X_{11}(=a). In addition, the third and fourth multipliers **103** and **104** multiply the orthogonal Hadamard sequence W_{M,12 }and the gain α_{12 }thereby obtaining α_{12}W_{M,12}X_{12}(=b). The fifth and sixth multipliers **105** and **106** multiply α_{11}W_{M,11}X_{11}(=a) and α_{12}W_{M,12}X_{12}(=b) by the orthogonal Hadamard sequence W_{M,13}(=c), respectively, for thereby obtaining α_{11}W_{M,11}X_{11}W_{M,13}(=ac) and α_{12}W_{M,12}X_{12}W_{M,13}(=bc). Additionally, the fifth and sixth multipliers **105** and **106** multiply α_{11}W_{M,11}X_{11}(=a) and α_{12}W_{M,12}X_{12}(=b) by the orthogonal Hadamard sequence W_{M,14}(=d) thereby obtaining α_{11}W_{M,11}X_{11}W_{M,14}(=ad) and α_{12}W_{M,12}X_{12}W_{M,14}(=bd). Thus, α_{12}W_{M,12}X_{12}W_{M,14 }is subtracted from α_{11}W_{M,11}X_{11}W_{M,13}. The second adder **110** then computes (α_{11}W_{M,11}X_{11}W_{M,14})+(α_{12}W_{M,12}X_{12}W_{M,13}) (ad+bc). Specifically, α_{11}W_{M,11}X_{11}W_{M,14}(=ad) is added with α_{12}W_{M,12}X_{12}W_{M,13}(=bc).

[0074] Referring back to FIG. 4, the first complex multiplier **100** is configured identically with the n-th complex multiplier **100** *n*. The expression “(a+jb)(c+jd)=ac−bd+j(bc+ad)” is obtained assuming that α_{11}W_{M,11}X_{11 }is “a”, α_{12}W_{M,12}X_{12 }is “b”, the orthogonal Hadamard sequence W_{M,13 }is “c”, and the orthogonal Hadamard sequence W_{M,14 }is “d”. Therefore, the signal outputted from the first complex multiplier **100** becomes the in-phase information “ac−bd” and the quadrature-phase information “bc+ad”.

[0075] In addition, FIG. 5B is a circuit diagram illustrating the summing and spreading unit of FIG. 4 and FIG. 5C is a circuit diagram illustrating another embodiment of the spreading unit of FIG. 4.

[0076] As shown therein, the summing unit **200** includes a first summing unit **210** for summing the in-phase information A_{1}(=(ac−bd)) outputted from a plurality of complex multipliers and a second summing unit **220** for summing the quadrature-phase information B_{1}(=(bc+ad)) outputted from the complex multipliers.

[0077] The spreading unit **300** includes first and second multipliers **301** and **302** for multiplying the output signals from the first adder **210** and the second adder **220** of the summing unit **200** by the SC. In other words, the in-phase and quadrature-phase signals are spread by the same SC.

[0078] In FIG. 5C, the spreading unit **300** includes the following: first and second multipliers **310** and **320**; third and fourth multipliers **330** and **340**; a first adder **350**; and a second adder **360**.

[0079] In the summing unit **200**, the in-phase and quadrature-phase information of the n-number of the complex multipliers are summed by the first and second adders **210** and **220**. In the spreading unit **300**, the in-phase value (g) and the quadrature phase value (h) from the summing unit **200** are multiplied by the first spreading code SC**1** (**1**) by the first and second multipliers **310** and **320** thereby obtaining gl and hl, in addition, the in-phase value (g) and the quadrature phase value (h) from the summing unit **200** are multiplied by the second spreading code SC**2**(m) by the third and fourth multipliers **330** and **340** thereby obtaining gm and hm. The first adder **350** computes gl-hm, in which hm is subtracted from gl, and the second adder **360** computes hl+gm, in which hl is added by gm.

[0080] In FIG. 5D, the filter **400** includes first and second pulse shaping filters **410** and **420** for filtering the I channel signal, which is the in-phase information shown in FIG. 5B and 5C, and the Q channel signal, which is the quadrature phase information signal. The modulation unit **500** includes the following: first and second multipliers **510** and **520** for multiplying the output signals from the first and second pulse shaping filters **410** and **420** by cos(2πf_{c}t) and sin(2πf_{c}t); and an adder **530** for summing the output signals from the first and second multipliers **510** and **520** and outputting a modulation data S(t).

[0081] In the present invention, the orthogonal Hadamard sequences may be replaced by a Walsh code or other orthogonal code.

[0082]FIG. 8 illustrates a 8×8 Hadamard matrix as an example of the Hadamard or Walsh code. The sequence vector of a k-th column or row is set to W_{k−1}. In this case, if k is 1, W_{k−1 }represents W_{0 }of the column or row and if k is 5, W_{k−1 }represents W_{4 }of the column or row.

[0083] In order to enhance the efficiency of the present invention, the orthogonal Hadamard sequence by which multiplies each channel data is multiplied, is determined as follows. In the M×M Hadamard matrix, the sequence vector of the k-th column or row is set to W_{k−1}. It can be set that W_{M,n1}=W_{0},W_{M,n2}=W_{2p }(where p represents a predetermined number of (M/2)-1), W_{M,n3}=W_{2n−2}, W_{M,n4}=W_{2n−1 }(where n represents the number of n-th blocks) so that α_{n1}W_{0}X_{n1}+jα_{n2}W_{2p}X_{n2 }is complex-multiplied by W_{2n−2}+jW_{2n−1. }

[0084] In FIG. 4, if only the first complex multipliers are used, then, only two channels are complex-multiplied, so that it can be determined that W_{M,11}=W_{0}, W_{M,12}=W_{2}, or W_{M,12}=W_{4}, W_{M,13}=W_{0}, and W_{M,14}=W_{1}, so that α_{11}W_{0}X_{11}+jα_{12}W_{2}X_{12 }or α_{11}W_{0}X_{11}+jα_{12}W_{4}X_{12 }is complex-multiplied by W_{0}+jW_{1. }

[0085] If the two complex multipliers are used in FIG. 4 it can be determined that W_{M,21}=W_{0}W_{M,22}=W_{4, }W_{M,23}=W_{2 }and W_{M,24}=W_{3}, so that α_{21}W_{0}X_{21}+jα_{22}W_{4}X_{22 }is complex-multiplied by W_{2}+jW_{3. }

[0086] Additionally, if spreading is implemented by using the SC, as shown in FIG. 5, one spreading code may be used. However, two spreading codes SC**1** and SC**2** may also be used, as shown in FIG. 5C.

[0087] In order to achieve the objects of the present invention, the combined orthogonal Hadamard sequence may be used instead of the orthogonal Hadamard sequence thereby removing phase dependency based on the interference generated in the multiple paths of self-signal and the interference other users.

[0088] If the sequence vector of the k-th column or row is set to W_{k−1 }in the M×M (M=8) Hadamard matrix, and the sequence vector of the m-th column or row is set to W_{m}, the combined orthogonal Hadamard vector W_{k−1/m−1 }is constructed by taking the first M/2 or the last M/2 from the vector W_{k−1, }and the last M/2 or the first M/2 from W_{m−1}. In the case of two channels, for example, it is possible to determine W_{M,11}=W_{0}, W_{M,12}=W_{4/1, }W_{M,1}=W_{0}, W_{M,Q}=W_{1/4, }so that α_{11}W_{0}X_{11}+jα_{12}W_{4/1}X_{12 }is complex-multiplied by W_{0}+jPW_{1/4. }

[0089] In the case of three channels, the summed value of α_{11}W_{0}X_{11}+jα_{12}W_{4/1}X_{12 }and α_{21}W_{2}X_{21 }are complex-multiplied by W_{0}+jPW_{1/4 }based on W_{M,11}=W_{0}, W_{M,12}=W_{4/1}, W_{M,21}=W_{2}, and W_{M,I}=W_{0}, W_{M,Q}=W_{1/4. }

[0090] In addition, in the case of two channels, to the summed value of α_{11}W_{0}X_{11}+jα_{12}W_{2/1}X_{12 }are complex-multiplied by W_{0}+jPW_{1/2 }based on W_{M,11}=W_{0}, W_{M,12}=W_{2/1}, and W_{M,I}=W_{0}, W_{M,Q}=W_{1/2. }

[0091] In addition, in the case of three channels, the summed value of α_{11}W_{0}X_{11}+jα_{12}W_{2/1}X_{12 }and α_{21}W_{4}X_{21 }are complex-multiplied by W_{0}+jPW_{1/2 }based on W_{M,11}=W_{0}, W_{M,12}=W_{2/1, }W_{M,21}=W_{4, }and W_{M,I}=W_{0}, W_{M,Q}=W_{1/2. }

[0092] Therefore, the cases of two and three channels have been explained. The two and three channels may be selectively used in accordance with the difference of the impulse response characteristic of the pulse shaping band pass filter.

[0093]FIG. 6A is a view illustrating a constellation of signals in a phase domain before pulse shaping in the OCQPSK in accordance with the present invention. FIG. 6B is a view of a constellation of signals in a phase domain after pulse shaping in an OCQPSK of FIG. 6A. FIG. 7 is a view illustrating a statistical distribution characteristic of power peak occurrences with respect to an average power between the prior art CDMA ONE and the present invention. The embodiment of FIG. 6A is similar to FIG. 2A. However, there is a difference in the signals after the pulse shaping. In FIG. 6B, the range of the upper and lower information (Q channel) and the left and right information (I channel) are saturated to their respective limits. This causes the difference of the statistical distribution of the peak power-to-average power.

[0094]FIG. 7 illustrates the peak power-to-average power ratio based on the result of the actual simulation between the present invention and the prior art. In order to provide identical conditions, the power level of the control or signal channel is set to the same the same power level of the communication channel (Fundamental channel, Supplemental channel; or In-phase channel, the Quadrature channel). Additionally, the power level of the pilot channel is set lower than the power level of the communication channel by 4dB. In the above-described condition, the statistical distributions of the peak power-to-average power are compared.

[0095] In case of OCQPSK, in accordance with the present invention, the comparison is implemented by using the first complex multiplier **100** and the n-th complex multiplier **100** *n *shown in FIG. 4. The first block **100** is implemented based on W_{M,11}=W_{0}, W_{M,12}=W_{4}, W_{M,13}=W_{0}, and W_{M,14}=W_{1}, and the n-th block **100** *n *is implemented based on W_{M,n1}=W_{0}, W_{M,n2}=W_{4, }W_{M,n3}=W_{2, }and W_{M,n4}=W_{3. }In addition, the SCI is used as spreading code, and the SC**2** is not used.

[0096] In the case of OCQPSK, the probability that the instantaneous power exceeds the average power value (0 dB) by 4 dB is 0.03%, and in the case of CDMA ONE, it is 0.9%. Therefore, the present invention has a very excellent characteristic with respect to the power efficiency and as a new modulation method, it reduces the crosstalk interference problem.

[0097]FIG. 9 illustrates a POCQPSK in accordance with the present invention. As shown therein, one or a plurality of channels are combined and complex-multiplied by the permuted orthogonal Hadamard code and then are spread by the spreading code.

[0098] In FIG. 9, the following items are provided: first and second Hadamard sequence multipliers **600** and **700** for respectively having a predetermined number of channels allocated and outputting α_{n1}W_{M,n1}X_{n1 }which is obtained by multiplying the data X_{n1 }of each channel by the gain α_{n1 }and the orthogonal Hadamard sequence W_{M,n1}; α_{n2}W_{M,n2}X_{n2}, which is obtained by multiplying the data X_{n2 }of the gain α_{n2 }and the orthogonal Hadamard sequence W_{M,n2}; a first adder **810** for outputting

[0099]

[0100] which is obtained by summing the output signals from the first Hadamard sequence multiplier **600**; a second adder **820** for outputting

[0101]

[0102] which is obtained by summing the output signals from the second Hadamard sequence multiplier **700**; a complex multiplier **900** for receiving the output signal from the first adder **810** and the output signal from the second adder **820** in the complex form of

[0103]

[0104] and complex multiplying the received signal by W_{M,I}+jPW_{M,Q}, which consist of the orthogonal Hadamard code W_{M,I}, and the permuted orthogonal Hadamard code PW_{M,Q}, wherein W_{M,Q }and a predetermined sequence P are multiplied; a spreading unit **300** for multiplying the output signal from the complex multiplier **900** by a spreading code; a filter **400** for filtering the output signal from the spreading unit **300**; and a modulator **500** for modulating the output signal from the filter **400** by multiplying the modulation carrier wave, summing the in-phase signal and the quadrature phase signal and outputting a real part of the modulated signal.

[0105] Additionally, in FIG. 9 the construction of the spreading unit **300**, the filter **400** and the modulator **500** is the same as the embodiment of FIG. 4. However, in FIG. 9, the multiplication of the complex orthogonal Hadamard sequence is separated from the complex multiplier **100** through **100** *n *and implemented in the rear portion of the summing unit. The multiplication of each channel by the complex orthogonal Hadamard sequence is not implemented, and the summed signals of two groups are multiplied by the complex type orthogonal Hadamard sequence.

[0106] In the first orthogonal Hadamard sequence multiplier **600** α_{11}W_{M,11}X_{11}, is obtained through multiplier **610**, **611**, **620**, **621**, **630**, **631**, **640** and **641** by multiplying first data X_{11 }of the first group by the orthogonal Hadamard sequence W_{M,11 }and the gain α_{11 }. Respectively, α_{21}W_{M,21}X_{21 }is obtained by multiplying the second data X_{21 }of the first group by orthogonal Hadamard sequence W_{M,21 }and the gain α_{21. }Additionally α_{n1}W_{M,n1}X_{n1 }is obtained by multiplying the n-th data X_{n1 }of the first group by orthogonal Hadamard sequence WM,nl and the gain α_{n1. }

[0107] The first adder **810** sums α_{n1}W_{M,n1}X_{n1 }of each channel to output

[0108]

[0109] In the second orthogonal Hadamard sequence multiplier **700**, α_{12}W_{M,12}X_{12 }is obtained through multiplier **720**, **721**, **730**, **731**, **740** and **741** by multiplying the first data X_{12 }of the second group by the orthogonal Hadamard sequence W_{M,12 }and the gain α_{12 }Respectively, α_{22}W_{M,22}X_{22 }is obtained by multiplying the the second data X_{22 }of the second group by the Hadamard sequence W_{M,22 }and the gain α_{22. }Additionally, α_{n2}W_{M,n2}X_{n2 }is obtained by multiplying the n-th data X_{n2 }of the second group by the orthogonal sequence W_{M,n2 }and the gain α_{n2. }

[0110] The second adder **820** sums α_{n2}W_{M,n2}X_{n2 }of each channel to output

[0111]

[0112] The signal outputted from the first adder **810** forms an in-phase data and the signal outputted from the second adder **820** forms quadrature phase data. In addition, the complex multiplier **900** receives the output signals in the complex form from the first and second adder **810** and **820** and multiplies the complex output signals

[0113]

[0114] from the first and second adders **810** and **820** by a complex signal of W_{M,I}+jPW_{M,Q }that is comprised of an orthogonal Hadamard code W_{M,I }and PW_{M,Q}, which results from the multiplication of the orthogonal Hadamard code W_{M,Q }by the sequence P. P is a predetermined sequence, spreading code or integer configured so that two consecutive sequences have identical values. Accordingly, the complex output signals from the first and second adders **810** and **820** are complex-multiplied by the complex signals of W_{M,I}+jPW_{M,Q }by the complex multiplier **900**.

[0115] The spreading unit **300** multiplies the output signal from the complex multiplier **900** by the spreading code SCI and spreads the same. Thus, the spread signals are then filtered by the pulse shaping filters **410** and **420**. The modulation carrier waves of cos(2πf_{c}t) and sin(2πf_{c}t) are multiplied by the modulation multipliers **510** and **520** thereby outputting s(t). In the following equation is obtained.

[0116]

[0117] where K represents an integer greater than or equal to 1.

[0118]FIG. 10 illustrates an embodiment where two channel data are complex-multiplied. Channel data X_{11}, is allocated to the first orthogonal Hadamard sequence multiplier **600** and another channel data X_{12 }is allocated to the second orthogonal Hadamard sequence multiplier **700**.

[0119] As shown, the orthogonal Hadamard sequence multiplier includes the following:

[0120] a first multiplier **610**; a second multiplier **611**; a third multiplier **710**; and a fourth multiplier **711**.

[0121] The complex multiplier **900** includes the following: fifth and sixth multipliers **901** and **902**; seventh and eighth multipliers **903** and **904** multiplier **711** by the permutated; a first adder **905**; and a second adder **906**.

[0122] Therefore, the first and second multipliers **610** and **611** multiply the data X_{11 }by the orthogonal Hadamard sequence W_{M,11 }and the gain all thereby outputting α_{11}W_{M,11}X_{11}(=a). In addition, the third and fourth multipliers **710** and **711** multiply the data X_{12 }by the orthogonal Hadamard sequence W_{M,12 }and the gain α_{12 }thereby outputting α_{12}W_{M,12}X_{12}(=b). The fifth and sixth multipliers **901** and **902** multiply α_{11}W_{M,11}X_{11}(=a) and α_{12}W_{M,12}X_{12}(=b) by the orthogonal Hadamard sequence W_{M,I(=c) thereby generating α} _{11}W_{M,11}X_{11}W_{M,I}(=ac) and α_{12}W_{M,12}X_{12}W_{M,I(=bc). The seventh and eighth multipliers 903 and 904 multiply α} _{11}W_{M,11}X_{11}(=a) and α_{12}W_{M,12}X_{12}(=b) by the permuted orthogonal Hadamard sequence PW_{M,Q }thereby generating α_{11}W_{M,11}X_{11}PW_{M,Q}(=ad) and α_{12}W_{M,12}(=bd).

[0123] The first adder **905** outputs (α_{11}W_{M,11}X_{11}W_{M,I})-(α_{12}W_{M,12}X_{12}PW_{M,Q}) (=ac-bd). That is, α_{12}W_{M,12}X_{12}PW_{M,Q}(bd) is subtracted from α_{11}W_{M,11}X_{11}W_{M,I}(=ac). The second adder **906** generates (α_{11}W_{M,11}X_{11}PW_{M,Q})+(α_{12}W_{M,12}X_{12}W_{M,I})(=ad+bc). That is, (α_{11}W_{M,11}X_{11}PW_{M,Q})(=ad) is summed by (α_{12}W_{M,12}X_{12}W_{M,I}) (bc).

[0124]FIG. 10 illustrates the complex multiplier **900** shown in FIG. 9. For example, α_{11}W_{M,11}X_{11 }is “a”, α_{12}W_{M,12}X_{12 }is “b”, the orthogonal Hadamard sequence W_{M,I }is “c”, and the permuted orthogonal Hadamard sequence PW_{M,Q }is “d”. Since (a+jb)(c+jd)=ac−bd+j(bc+ad), the signal from the complex multiplier **900** consists of the in-phase information ac-bd and the quadrature phase information bc+ad.

[0125] The in-phase and quadrature phase information is spread by the spreading unit **300** based on the spreading code (for example, PN code). In addition, the I channel signal, which is the in-phase information, and the Q channel signal, which is the quadrature phase information signal, are filtered by the first and second pulse shaping filters **410** and **420**. The first and second multipliers **510** and **520** multiply the output signals from the first and second pulse shaping filters **410** and **420** by cos(2πf_{c}t) and sin(2πf_{c}t). The output signals from the multipliers **510** and **520** are summed by the adder **530** which outputs S(t).

[0126] The embodiment as shown in FIG. 9 is identical to FIG. 4 instead of orthogonal Hadamard sequence, Walsh code or other orthogonal code may be used. In addition, in the orthogonal Hadamard sequence of each channel, the sequence vector of the k-th column or row is set to W_{k−l in the M×M Hadamard matrix. Preferably, α} _{n1}W_{0}X_{n1}+jα_{n2}W_{2p}X_{n2 }and W_{0}+jPW_{1 }are complex-multiplied based on W_{M,n1}=W_{0}, W_{M,n2}=W_{2p }(where p represents a predetermined number in a range from 0 to (M/2)−1, and W_{M,1}=W_{0}, W_{M,Q}=W_{1}. The orthogonal Hadamard sequence is allocated to each channel based on the above-described operation, and if other channels remain which are not allocated the orthogonal Hadamard sequence by the above-described operation then any row or column vector from the Hadamard matrix can be selected.

[0127]FIG. 11 illustrates an embodiment of a permuted orthogonal complex spreading apparatus with two input channels. In this case, the data of two channels, namely, the pilot channel and the data of traffic channels are multiplied by the gain and orthogonal Hadamard sequence. The two channel signals are then inputted into the complex multiplier **900** in the complex form and the orthogonal Hadamard sequence of the complex form is multiplied by the complex multiplier **900**.

[0128]FIG. 12 illustrates an embodiment of a permuted orthogonal complex spreading apparatus with three input channels. The pilot channel and signaling channel are allocated to the first orthogonal Hadamard sequence multiplier **700** and the traffic channel is allocated to the second orthogonal Hadamard sequence multiplier **700**.

[0129]FIG. 13A illustrates an embodiment of a permuted orthogonal complex spreading apparatus with four input channels. In FIG. 13B, the system may be constructed so that the input data (traffic **1** and traffic **2**) have identical gains (α_{31}=α_{12}).

[0130]FIG. 14A and 14B illustrate an embodiment of a permuted orthogonal complex spreading apparatus with five input channels.

[0131] In FIG. 14B, when the data (Traffic) is separated into two channel data (Traffic **1**) and (Traffic **2**) and then is inputted, the gains adapted to each channel are identical (α**31**=α**12** ).

[0132]FIG. 15A is a phase trajectory view of an OCQPSK, according to the present invention. FIG. 15B is a phase trajectory view of a POCQPSK, according to the present invention. FIG. 15C is a phase trajectory view of a complex spreading method, according to PN complex spreading method of the prior art.

[0133] The shapes of the trajectories around the zero point are different when comparing FIGS. 15A, 15B and **15**C. This difference indicates the difference between the three methods.

[0134]FIG. 7 illustrates a statistical distribution of a peak power-to-average power ratio of the CDMA ONE method compared to the OCQPSK and POSQPSK methods.

[0135] In order to provide the identical condition the following has to occur: power level of the signal channel is controlled to be the same as the power level of the communication channel; power level of the pilot channel is controlled to be lower than the power level of the communication channel by 4dB.

[0136] In the case of the POCQPSK, in the first block **600** of FIG. 9, W_{M,11}=W_{0}, and W_{M,21}=W_{2 }are implemented and in the second block **700** W_{M,12}=W_{4, }and W_{M,I}=W_{0 }and W_{M,Q}=W_{1 }are implemented. For the value of P, the spreading code is used so that two consecutive sequences have an identical value.

[0137] For example, the probability that the instantaneous power exceeds the average power value (0dB) by 4dB is 0.1% based on POCQPSK, and the complex spreading method is 2%. Therefore, in view of the power efficiency, the method in accordance with the present invention, is a new modulation method having excellent characteristics.

[0138] As described above, in the OCQPSK in accordance with the present invention, the first data and the second data are multiplied by the gain and orthogonal code, and the resultant values are complex-summned, and the complex summed value is complex-multiplied by a complex type orthogonal code. A method is utilized where the information of the multichannel of the identical structure is summed and then spread. Therefore, this method statistically reduces the peak power-to-average power ratio to the desired range.

[0139] Additionally, in the POCQPSK the data of the first block and the data of the second block are multiplied by the gain and the orthogonal code, respectively, and the permuted orthogonal spreading code of the complex type is complex-multiplied and then spread. Therefore, this method statistically reduces the peak power-to-average power ratio to the desired range. Utilizing the combined orthogonal Hadamard sequence, it is possible to decrease the phase dependency based in multichannel and multi-user interference.

[0140] Although, the preferred embodiments of the present invention have been disclosed for illustrative purposes those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as recited in the accompanying claims.

Referenced by

Citing Patent | Filing date | Publication date | Applicant | Title |
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US6745050 * | Feb 14, 2001 | Jun 1, 2004 | Massachusetts Institute Of Technology | Multichannel multiuser detection |

US6956891 * | Oct 5, 2001 | Oct 18, 2005 | Go-Cdma Limited | Method and apparatus for non-linear code-division multiple access technology |

US7139305 * | Aug 2, 2002 | Nov 21, 2006 | Infineon Technologies Ag | Configurable terminal engine |

US7433385 * | Sep 20, 2000 | Oct 7, 2008 | Nokia Corporation | Code division multiple access communication |

US8693526 * | Feb 16, 2012 | Apr 8, 2014 | Chester Wildey | Unipolar spread spectrum modulation for low computation and power cost signal multiplexing with application to fNIRS measurments |

US20130215934 * | Feb 16, 2012 | Aug 22, 2013 | Chester Roy Wildey | Unipolar spread spectrum modulation for low computation and power cost signal multiplexing with application to fnirs measurments |

Classifications

U.S. Classification | 375/144, 375/146, 375/148 |

International Classification | H04J13/10, H04B7/26, H04J13/00, H04J11/00 |

Cooperative Classification | H04J13/0048, H04J13/102, H04J2013/0037, H04B1/7097 |

European Classification | H04J13/10A, H04J13/00B7B |

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