CN100386976C - Power controlling method for frequency-selective single carrier partitional transmitting system - Google Patents
Power controlling method for frequency-selective single carrier partitional transmitting system Download PDFInfo
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Abstract
The present invention relates to a power controlling method in a frequency-selective single carrier partitional transmitting system, which comprises the following steps: (1) after a receiving part and a sending part establish communication, back corresponding desired equalization signal-to-noise ratio, namely the ratio of back equalization signal power and noise power, is calculated by a receiving end according to modulation modes and system performance required to be achieved, namely error rate; (2) the receiving end selects available sub-channels according to obtained channel state information, when the back equalization signal-to-noise ratio is guaranteed, a desired reception signal-to-noise ratio is calculated; then signal power desired by a sending end is calculated through the reception signal-to-noise ratio and link subsidence, the power value of sending signals is called power control information PT which is transmitted to the sending end through feedback channels; (3) the sending end regulates sending power according to the received power control information and sub-channel label information and send sends signals. The present invention changes the power of the sending signals according to good or bad channel states, and further improves power utilization.
Description
(I) technical field
The invention relates to a broadband digital communication transmission method. Belongs to the technical field of broadband wireless communication.
(II) background of the invention
Communication technology has been developed over the last decades, particularly the nineties of the twentieth century, with profound effects on the development of people's daily lives and national economy. In the future, communication technologies are developing towards high-speed broadband, so that many broadband digital transmission technologies are receiving wide attention, and Orthogonal Frequency Division Multiplexing (OFDM) and Single Carrier with frequency Domain Equalization (SC-FDE) are two broadband digital transmission technologies that are regarded by people, and both of them belong to block transmission technologies, while OFDM is far more concerned than SC-FDE at present, and become support technologies in various standards, for example: IEEE802.11a in a Wireless Local Area Network (WLAN), HiperLAN/2 in European Telecommunications Standardization Institute (ETSI), IEEE802.16 in a Wireless Metropolitan Area Network (WMAN); various high-speed Digital Subscriber lines (xDSL) in wired data transmission are standards based on OFDM technology. SC-FDE is not adopted by these standards, but is proposed as a physical layer transmission technique in IEEE802.16 in combination with OFDM.
OFDM is a multi-carrier transmission technique that uses N subcarriers to divide the entire wideband channel into N parallel mutually orthogonal narrowband subchannels. OFDM systems have a number of compelling advantages: 1. very high spectral efficiency; 2. the realization is simpler; 3. the anti-multipath interference capability and the anti-fading capability are strong; 4. channel state information (i.e., adaptive OFDM techniques) may be utilized to further improve spectral efficiency, etc.
The adaptive OFDM technology can change the signal transmission power along with the change of the channel condition by utilizing the channel state information, namely, the total transmission power is minimized under the conditions that the transmission code rate is constant and a certain bit error rate requirement is met, thereby realizing power control, reducing the transmission power as much as possible and improving the power utilization rate.
It is these advantages that make OFDM a hot research topic in the last decade and is considered as a supporting technology for future communications, especially broadband wireless communications. However, the OFDM system has many disadvantages, especially its peak-to-Average Power Ratio (PAPR: peak Average Power Ratio) is too large, which limits its practical pace, and the existing SC-FDE has all the advantages of OFDM except the 4 th point, and has no PAPR problem of OFDM, and the performance and efficiency are basically equivalent to that of OFDM. The SC-FDE system is developed on the basis of researching OFDM, the SC-FDE system adopts block transmission like OFDM, and adopts CP (if a Zero Padding (ZP) mode is adopted, the trailing of each frame is superposed on the front of the frame, the effect is the same as that of CP), so that the linear convolution of the signal and the impulse response of the channel can be converted into cyclic convolution, and the interframe interference caused by multipath is eliminated. And the simple frequency domain equalization technology is adopted at the receiving end to eliminate the inter-symbol interference, for example: zero Forcing (ZF) equalization and Minimum Mean Square Error (MMSE) equalization.
Compared with OFDM, the SC-FDE system has no PAPR problem. The PAPR problem is a problem that the OFDM system itself is difficult to solve in a low-cost manner (spectrum efficiency and power efficiency). SC-FDE technology is therefore currently receiving increasing attention. The mathematical model of the conventional SC-FDE system is briefly described below.
In the SC-FDE system, a frame of time domain signal transmitted by a transmitting end is s (N), (N is 0, 1, …, N-1), an impulse response of a channel through a time-varying multipath channel is h (N), (N is 0, 1, … L-1), interference of Additive White Gaussian Noise (AWGN) is received during signal transmission, the Noise is w (N), (N is 0, 1, …, N-1), and after the CP is removed, a received time domain signal r (N) is:
wherein,
representing a circular convolution operation.
At the receiving end, the signal is transformed into the frequency domain by Discrete Fourier Transform (DFT), and the obtained frequency domain signal is the frequency domain signal according to the time domain convolution theorem of DFT
R(k)＝S(k)·H(k)+W(k)，(k＝0，1，…，N-1) (2)
Where, r (k), s (k), h (k), w (k) are r (N), s (N), h (N), w (N) are frequency domain symbols of N-point DFT, and h (k), (k ═ 0, 1, …, N-1) are frequency domain responses of the channel. The frequency domain signal after zero forcing equalization is
And finally, performing Inverse Discrete Fourier Transform (IDFT) on the signal, converting the signal back to a time domain for judgment, and obtaining the data transmitted by the transmitting end.
As can be seen from equation (3), the finally obtained signal has an error compared with the transmitted real signal, the error is caused by noise, especially, the noise is amplified excessively when the channel has a deep attenuation point, and in addition, the signal is distorted when MMSE equalization is used. These problems are alleviated if channel state information is utilized in the SC-FDE system. Therefore, the applicant proposes a frequency-selective single-carrier block transmission method (applied national invention patent, patent application number: 200410036439.6), which overcomes the disadvantage that the traditional SC-FDE system cannot utilize the channel state information, and the new SC-FDE system has higher system performance and efficiency.
The method for realizing the single carrier block transmission in the frequency selection mode comprises the following steps:
first step, finding out available sub-channel, marking whether the channel is available, then sending the sub-channel marking information to the sending end through reverse channel
The receiving end selects M (M is less than or equal to N) usable sub-channels from N sub-channels according to the estimated channel state information H (k), (k is 0, 1, …, N-1) and according to the amplitude gain, and the labels of the M usable sub-channels are ki(i ═ 0, 1, …, M-1), and the remaining subchannels are disabled, and 1-bit information, i.e., "0" or "1", is used to mark whether each subchannel is available or unavailable, which is the subchannel marking information required by the transmitting end, if the receiving end performs N-point DFT, i.e., N subchannels are in total, the subchannel marking information fed back to the transmitting end has N bits, and then the N-bit information is sent back to the transmitting end through the reverse channel.
Second, the signal spectrum is changed according to the subchannel flag information
After receiving the subchannel flag information sent back by the receiving end, the transmitting end can use M available subchannels to transmit signals, so that for a frame of M SC-FDE symbols s (n), (n ═ 0, 1, …, M-1), M-point DFT is performed to transform to the frequency domain:
obtaining the frequency domain signal of M points, using the k-th selectedi(i-0, 1, …, M-1) available subchannels H (k)i) (i-0, 1, …, M-1) the ith frequency domain signal S (i), (i-0, 1, …, M-1) is transmitted, that is, the frequency domain signal to be transmitted is placed at the signal spectrum point corresponding to the available sub-channel, the signal spectrum point corresponding to the forbidden sub-channel is set to zero, and some non-information data can be filled, so as to obtain a new frame of frequency domain signal S '(k), (k-0, 1, …, N-1), point S' (k), (k-0, 1, …, N-1), and the point S (i) is transmittedThe number is N:
then, for S' (k), (k ═ 0, 1, …, N-1), an N-point IDFT is made:
and changing the time domain signal into a time domain signal, wherein the IDFT point number is more than N during oversampling, the high frequency part is set to zero, and the time domain signal is modulated and sent out after being subjected to D/A.
And thirdly, selecting the signals transmitted on the available sub-channels, then balancing the selected signals, converting the signals back to a time domain for judgment, and finally obtaining the transmitted data.
The receiving end receives the signal, and the time domain discrete signal after the CP is removed is:
DFT of N points is carried out:
and:
R′(k)＝S′(k)H(k)+W(k)，(k＝0，1，…，N-1) (9)
this makes it possible to select the signals R' (k) on the M available subchannels on the basis of the subchannel label informationi) (i-0, 1, …, M-1), and then using the available subchannel parameters H (k) in the estimated channel state informationi) (i-0, 1, …, M-1), equalizing the selected signal; one of three equalization modes can be selected:
1. zero-forcing equalization is carried out on the data,
2. the minimum mean square error is balanced, and the minimum mean square error is balanced,
3. hybrid equalization, i.e. one part of the subchannels is equalized with zero-forcing and the other part of the subchannels is equalized with minimum mean square error;
zero forcing equalization is taken as an example for introduction:
order to
IDFT to which M points are made:
the decision on this set of data can recover the original data.
Disclosure of the invention
The single carrier block transmission method of the frequency selection mode utilizes the channel state information and can avoid deep attenuation points for frequency selective fading channels, thereby obviously improving the performance of the system. Communication systems generally have certain requirements on error code performance, and the parameter determining the error code performance of the system is an available equalized signal-to-noise ratio, i.e., a ratio of equalized signal power to noise power. Therefore, the invention provides a power control method of a single carrier block transmission system based on a frequency selection mode, which reduces the power of a transmitted signal as much as possible and can effectively save the transmitted power under the condition of ensuring that the signal-to-noise ratio after equalization meets the requirement of the error code performance of the system.
The power control method comprises the following steps:
(1) after the two parties establish communication, the receiving end calculates the corresponding required signal-to-noise ratio after equalization, namely signal power and noise after equalization according to the modulation mode and the system performance, namely the bit error rate, which is achieved by the requirementThe ratio of the acoustic powers, denoted as SNReq。
(2) The receiving end selects an available sub-channel according to the obtained channel state information, and the signal-to-noise ratio is ensured to be SNR after equalizationeqCalculating required receiving signal-to-noise ratio, calculating signal power required by the transmitting end through the receiving signal-to-noise ratio and link attenuation, and calling the signal power required by the transmitting end as power control information PTAnd is transmitted to the transmitting end through a feedback channel.
(3) And the sending end adjusts the sending power and sends signals according to the received power control information and the subchannel marking information.
The above steps are explained in detail below:
step (1), the receiving end calculates the required balanced signal-to-noise ratio according to the modulation mode and the system performance required
After analysis, the SC-FDE system has strong anti-jamming capability, when the channel estimation error and the synchronization error can be ignored, after the receiving end is equalized, the multipath channel is equivalent to a Gaussian channel, which is equivalent to that the whole system is only interfered by white Gaussian noise, and the Gaussian channel adopts different modulation modes to reach the signal-to-noise ratio required by the required bit error rate, namely the signal-to-noise ratio SNR required by the system after equalizationeqThe calculation method can be found in general textbooks such as "digital communications" (fourth edition) (digital communications 4) published by The McGraw-Hill company, inc, by john.g. proakisthEdition) page 254-; when considering the channel estimation error and the synchronization error, the error range and the loss signal-to-noise ratio of the actual system can be estimated by measuring, the calculation method of the loss signal-to-noise ratio can be referred to the relevant literature, and the SNR is increased appropriatelyeqTo offset the signal-to-noise ratio lost by these errors.
Step (2), the receiving end calculates the signal power needed by the transmitting end according to the channel state information, the needed signal-to-noise ratio after equalization and the link attenuation to form power control information
The equalized signal-to-noise ratio determines the system error rate, and the equalized signal-to-noise ratio is determined by the received signal-to-noise ratio and the equalization mode. The signal power and the noise power after equalization are different due to different equalization modes, the required receiving signal-to-noise ratio is different, and the signal power required by the transmitting end is different due to the fact that the receiving signal-to-noise ratio and the link attenuation determine the signal power required by the transmitting end; the method for measuring and calculating the received signal-to-noise ratio can refer to relevant documents, and the following describes a method for calculating the signal power required by the originating terminal by taking zero forcing equalization as an example:
assuming white Gaussian noise bilateral power spectral density
(W/Hz), the receiving end selects M (M is less than or equal to N) available subchannels from large to small according to the amplitude gain according to the channel state information h (k), (k is 0, 1, …, N-1) obtained by channel estimation, and the subscript of the selected M subchannels is defined as ki(i-0, 1, …, M-1), and the channel gain of these subchannels is | H (k)i) I ═ 0, 1, …, M-1. The total noise power per frame after equalization is, in watts:
the required post-equalization signal-to-noise ratio is known as SNReqThen the received signal power required per frame is, in watts:
considering the link attenuation, if the link attenuation is L, the signal power required by the transmitting end is, in watts:
and forming power control information by the power value through a feedback channel and transmitting the power control information to the transmitting end.
Step (3), the sending end adjusts the sending power according to the received power control information and the sub-channel mark information, selects the available sub-channel and sends the signal
The sending end makes the total sending power equal to the signal power required by the feedback sending end according to the received power control information, and sends a signal; in practical application, the sending power of the system should be slightly larger than the signal power required by the feedback sending end, and a certain margin is left to ensure that the signal-to-noise ratio control is relatively stable and meets the system requirements.
The single carrier block transmission system based on the frequency selection mode controls the signal-to-noise ratio to be a fixed value after the receiving end is controlled to be balanced by changing the signal power required by the transmitting end according to the obtained channel state information, thereby controlling the signal power required by the transmitting end. Therefore, the signal power required by the transmitting end is changed according to the channel state, and the power utilization rate is further improved.
(IV) description of the drawings
Fig. 1 is a block diagram of a system implementing the proposed method of the invention.
FIG. 2 is a diagram of selecting 208 available sub-channels by adopting a 16QAM modulation method, and controlling the bit error rate to be 10-4The received signal-to-noise ratio curve of time.
FIG. 3 is a diagram of selecting 208 available sub-channels by using 16QAM modulation method to control the bit error rate to 10-4The resulting bit error rate is simulated.
In the figure: 1. the system comprises a source module, 2, a symbol mapping module, 3, an FFT module (M point), 4, a signal spectrum transformation module, 5, an IFFT module (N point), 6, a power control module, 7, a Cyclic Prefix (CP) adding module, 8, a D/A module, 9, an intermediate frequency and radio frequency modulation module, 10, a channel, 11, a radio frequency and intermediate frequency demodulation module, 12, an A/D module, 13, a CP removing module, 14, a gain control module, 15, an FFT module (N point), 16, a signal spectrum inverse transformation module, 17, an equalization module, 18, an IFFT module (M point), 19, a judgment module, 20, a channel estimation and signal power calculation module, 21, a synchronization module, 22, a reverse channel, a signal power calculation module, a
(V) detailed description of the preferred embodiments
Fig. 1 shows a block diagram of a system for implementing the method of the present invention, and the functions of the modules are as follows:
the information source module 1: data to be transmitted is generated.
The symbol mapping module 2: and when the modulation mode selects QAM or MPSK, mapping the data generated by the information source to the corresponding points of the constellation diagram.
M-point FFT module 3: and transforming the M mapped signals of each frame to a frequency domain to obtain M-point frequency domain signals of the signals.
The signal spectrum transformation module 4: according to the sub-channel marking information sent back by the receiving end through the reverse channel 22, the M-point frequency domain signal output by the module 3 is placed on the corresponding spectrum points of the M available sub-channels, and the corresponding spectrum points of the forbidden sub-channels are set to zero or non-information data is filled, so that a frame of new SC-FDE frequency domain signal with N points is obtained. This module needs to be programmed according to the method described in the invention patent mentioned in the background of the invention (patent application serial No. 200410036439.6), and is implemented by a general digital signal processing chip.
N-point IFFT module 5: and transforming the newly obtained frequency domain signal to the time domain.
The power control module 6: the transmit signal power is adjusted based on the received power control information.
And a CP adding module 7: and adding a cyclic prefix to each frame of obtained data.
D/A module 8: the digital signal is converted into an analog signal.
Intermediate frequency and radio frequency modulation module 9: if the system is used in a wireless environment, radio frequency modulation of the signal is required to transmit to the antenna. Sometimes, the signal needs to be modulated to an intermediate frequency for intermediate frequency amplification, then radio frequency modulation, and finally the modulated signal is sent to an antenna for transmission. If the system is used in a wired environment (e.g., xDSL), no rf modulation is required, no antenna is required to transmit the signal, and the signal spectrum is shifted outside the voice channel band to ensure that data is transmitted without affecting voice transmission.
Channel 10: a wired channel or a wireless channel that transmits signals.
The synchronization module 21: various synchronous data needed by the system are obtained through a parameter estimation method (such as blind estimation and auxiliary data-based estimation). The synchronization module sends the frequency synchronization data to the radio frequency and intermediate frequency demodulation module 11; sending the sampling rate synchronization data to the analog-to-digital conversion module 12; the timing synchronization data is sent to the de-CP module 13.
Radio frequency and intermediate frequency demodulation module 11: in a wireless environment, the spectrum of a signal received by a receiving antenna is shifted from a radio frequency or an intermediate frequency to a low frequency. Frequency offset caused during signal transmission needs to be corrected by frequency synchronization data before demodulation.
The A/D module 12: the demodulated analog signal is converted into a digital signal. The analog signal needs to be sampled by the a/D, and the crystal oscillator providing the clock signal needs to have the same frequency as the crystal oscillator of the D/a module of the transmitter, otherwise, a sampling rate error may result. The sampling rate synchronization is performed before the a/D.
The CP removing module 13: the cyclic prefix is removed. There is a problem in determining when a frame of data starts, and therefore timing synchronization is required before the CP is removed.
The gain control module 14: and according to the power control information, eliminating the influence of power control on the signal constellation points.
N-point FFT module 15: the CP-removed signal is transformed into the frequency domain.
Channel estimation and transmission signal power calculation module 20: similar to synchronization, CSI is also obtained by parameter estimation, typically blind channel estimation and auxiliary data based channel estimation. After estimating the CSI, selecting available sub-channels, and sending the parameters of the available sub-channels to the equalization module 17; meanwhile, according to whether the channel is available, marking with 1 bit information (0 or 1) to form sub-channel marking information, sending the sub-channel marking information to the signal spectrum inverse transformation module 16 and the reverse channel 22 at the same time, and sending the sub-channel marking information back to the signal spectrum transformation module 4 of the sending end through the reverse channel; the required transmission signal power is calculated according to the equalized signal-to-noise ratio required for reaching different bit error rates, transmitted to the gain control module 14 and the reverse channel 22, and transmitted back to the power control module 6 of the transmitting end through the reverse channel. The power control portion of the module needs to be programmed according to the method described in the present invention and is implemented by a general digital signal processing chip.
The signal spectrum inverse transformation module 16: according to the subchannel flag information sent by the channel estimation and transmission signal power calculation module 20, M-point frequency domain signals carried by available subchannels in the received signal are found out. This module needs to be programmed according to the method described in the invention patent mentioned in the background of the invention (patent application No. 200410036439.6), and is implemented by a general-purpose digital signal processing chip.
The equalization module 17: the signal selected by the inverse signal spectrum transform module 16 is equalized by the available sub-channel parameters from the channel estimation and transmit signal power calculation module 20. The equalization mode can select one of the following three equalization modes: zero-forcing equalization, minimum mean square error equalization, hybrid equalization (i.e., one portion of subchannels equalized with zero-forcing and another portion of subchannels equalized with minimum mean square error).
M-point IFFT module 18: and transforming the M frequency domain signals of the equalized signals to a time domain.
The decision module 19: and finishing the judgment of the time domain signal according to the constellation diagram.
Reverse channel 22: and sending the sub-channel mark information and the power control information back to the sending end.
When the channel estimation error and the synchronization error can be ignored, after the receiving end is equalized, the multipath channel is equivalent to a Gaussian channel, which is equivalent to that the whole system is only interfered by white Gaussian noise, and the signal-to-noise ratio required by the required bit error rate is achieved in the Gaussian channel by adopting different modulation modes, namely the signal-to-noise ratio SNR required by the system after equalizationeq(ii) a Calculation of The bit error rate in The gaussian channel is described in john.g. proakis, Digital Communications, fourth edition (Digital Communications 4) published by McGraw-Hill company, incthEdition) page 278.
Simulation parameters of this embodiment:
simulation environment: matlab7.0
Total number of subchannels: 256 of N
Number of available subchannels, i.e. number of SC-FDE data symbols per frame: and M is 208.
CP Length: 32
Symbol mapping: 16QAM
The controlled error rate is as follows: 10-4
Link attenuation: l-1 (i.e. 0dB, link attenuation not considered here)
Synchronization and channel estimation: ideal estimation, i.e. without error between synchronization parameters and channel estimation results
The technical effect of the present invention can be more clearly illustrated without considering the link attenuation and synchronization parameters and the channel estimation error.
Fig. 2 and 3 show the received SNR curve and the controlled ber case for this embodiment of the present invention in 100 channel samples taken from the SUI-5 channel (one of the test channels proposed in the IEEE802.16 standard), where the SNR of fig. 2 is in dB. It can be seen from the simulation results that the maximum and average received snr values differ by about 3.1dB when the 100 different channel samples are passed (the horizontal line around the ordinate 18.65dB in fig. 2 represents the average received snr). If no power control method is adopted, the system often designs the transmission signal power according to the worst channel condition to ensure stable error code performance. This shows that if the system employs the power control method, it can save power by a larger amount than if the method is not employed, and the power control method of the present invention can save about 3.1dB of transmission power under the simulation conditions in this embodiment. And it can be seen from fig. 3 that this embodiment can stabilize the bit error rate control relatively.
To avoid confusion, some of the terms mentioned in this specification are to be interpreted as follows:
1. signal-to-noise ratio after equalization: the ratio of signal power to noise power after equalization.
2. Symbol: refers to data in which information bits are modulation mapped (also referred to as symbol mapped). Typically a complex number where the real and imaginary parts are integers.
3. A frame signal: for OFDM, a frame signal refers to N symbols that are IFFT-transformed at the transmitting end and N symbols that are FFT-transformed after CP is removed at the receiving end. For SC-FDE, a frame of signal refers to N information symbols between two adjacent CPs at the transmitting end, and refers to N symbols that are FFT-transformed after the CPs are removed at the receiving end. For the SC-FDE system realized by the method provided by the invention, a frame of signal refers to M symbols for FFT transformation at a transmitting end and refers to M symbols for IFFT transformation after equalization at a receiving end.
4. Sub-channel: for OFDM, SC-FDE baseband signals, a subchannel refers to a frequency point after FFT at the receiving end. For a radio frequency channel, a subchannel refers to a segment of the frequency spectrum of the radio frequency channel.
Claims (3)
1. A power control method in a frequency-selective single carrier block transmission system is characterized in that: the power control method comprises the following steps:
(1) after the two parties establish communication, the receiving end calculates the corresponding required signal-to-noise ratio after equalization, namely the ratio of the signal power and the noise power after equalization, and records the ratio as SNR (signal to noise ratio) according to the modulation mode and the system performance, namely the bit error rate, which is achieved by the requirementeq；
(2) The receiving end selects an available sub-channel according to the obtained channel state information, and the signal-to-noise ratio is ensured to be SNR after equalizationeqCalculating required receiving signal-to-noise ratio, calculating signal power required by the transmitting end through the receiving signal-to-noise ratio and link attenuation, and calling the signal power required by the transmitting end as power control information PTThe data is transmitted to a transmitting end through a feedback channel;
(3) and the sending end adjusts the sending power and sends signals according to the received power control information and the subchannel marking information.
2. The method of power control in a frequency selective single carrier block transmission system according to claim 1, characterized by: the step (2) is realized by adopting the following method: the equalized signal-to-noise ratio determines the system bit error rate, the equalized signal-to-noise ratio is determined by a receiving signal-to-noise ratio and an equalizing mode, the equalizing mode is different, the equalized signal power and the equalized noise power are different, the required receiving signal-to-noise ratio is also different, and the receiving signal-to-noise ratio and the link attenuation determine the signal power required by the transmitting end, so the signal power required by the transmitting end is different; the method for calculating the signal power required by the transmitting end comprises the following steps:
assuming white Gaussian noise bilateral power spectral density
The receiving end selects M usable sub-channels from large to small according to amplitude gain according to channel state information H (k) obtained by channel estimation, wherein k is 0, 1, … and N-1, M is less than or equal to N, and subscripts of the selected M sub-channels are set as kiI is 0, 1, …, M-1, and the channel gain of these subchannels is | H (k)i) I is 0, 1, …, M-1, the total noise power per frame after equalization is, in watts:
the required post-equalization signal-to-noise ratio is known as SNReqThen the received signal power required per frame is, in watts:
considering the link attenuation, if the link attenuation is L, the signal power required by the transmitting end is, in watts:
and forming power control information by the power value through a feedback channel and transmitting the power control information to the transmitting end.
3. The method of power control in a frequency selective single carrier block transmission system according to claim 1, characterized by: and (4) the sending end in the step (3) enables the sending total power to be equal to the signal power required by the feedback sending end according to the received power control information, and sends signals.
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| CN101951354A (en) * | 2010-09-01 | 2011-01-19 | 深圳市业通达实业有限公司 | Power line carrier baseband signal modulator-demodulator based on COFDM |
| CN108599864B (en) * | 2018-03-06 | 2024-04-12 | 东南大学 | Incoherent optical communication multiple access system based on broadband filter bank |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1249653A (en) * | 1998-09-18 | 2000-04-05 | 日本电气株式会社 | System and method for control of transmitted power |
| CN1256817A (en) * | 1998-02-19 | 2000-06-14 | 夸尔柯姆股份有限公司 | Forward link power control in cellular system using NT/IO values |
| JP2001244881A (en) * | 2000-01-21 | 2001-09-07 | Lucent Technol Inc | Method and system for dynamic down-link power control of time division multiple access radio system |
| WO2002054619A1 (en) * | 2000-12-28 | 2002-07-11 | Nokia Corporation | Method for performing link adaption using fuzzy control |
| CN1463099A (en) * | 2003-06-18 | 2003-12-24 | 清华大学 | Scheduling method for ensuring service quality of real time operation in OFDM |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1256817A (en) * | 1998-02-19 | 2000-06-14 | 夸尔柯姆股份有限公司 | Forward link power control in cellular system using NT/IO values |
| CN1249653A (en) * | 1998-09-18 | 2000-04-05 | 日本电气株式会社 | System and method for control of transmitted power |
| JP2001244881A (en) * | 2000-01-21 | 2001-09-07 | Lucent Technol Inc | Method and system for dynamic down-link power control of time division multiple access radio system |
| WO2002054619A1 (en) * | 2000-12-28 | 2002-07-11 | Nokia Corporation | Method for performing link adaption using fuzzy control |
| CN1463099A (en) * | 2003-06-18 | 2003-12-24 | 清华大学 | Scheduling method for ensuring service quality of real time operation in OFDM |
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| CN1645762A (en) | 2005-07-27 |
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