Method for adaptive distribution of temporal-frequency resource, adaptive modulation, encoding and power adjustment in communication system

FIELD: radio engineering.

SUBSTANCE: method includes determining required values of energy parameters for each client station, predicting value of parameters, distributing temporal-frequency resource between client stations.

EFFECT: higher efficiency of use of temporal-frequency resource, decreased energy consumption during transmission of data.

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The invention relates to the field of radio engineering, in particular to a method of adaptive allocation of time-frequency resource, adaptive modulation, coding and power control in a communication system, and can be used, for example, in systems of cellular communication of the third generation wireless systems of the third and fourth generations during data transfer.

The main problem in the development of communication systems is to increase efficiency in the use of time-frequency resource allocated to the system. Since the conditions of propagation of signals in communication channels can vary considerably over time, it is necessary to adapt the method for use of time-frequency resource to the changing characteristics of the transmission channel.

Known technical solution according to the published patent application US 2002/0036992 "Method and apparatus for packet size dependent link adaptation for wireless packet" H 04 Q 7/00 [1], which considers the communication system comprising at least one base station and at least one mobile station.

The base station receives the data blocks for transmission over the direct channel to the mobile station.

The base station transmits the request to the mobile station measures the downlink channel quality, such as signal-to-noise in the incoming signal. When this request transmits from the only mobile station, waiting to receive data.

The mobile station performs the measurement of the direct channel and transmits the measurement results to the base station.

The base station receives a response with the results of measurements and determines the mobile station, reception conditions which have better. After that, you assign the type of coding and modulation, as well as a time slot for transmission to the mobile station. For example, the first data being transferred to the mobile station with the best reception conditions, then the next reception conditions, etc.

The base station transmits to the corresponding mobile station a message containing the type of coding and modulation and allocated time slots.

The mobile station receives a message with the form of coding and modulation and allocated time slots and prepares to receive data in accordance with the received message.

The described method has the following main disadvantages.

First, it is not taken into account the amount of data that must be transmitted to the mobile station, and transmission bottlenecks are created adjacent satam system.

Secondly, there is no power adjustment when changing the type of coding and modulation.

Known technical solution according to the patent US 6385462 "Method and system for criterion based adaptive power allocation in a communication system with selective etermination of modulation and coding" H 04 Q 7/20, H 04 B 15/00, H 04 B 1/00, H 04 B 17/00 [2], which considers the communication system including at least one transmitter, for example a base station, and N receivers, such as mobile stations.

The system has the capability to measure on the receivers of the communication quality, such as signal-to-noise ratio and to transmit the measurement result to the transmitter.

The system also has the ability to change the transmission power and the type of coding and modulation taking into account existing constraints on the supported range of the radiation power and supported on a set of coding and modulation.

The transmitter knowing the transmit power, the measurement result of communication quality and the required communication quality, determines the required transmission power, which guarantees the required quality of service. The transmitter assigns the received transmit power subject to the restrictions on the supported range of capacity control.

After that, the transmitter assigns a transmission rate in accordance with the assigned transmit power and the corresponding quality of the connection.

Select the desired communication quality is carried out in accordance with one system criterion or according to a combination of several system criteria.

As a possible system of criteria in the patent stated:

The same quality of communication (and the same speed ne is Adachi) for all mobile stations of the system;

Maximizing the number of mobile stations with non-zero data rate;

The same data transmission speed when maximizing the capacity of the communication system;

Minimizing the difference between the quality of communication of users;

The maximization or minimization of the number of users with a maximum data transfer rate;

Maximizing system capacity;

- Noise reduction.

The main disadvantage of this technical solution is that it does not take into account the quantity of data that needs to deliver a particular mobile stations, and does not provide for adaptive allocation of time-frequency resource between mobile stations and between the forward and reverse channels (in the case of temporary duplex).

Without this optimization the above system of criteria may not be possible. In particular, there may be situations where the same throughput cell can be achieved at a lower average transmit power. Then create unreasonable interference with other satam, and the capacity of the system as a whole will be below practically achievable.

Closest to the technical nature of the decision to the claimed method is the solution described in published patent application US 2002/0183010 "Wireless communication systems with adaptive channelization and link adaptation" H 04 B 17/00 [3].

This technical solution being treated is tsya communication system, including at least one base station and N subscriber stations served by this base station.

The base station transmits the data to the subscriber station via the direct channel and the subscriber stations transmit data to the base station via a reverse channel.

The transmitter of the base station and the transmitter of the subscriber stations have the ability to periodically change the appearance of the coding and modulation data of the individual subscriber stations, as well as reallocate time-frequency resource of the forward and reverse channel system between them. Under the frame understand the throttling interval type of coding and modulation and assignment of time-frequency resource subscriber stations.

The receiver of the base station and the receivers of the subscriber stations when receiving data have the possibility to measure the energy parameters characterizing the quality of reception of data, such as signal-to-noise in the incoming signal.

During data transfer in the forward or in the reverse channel, you must take them to the specified quality, for example with a probability of bit error not exceeding a specified probability.

For each type of coding and modulation known minimum values of energy parameters, ensuring the specified quality.

For a better understanding of the method prototype [3] at the Eden 1.

Figure 1 shows a base station 1, containing at least block 2 encoding and modulation unit 3 demodulation and decoding and block 4 adaptation, and one of the N present in the system subscriber stations served by the base station 1 and the subscriber station 5, containing, as a minimum, unit 6, demodulation and decoding unit 7 measurement of the energy parameter and the block 8 encoding and modulation.

Consider implementing a known method on the example of data transfer in the forward channel from base station 1 to the subscriber station 5.

On the first N inputs of the base station 1 receives N signals containing the data you wish to transfer the N subscriber stations in the generated frame of the downlink channel. These N signals are sent to the first N inputs of block 4 of adaptation.

Unit 4 adaptation signal is generated by the service, contains the type of coding and modulation for each of the N data signals and the description of the plot of time-frequency resource of the formed frame direct channel allocated for data transmission of each of the N subscriber stations.

Under the area of time-frequency resource of the formed frame direct channel see, for example, part of the frame allocated to the subscriber station. Then the area of time-frequency resource block may be described by the magnitude of the displacement in time of the beginning and end of the segment relative to the beginning of the frame is.

From the second output unit 4 adaptation service signal at the second input unit 2 encoding and modulation, and outputs from the first block 4 N signals containing the data to arrive at unit 2 encoding and modulation. Unit 2 coding and modulation in accordance with the received service signal performs coding and modulation of the N signals containing data, and generates a frame in accordance with the areas of time-frequency resource assigned to the N subscriber stations.

Together with the N signals containing the data in the generated transmit frame utility signal containing information about the types of coding and modulation, and on the distribution of time-frequency resource between subscriber stations for the frame following the generated frame directly or through one or more frames.

The formed frame from the output unit 2 is supplied to the first output of the base station 1. With the first base station 1 receives at the first input of subscriber stations 5 and respectively to the inputs of block 6 of the demodulation and decoding unit 7 measurement of the energy parameter.

In block 6 of the demodulation and decoding demodulator and decode the part of the received frame, the selected subscriber stations 5, using the information contained in the message of one of the previous received frames and described the surrounding used in the received frame types of coding and modulation and distribution of time-frequency resource of the received frame between subscriber stations.

Unit 6 demodulation and decoding also demodulates and decodes the plot of the received frame containing service message, which is then used to decode the corresponding frame.

The data contained in the received frame and the intended subscriber station 5, from the output unit 6 receives the first output subscriber stations 5.

In block 7 of measuring energy parameter according to the received frame measured energy parameter characterizing the quality of reception of data, such as signal-to-noise in the incoming signal.

The signal containing the measured energy parameter comes from the output of the unit 7 to the first input unit 8 encoding and modulation. To the second input unit 8 encoding and modulation signal from the second input of the subscriber stations 5, containing data intended for transmission to the base station 1.

Unit 8 encoding and modulation performs coding and modulation signal containing data and a signal containing the measured energy parameter.

The signal after encoding and modulation comes from the output of the unit 8 encoding and modulation on the second output of the subscriber station 5, and with him - to the second input of the base station 1 and respectively to the input unit 3 demodulation and decoding.

Unit 3 demodulation and decoding Khujand who performs demodulation and decoding of the received signal and receives data, with his second output are on the second output of the base station 1 and the measured energy parameter comes from its first output to the second input of block 4 of adaptation.

In unit 4 adaptation compare the measured energy parameter with a known minimum values of the energy parameters for each type of coding and modulation and appoint another form the frame of the downlink channel of each of the N subscriber stations type of coding and modulation, and the area of time-frequency resource so as to maximize the throughput of one of the N subscriber stations or all of the N subscriber stations served by base station 1. Under bandwidth understand, for example, the data transfer rate.

Thus, according to the description mentioned known method of adaptive allocation of time-frequency resource, adaptive modulation, coding and power control in a communication system we can identify the following main features of its implementation:

for each generated frame forward and reverse channels for each subscriber station determines the required values of energy parameters for different types of coding and modulation depending on the required quality;

measured values of the energy parameters in the current frame direct the go and return paths;

transmit to the base station values of the energy parameters measured in the direct channel;

assign the base station to each subscriber station type of coding and modulation, as well as a plot of time-frequency resource in the generated frames forward and reverse channels.

The known method [3] has the following major drawbacks.

First, the method does not allow for adaptive power adjustment simultaneously with the distribution of time-frequency resource and adaptive modulation and coding.

It is possible that the measured value of the energy parameter is above the minimum required values for the first part of the modulation types and coding, but less than the minimum required values for the rest of the second part of the modulation and encoding.

Then, to maximize throughput according to a known method, assign the type of modulation and coding of the first part having a maximum data rate. However, the transmit power will be redundant.

This will lead at least two negative consequences: will unreasonably increased intra-system interference, and would be unreasonably increased energy consumption.

Secondly, is not taken into account the amount of data that must be passed for each subscriber station is in the direct channel and from each subscriber station in the reverse channel. It should be considered, for example, the situation when the data transfer of each subscriber station at the highest possible speed will leave part of the frequency-time resources of the frame free. Since the data rate is defined as the average of the frame, it is possible to transfer the same amount of data per frame at lower transmission speeds and, accordingly, less power. This deficiency leads at least to the same negative consequences as the first drawback.

Thirdly, the achievement of the maximum throughput of a single or all subscriber stations served by one base station, does not always lead to the maximum capacity of the communication system, which is usually understood as averaged over the entire communication system throughput.

This leads to economically inefficient use of the selected communication system of time-frequency resource.

The problem to address with the inventive method, is to increase the efficiency of time-frequency resource of the communication system.

The solution of this problem is due to the fact that in the method of adaptive allocation of time-frequency resource, adaptive modulation, coding and power control in a communication system base station and N subscriber stations, that is, for each subscriber station must in every frame forward and reverse channels to provide the requested amount of data with a given quality, namely, that for each generated frame forward and reverse channels:

for each subscriber station determines the required values of energy parameters for different types of coding and modulation depending on a given quality,

measured values of the energy parameters in the current frame forward and reverse channels

transmit to the base station values of the energy parameters measured in the direct channel,

according to the invention introduce the following sequence of operations:

for each subscriber station determines the required values of energy parameters for different types of coding and modulation depending on a given amount of data needed to transmit the generated frame forward and reverse channels

predict the amount of energy parameters generated by frame forward and reverse channels according to the values of the capacities of the transmission and the measured energy parameters of previous frames

determine the required values of transmission capacity for different types of coding and modulation depending on the desired values and the predicted values of energetic parameters

exclude from further consideration the types of coding and modulation, for which the desired value of transmission capacity is unattainable su is bedstvie restrictions on the range of power adjustment,

for all remaining types of coding and modulation determines the amount of frequency-time resource required to transfer the requested amount of data in the generated frame forward and reverse channels

summarize the required size of time-frequency resource of the N subscriber stations corresponding to the remaining types of coding and modulation with a maximum data transfer rate, and compare the amount with the available frequency-time resource generated frame

in the case of non-exceeding assign each subscriber station type of modulation and coding, as well as the corresponding transmission power and the value of time-frequency resource so as to minimize the average power generated frame under the condition that all necessary data

in case of exceeding the value of time-frequency resource is distributed between subscriber stations in accordance with their priority and assign each subscriber station type of modulation and coding with a maximum data rate and the corresponding transmit power.

Moreover, for example, as energy parameters using the signal-to-noise or signal-to-noise ratio, or signal-to - (interference + noise), or normalized to the transmission power of the listed options.

Under the quality is the understand your probability of bit error, or the probability of an error frame, or the probability of block error, or delay in the transmission of data, or the stability of the delay in the transmission of data, or any combination of these characteristics.

The required values of energy parameters for different types of coding and modulation is determined by the dependency of the quality of the energy parameter and the amount of data required for transmission.

Predict the amount of energy parameters generated by frame forward and reverse channels as a weighted sum of the measured energy parameters of previous frames.

The desired value of the transmission power linearly depend on the ratio of the desired and predicted values of the energy parameters for each type of coding and modulation.

The magnitude of the frequency-time resource required to transmit the required amount of data in the generated frame forward and reverse channels, determine the type of coding and modulation.

Average power generated frame minimize by choosing such a set of modulation types and coding for subscriber stations from various sets, which gives the minimum average power generated frame under the condition that all necessary data.

The distribution of time-frequency resource between subscriber stations in accordance with their priority OS is p thus, in the case of equal priority subscriber stations, each subscriber station allocate time-frequency resource, the magnitude of which is proportional to the desired frequency and time resource for each subscriber station, and when there are two groups of subscriber stations, one with high priority and the other with a low priority, if not possible to transfer all data of the subscriber stations in the group with high priority, each subscriber station group with high priority allocate time-frequency resource, the magnitude of which is proportional to the desired frequency and time resource for each subscriber station group with high priority, and the subscriber stations in the group with low priority time-frequency resource is not allocated, if all data of the subscriber stations in the group with the highest priority possible, the remaining time-frequency resource are distributed to each of the subscriber stations in the group with low priority in proportion to their required frequency and time resource.

The inventive method adaptive allocation of time-frequency resource, adaptive modulation, coding and power control in a communication system has a number of distinctive features in comparison with the known technical solutions, these differences in the aggregate allow upgraded the e efficient use of time-frequency resource, the selected communication system.

These distinctive features are as follows.

For each subscriber station determines the required values of energy parameters for different types of coding and modulation depending on a given amount of data needed to transmit the generated frame forward and reverse channels.

Predict the amount of energy parameters generated by frame forward and reverse channels according to the values of the capacities of the transmission and the measured energy parameters of previous frames.

Determine the required values of transmission capacity for different types of coding and modulation depending on the desired values and the predicted values of energy parameters.

Exclude from further consideration the types of coding and modulation, for which the desired value of transmission capacity is unattainable due to the restrictions on the range of power adjustment.

For all remaining types of coding and modulation determines the amount of frequency-time resource required to transfer the requested amount of data in the generated frame forward and reverse channels.

Summarize the required size of time-frequency resource of the N subscriber stations corresponding to the remaining types of coding and modulation with a maximum speed of transmission of the data, and compare the amount with the available frequency-time resource of the formed frame.

In the case of non-exceeding assign each subscriber station type of modulation and coding, as well as the corresponding transmission power and the value of time-frequency resource so as to minimize the average power generated frame under the condition that all necessary data.

In case of exceeding the value of time-frequency resource is distributed between subscriber stations in accordance with their priority and assign each subscriber station type of modulation and coding with a maximum data rate and the corresponding transmit power.

The aggregate of these transactions allows to solve the task of increasing the efficiency of the use of time-frequency resource allocated to the communication system, to reduce energy consumption during data transmission.

Description of the invention is illustrated by examples and drawings.

Figure 1 shows the structural diagram of the device with which to carry out the method-prototype [3].

Figure 2 shows the structural diagram of embodiments of the device, which carry out the inventive method.

Figure 3 illustrates the concepts of the current frame generated by the frame and previous frames, and ASU is installed and the relations between them.

Consider the implementation of the proposed method adaptive allocation of time-frequency resource, adaptive modulation, coding and power control in a communication system.

The communication system includes at least one base station and N subscriber stations served by the base station, where N takes on the values 1, 2, etc.

The communication system also includes other base stations serving other subscriber stations.

The base station transmits the data to the subscriber station via the direct channel and the subscriber stations transmit data to the base station via a reverse channel.

Direct channels from different base stations use the same frequency resource (bandwidth). Reverse channels of different subscriber stations use the same frequency resource.

Forward and reverse channels can use the same frequency resource in the temporary duplex or different frequency resources in a frequency duplex.

The data transmitted in the forward channel and designed with different subscriber stations, in this example, the implementation of the proposed method are separated by time, but can also be separated in time and frequency.

Data transmitted in a reverse channel from different subscriber stations, in this example implementation tawlae the second method are separated by time, but can also be separated in time and frequency.

The transmitter any base station system has the opportunity once in the frame to change the appearance of the coding and modulation of the transmitted data of the individual subscriber stations, as well as reallocate time-frequency resource of the direct channel between them.

Under the frame understand the throttling interval type of coding and modulation and assignment of time-frequency resource.

The transmitter any subscriber station system has the opportunity once in the frame to change the appearance of the coding and modulation of the transmitted data, and send data at any part of time-frequency resource frame backward channel.

Examples of the type of coding and modulation can be: convolutional code with rate coding 1/2 and four positional quadrature amplitude modulation (4-QAM); convolutional code with rate 2/3 coding and 4-QAM; convolutional code with rate coding and 1/2 16-QAM; or any other combination of one or more types of coding and modulation type.

Convolutional code and multi-quadrature amplitude modulation is described, for example, in joules. Had soured. Digital communication. M.: Radio and communication, 2000, chapters 4, 5 and 8 [4].

The terms "type of coding and modulation" and "modulation type and coding" are in the description of the proposed method of equal importance is the giving and respectively, are used in the description as identical.

The receiver of the base station and the receivers of the subscriber stations when receiving data have the possibility to measure the energy parameters characterizing the quality of reception of data.

As energy parameters are used, for example, the signal-to-noise or signal-to-noise ratio, or signal-to - (interference + noise), or normalized to the transmission power of the listed options.

During data transfer in the forward or in the reverse channel, you must take them with the specified capacity.

Under the as see, for example, the probability of bit error, or the probability of an error frame, or the probability of block error, or delay in the transmission of data, or the stability of the delay in the transmission of data, or any combination of these characteristics.

For each type of coding and modulation for each data volume that needs to be transferred, the known minimum values of energy parameters, ensuring the specified quality.

For example, typical for this communication system channel distribution can be obtained by the method of computer simulation of the dependence of the probability of block error ratio signal to noise ratio in the channel of distribution for all possible sizes of blocks of data transferred.

Let the set ka is esto - the probability of block error of 10-3.

Then the minimum value of the signal-to-noise ratio, giving the probability of block error of 10-3- the abscissa of the point on the graph according to the probability of block error ratio signal to noise ratio, the ordinate of which is equal to 10-3. Moreover, it is necessary to use a dependency corresponding to the block size of data transferred is equal to the amount of data that must be passed.

For a better understanding of the implementation of the proposed method is 2.

Figure 2 shows the base station 1, containing at least block 2 encoding and modulation unit 3 demodulation and decoding unit 9 measuring energy parameter and unit 4 adaptation, and one of the N present in the system subscriber stations served by the base station 1 and the subscriber station 5, containing, as a minimum, unit 6, demodulation and decoding unit 7 measurement of the energy parameter and the block 8 encoding and modulation.

Consider implementing the proposed method on the example of data transfer in the forward channel from base station 1 to the subscriber station 5 and in the reverse channel from the subscriber station 5 to the base station 1.

On the first N inputs of the base station 1 receives N signals containing the data you wish to transfer the N subscriber stations in the generated frame of the downlink channel. These N signals pic is ouput on the first N inputs of block 4 of adaptation.

Unit 4 adaptation signal is generated by the service, contains the type of coding and modulation for each of the N data signals and the description of the plot of time-frequency resource of the formed frame direct channel allocated for data transmission of each of the N subscriber stations, and also includes the kind of coding and modulation for the signal of each of the N subscriber stations and the description of the plot of time-frequency resource of the formed frame reverse channel allocated for data transmission from each of the N subscriber stations.

Under the area of time-frequency resource of the formed frame see, for example, part of the frame allocated to the subscriber station. Then the area of time-frequency resource block may be described by the magnitude of the displacement in time of the beginning and end of the segment relative to the beginning of the frame. This definition of a plot of time-frequency resource is applicable for both the forward channel frame and frame back channel.

The method of forming this service signal will be disclosed in detail hereinafter in the description of the proposed method.

From the first output unit 4 adaptation of the N signals containing the data received on the first N inputs of block 2 coding and modulation, to the second input of which receives a service signal from the second output unit 4 adaptation.

Unit 2 coding and modulation in accordance with receiving the major service signal performs coding and modulation of the N signals, contains the data, and generates a frame of the downlink channel in accordance with the areas of time-frequency resource assigned to the N subscriber stations.

Together with the N signals containing data generated in the frame of the direct channel transfer service signal containing information about the types of coding and modulation, and on the distribution of time-frequency resource between subscriber stations for the frame following the generated frame directly or through one or more frames. The information contained in the service signal will be called a service message.

The formed frame from the output unit 2 coding and modulation routed to the first output of the base station 1, and with the first base station 1 receives at the first input of subscriber stations 5 and respectively to the inputs of block 6 of the demodulation and decoding unit 7 measurement of the energy parameter.

In block 6 of the demodulation and decoding demodulator and decode the part of the received frame, the selected subscriber stations 5, using the information contained in the message of one of the previous received frames and describing used in the received frame types of coding and modulation and distribution of time-frequency resource of the received frame between subscriber stations.

In block 6 demodula the AI and decoding also demodulator and decode section of the received frame, contains service message, which is then used for decoding corresponding to this service message frame of the downlink channel and the coding and modulation, as well as forming the frame of the backward channel corresponding to this service message.

The data contained in the received frame and the intended subscriber station 5, from the output of block 6 demodulation and decoding arrive at the first subscriber station 5.

In block 7 of measuring energy parameter according to the received frame measured energy parameter.

The signal containing the measured energy parameter comes from the output of the unit 7 measurement of the energy parameter to the first input unit 8 encoding and modulation. To the second input unit 8 encoding and modulation signal from the second input of the subscriber stations 5, containing data intended for transmission to the base station 1.

In block 8 encoding and modulation carry out coding and modulation signal containing data and a signal containing the measured energy parameter.

The signal return path after encoding and modulation comes from the output of the unit 8 encoding and modulation on the second output of the subscriber station 5, and with him - to the second input of the base station 1, where it comes to the input of the demodulation unit 3 and Dec is tiravanija and to the input unit 9 measuring energy parameter.

In block 3, the demodulation and decoding perform demodulation and decoding received his signal and receive data, which are received from the second output to the second output of the base station 1, and the measured energy parameter, which comes from its first output to the second input of block 4 of adaptation.

In block 9 of measuring energy parameter according to the received frame measured energy parameter, which is supplied from the output unit 9 measuring energy parameter to the third input of the unit 4 adaptation.

In unit 4 adaptation adaptive distributed time-frequency resource frame forward and reverse channels, adaptive designate the type of modulation and coding and adaptive regulate the transmission power generated frames forward and reverse channels.

In more detail the operation of the proposed method can be described as follows:

First explain the concepts generated frame, the current frame and the previous frame and explain the temporal correlation between them (see figure 3).

The frame of the downlink channel, which is currently passed to the N subscriber stations and, in particular, the subscriber station 5, and also take on the N subscriber stations and, in particular, to the subscriber station 5 will be called the current frame. Let the current frame has the number i, where i takes the mn of the treatment 1, 2, etc.

The current frame of the downlink channel contains service message (figure 3 service message is marked as "SS"), describing the kinds of coding and modulation used for transmission data generated in the frame of the downlink channel from the base station 1 to N subscriber stations and, in particular, the subscriber station 5, and the areas of time-frequency resource of the formed frame direct channel allocated for transmission of the specified data and regular service message.

Service message also describes the types of coding and modulation used for transmission data generated in the frame of the backward channel from the N subscriber stations and, in particular, from the subscriber station 5 to the base station 1, and plots of time-frequency resource of the formed frame reverse channel allocated for transmission of the specified data.

In the above example, the generated frame immediately follows the current frame and has the number i+1.

The current frame of the downlink channel take on subscriber stations 5 using service messages received in the previous frame, in the example having the number i-1.

Also on the previous frame direct channel number i-1 measured at the subscriber station 5 energy parameter in the interval of the previous frame i-1 and the current frame of the downlink channel measured turn the Oh energy parameter. Figure 3 the measured energy parameter is set as "EP".

Transmit the current frame return path from the subscriber station 5 to the base station 1 using a service message received in the previous frame i-1. The current frame of the backward channel contains the measured energy parameter of the previous frame i-1.

Take the current frame of the reverse channel at the base station 1, containing the energy parameter of the current frame.

When the formation of a service message, the current frame using previously adopted energy parameters of previous frames, for example with numbers i-1, i-2, etc.

Let us consider the operations of the adaptive allocation of time-frequency resource frame forward and reverse channels, the adaptive assignment of modulation type and coding and adaptive adjustment of the transmission power in the generated frames forward and reverse channels.

At the base station 1 in block 4 of adaptation known how much data you want to transfer from the base station 1 to N subscriber stations in the generated frame of the downlink channel, and you also know how much data you want to transfer from the N subscriber stations to the base station 1 in the generated frame of the backward channel.

In unit 4 of adaptation for each of the N subscriber stations there are dependencies from C is achene energy parameter and the size of the block of transmitted data.

Determine in block 4 of adaptation required values of energy parameters for different types of coding and modulation depending on a given amount of data needed to transmit the generated frame forward and reverse channels.

For convenience in describing the operations of the proposed method we introduce the following notation.

SIZEDL(i+1) - dimension time-frequency resource available in the generated frame direct channel number i+1.

SIZEUL(i+1) - dimension time-frequency resource available in the generated frame backward channel number i+1.

The size of the time-frequency resource frame see, for example, the maximum number of modulation symbols that can be transmitted in this frame.

QoSDL(n), where- set quality of data transmission from the base station to the subscriber station n. In this example of implementation of the proposed method under as understand the probability of block errorblocks of transmitted data frame of the downlink channel.

QoSUL(n) is specified as a data transmission from the subscriber station number n to the base station. In this example of implementation of the proposed method under as understand the probability of block errorblocks before emich data frame of the backward channel.

In the description of example implementations of the proposed method as an energy parameter use signal/(noise + interference).

For each subscriber station determines the required values of energy parameters for different types of coding and modulation depending on the quality and quantity of data needed to transmit the generated frame forward and reverse channels.

We denote ByDL- the number of available types of coding and modulation in the direct channel communication system, where KDLtakes on the values 1, 2, etc.

We denote ByUL- the number of available types of coding and modulation in the return channel of the communication system, where KULtakes on the values 1, 2, etc.

Obtained, for example, by the method of computer simulation of the dependence of the probability of block error BLERDL(SNR,size,kDLfrom the signal-to-noise ratio SNR in the distribution channel, the block size of the transferred data size and the type of coding and modulation kDLwherefor direct channel for all possible dimensions of the block of transmitted data.

The dependences of the probability of block error BLERUL(SNR,size,kULfrom the signal-to-noise ratio SNR in the channel 20 of the distribution block size of the transferred data size and the type of coding and modulation kULwhere for the reverse channel for all possible dimensions of the block of transmitted data.

Such dependences are obtained, for example, typical for this communication system the distribution channel.

For each subscriber station n for each type of coding and modulation kDLdetermine the desired value of the energy parameter SNR*(n,kDL,i+1) in the form i+1-th frame of the downlink channel according to known dependencies for the encoding and modulation of kDLby the formula

where:

SNR(BLER,size,kDL) is the inverse function to the previously described functions BLERDL(SNR,size,kDL),

- specified quality when transferring data to the subscriber station n

sizeDL(n,i+1) is the amount of data that must be transmitted to subscriber station n in the form i+1-th frame of the downlink channel.

For each subscriber station n for each type of coding and modulation kULsimilarly, define the desired value of the energy parameter SNR*(n,kUL,i+1) in the form i+1-th frame of the backward channel.

We denote the SINRDL(n,l), where- measured energy parameter l-th frame of the downlink channel.

For each subscriber station n predict the value of the energy parameter the generated frame direct channel number i+1 measured energy parameters SINRDL(n,i-j), where- the amount of measured energy parameters involved in the forecast, and their corresponding values of capacity data PDL(n,i-j) at the subscriber station n by the following formula

where:

is a weighting factor that determines the weight of the i-j-th measured energy parameter in the forecast,

- normalizing multiplier

β - the option of decreasing weights.

When the prediction value of the energy parameter as an energy option, take the ratio of signal/(noise + interference), normalized to the transmit power.

For each subscriber station n for each type of coding and modulation kDLin the direct channel determines the desired value of the transmission powerin the form i+1-th frame of the downlink channel according to the required for this type of coding and modulation values of the energy parameter SNR*(n,kDL,i+1) and predicted values of the energy parameteri+1-th frame of the direct channel is according to the formula

where ΔPadd(kDL) - stock power transmission for the type of encoding and modulation of kDLin the direct channel.

For each subscriber station n for each type of coding and modulation KULin the reverse channel similarly define the desired value of the transmission powerin the form i+1-th frame of the reverse channel according to the required for this type of coding and modulation values of the energy parameter SNR*(n,kUL,i+1) and predicted values of the energy parameteri+1-th frame of the backward channel.

For each subscriber station n exclude from further consideration the types of coding and modulation in the direct channel, for which the desired value of the transmission powerin the form i+1-th frame of the downlink channel is unattainable due to the restrictions on the range of power adjustment, i.e. for whichwhereandrespectively the lower and upper limits of the adjustment range power direct channel.

For each subscriber station n exclude from further consideration the types of coding and modulation in the return channel, for which the desired value is e transmit power in the form i+1-th frame of the backward channel is unattainable due to the restrictions on the range of power adjustment, i.e. for whichwhereandrespectively the lower and upper limits of the adjustment range of the power return path.

Let in the direct channel for the n-th subscriber stations remained ToDL(n) type of modulation and coding. Enumerate their roomsso that a higher number corresponds to an increase in transmission speed and, accordingly, increase the required value of the energy parameter.

Let in the reverse channel for the n-th subscriber stations remained ToUL(n) type of modulation and coding. Enumerate their roomsso that a higher number corresponds to an increase in transmission speed and, accordingly, increase the required value of the energy parameter.

For all subscriber stations n for each kDL(n) of the forward channel modulation and coding determining the magnitude of the frequency-time resource r_sizeDL(n,kDL(n),i+1) generated by i+1-th frame of the downlink channel required to transmit the required data volume sizeDL(n,i+1) by the formula

where:

F(size,k) - function recalculate the size of the data block in the magnitude of frequency-time resource required for this unit using this type of modulation and encoding.

For example, to send the same bits using a convolutional code with rate coding 1/2, and modulation 4-QAM requires 1 modulation symbol.

Similarly, for all subscriber stations n for each kUL(n) remaining in the reverse channel modulation and coding determining the magnitude of the frequency-time resource

form i+1-th frame of the backward channel, is required to transfer the requested amount of data sizeUL(n,i+1).

Summarize the required size of time-frequency resource frame direct channel N subscriber stations corresponding to the remaining types of coding and modulation with a maximum data transfer rateand compare the amount with the available frequency-time resource generated frame direct channel SIZEDL(i+1). I.e. check the condition

If the condition is true, then assign each subscriber station n type of modulation and codingand the corresponding transmit powerand distribution which are time-frequency resource generated by i+1-th frame of the downlink channel so in order to minimize the average power generated frame direct channelassuming all necessary data.

I.e. find such a combination of types of coding and modulationwhich minimizes the expression

subject to the terms

This can be done, for example, a full search. The size of the plot of time-frequency resource generated by i+1-th frame of the downlink channel allocated to the subscriber station n equal toand the sequence of plots of time-frequency resource in the frame allocated to different subscriber stations, for example, arbitrary.

If the condition is not met, the value of time-frequency resource SIZEDL(i+1) generated frame direct channel distributed among the N subscriber stations in accordance with their priority and assign each subscriber station n type of modulation and coding ToDL(n) with a maximum data transfer rate and a corresponding transmit power.

With the same priority subscriber stations, each subscriber station n allocate time-frequency resourcewhose value is proportional to require the mu frequency and time resource for this subscriber stations by the formula

Accordingly recalculate the amount of data size*(n,i+1) subscriber station n, which can be passed in the form i+1-th frame of the downlink channel according to the formula

where F-1the inverse function to the function F, as described earlier.

When there are two groups of subscriber stations, one with high priority and the other with a low priority, then act, for example, as follows.

If not possible to transfer all data of the subscriber stations in the group with high priority, each subscriber station nHPgroups with high priority similarly allocate time-frequency resourcethe magnitude of which is proportional to the desired frequency and time resourcefor each subscriber station nHPgroups with high priority, and the subscriber stations of the low-priority time-frequency resource is not allocated.

The amount of data of the subscriber stations in the group with the highest priority that can be transmitted in the form i+1-th frame of the downlink channel, count similar to the previously described method.

If all data of the subscriber stations in the group with the highest priority possible, each subscriber station nH the group with the highest priority and assign the type of coding and modulation ToDL(nHPwith a maximum transmission rate and the corresponding transmit powerand the plot of time-frequency resource.

The remaining time-frequency resource are distributed to each of the subscriber stations in the group with low priority in proportion to their required frequency and time resource similar to the previously described method.

The amount of data of the subscriber stations in the group with the lowest priority that can be transmitted in the form i+1-th frame of the downlink channel, count similar to the previously described method.

Similarly summarize the required size of time-frequency resource frame reverse channel N subscriber stations corresponding to the remaining types of coding and modulation with a maximum data transfer rateand compare the amount with the available frequency-time resource generated frame reverse channel SIZEUL(i+1).

If the condition similar to the condition in the direct channel, is performed, similarly assign each subscriber station n type of modulation and codingand the corresponding transmit powerand distribute time-frequency resource groups is been created i+1-th frame of the backward channel so in order to minimize the average power generated by frame reverse channelassuming all necessary data.

If the condition is not met, the value of time-frequency resource SIZEUL(i+1) formed by frame reverse channel similarly distributed among the N subscriber stations in accordance with their priority and assign each subscriber station n type of modulation and coding ToUL(n) with a maximum data transfer rate and a corresponding transmit power

The amounts of data of subscriber stations that can be transmitted in the form i+1-th frame of the backward channel, count similar to the previously described method.

When describing implicitly meant that the forward and reverse channels of communication systems using different frequency bands, i.e. in the communication system, the frequency duplex.

The inventive method can be implemented in the system with a temporary duplex, code forward and reverse channels use the same frequency band and are separated in time.

Then the forward and backward channel use the same frame and minimize the power of this frame is similar to the earlier description.

The inventive method adaptive allocation of time-frequency resource, adaptive modulation, coding regulirovki power in the communication system has the following significant advantages over known in the art inventions.

First, the inventive method allows to minimize interference during data transmission in the forward and reverse channels of a communication system that leads to maximization of the capacity of communication systems.

Secondly, the inventive method allows to reduce energy consumption during data transfer.

Third, the inventive method improves the efficiency of the use of time-frequency resource allocated to the communication system.

These advantages are achieved by adaptive power control data together with adaptive allocation of time-frequency resource and adaptive modulation and coding, as well as taking into account the amount of data that must be passed in the forward and reverse channels.

1. Method of adaptive allocation of time-frequency resource, adaptive modulation, coding and power control in a communication system base station and N subscriber stations, in which each subscriber station must in every frame forward and reverse channels to provide the requested amount of data with a given quality, namely, that for each generated frame forward and reverse channels for each subscriber station determines the required values of energy parameters for different types of coding and modulation depending on the specific quality of the tion, measured values of the energy parameters in the current frame forward and reverse channels, transmit to the base station values of the energy parameters measured in the direct channel, characterized in that for each subscriber station determines the required values of energy parameters for different types of coding and modulation depending on a given amount of data needed to transmit the generated frame forward and reverse channels, predict the amount of energy parameters generated by frame forward and reverse channels according to the values of the capacities of the transmission and the measured energy parameters of previous frames to determine the required values of transmission capacity for different types of coding and modulation depending on the desired values, and the predicted values of energetic parameters, exclude from further consideration the types of coding and modulation, for which the desired value of transmission capacity is unattainable due to the restrictions on the range of power adjustment, for all remaining types of coding and modulation determines the amount of frequency-time resource required to transfer the requested amount of data in the generated frame forward and reverse channels, summarize the required size of time-frequency resource of the N subscriber stations is, corresponding to the remaining types of coding and modulation with a maximum data transfer rate, and compare the amount with the available frequency-time resource of the formed frame, if not exceeded assign each subscriber station type of modulation and coding, as well as the corresponding transmission power and the value of time-frequency resource so as to minimize the average power generated frame under the condition that all necessary data in excess of the value of time-frequency resource is distributed between subscriber stations in accordance with their priority and assign each subscriber station type of modulation and coding with a maximum data rate and the corresponding power transfer.

2. The method according to claim 1, characterized in that as the energy parameters using the signal-to-noise or signal-to-noise ratio, or signal-to-interference + noise ratio), or normalized to the transmission power of the listed options.

3. The method according to claim 1, characterized in that the quality of the estimate as the probability of bit error, or the probability of an error frame, or the probability of block error, or delay in the transmission of data, or the stability of the delay in the transmission of data, or any combination of these characteristics

4. The method according to claim 1, characterized in that the required values of energy parameters for different types of coding and modulation is determined by the dependency of the quality of the energy parameter and the amount of data required for transmission.

5. The method according to claim 1, wherein predicting the value of the energy parameters of the formed frame forward and reverse channels as a weighted sum of the measured energy parameters of previous frames.

6. The method according to claim 1, characterized in that the desired value of the transmission power determined in the form of linear dependence on the ratio of the desired and predicted values of the energy parameters for each type of coding and modulation.

7. The method according to claim 1, characterized in that the magnitude of the frequency-time resource required to transmit the required amount of data in the generated frame forward and reverse channels, determine the type of coding and modulation.

8. The method according to claim 1, characterized in that the average power generated frame minimize by choosing such a set of modulation types and coding for subscriber stations of the possible sets, which gives the minimum average power generated frame under the condition that all necessary data.

9. The method according to claim 1, characterized in that the distribution of time-frequency resources the sa between the subscriber stations in accordance with their priority realize thus in the case of equal priority subscriber stations, each subscriber station allocate time-frequency resource, the magnitude of which is proportional to the desired frequency and time resource for each subscriber station, and when there are two groups of subscriber stations, one with high priority and the other with a low priority, if it is not possible to transfer all the data of the subscriber stations in the group with high priority, each subscriber station group with high priority allocate time-frequency resource, the magnitude of which is proportional to the desired frequency and time resource for each subscriber station group with high priority, and the subscriber stations in the group with low priority time-frequency resource is not allocated, if all data of the subscriber stations in the group with the highest priority possible, the remaining time-frequency resource are distributed to each of the subscriber stations in the group with low priority in proportion to their required frequency and time resource.



 

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