CN114039706A - Space-time coding sending method based on novel reconfigurable intelligent surface - Google Patents
Space-time coding sending method based on novel reconfigurable intelligent surface Download PDFInfo
- Publication number
- CN114039706A CN114039706A CN202111310398.5A CN202111310398A CN114039706A CN 114039706 A CN114039706 A CN 114039706A CN 202111310398 A CN202111310398 A CN 202111310398A CN 114039706 A CN114039706 A CN 114039706A
- Authority
- CN
- China
- Prior art keywords
- user
- ris
- transmission
- space
- intelligent surface
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000000034 method Methods 0.000 title claims abstract description 21
- 230000005540 biological transmission Effects 0.000 claims description 81
- 238000005562 fading Methods 0.000 claims description 7
- 239000002131 composite material Substances 0.000 claims description 6
- 239000000654 additive Substances 0.000 claims description 3
- 230000000996 additive effect Effects 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims description 3
- 238000004891 communication Methods 0.000 description 7
- 238000005516 engineering process Methods 0.000 description 7
- 230000006872 improvement Effects 0.000 description 5
- 238000010295 mobile communication Methods 0.000 description 4
- 238000011161 development Methods 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 241000197727 Euscorpius alpha Species 0.000 description 1
- 238000013473 artificial intelligence Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000008054 signal transmission Effects 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/02—Arrangements for detecting or preventing errors in the information received by diversity reception
- H04L1/06—Arrangements for detecting or preventing errors in the information received by diversity reception using space diversity
- H04L1/0618—Space-time coding
- H04L1/0625—Transmitter arrangements
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/14—Relay systems
- H04B7/145—Passive relay systems
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/02—Arrangements for detecting or preventing errors in the information received by diversity reception
- H04L1/06—Arrangements for detecting or preventing errors in the information received by diversity reception using space diversity
- H04L1/0618—Space-time coding
- H04L1/0637—Properties of the code
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/0202—Channel estimation
- H04L25/0204—Channel estimation of multiple channels
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/0202—Channel estimation
- H04L25/0224—Channel estimation using sounding signals
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Abstract
The invention relates to a space-time coding sending method based on a novel reconfigurable intelligent surface, which comprises the following steps: step 1, a user A sends pilot frequency, a user B does not send signals, a control unit starts all M units of the novel reconfigurable intelligent surface, and step 2: user B sends the pilot frequency, and user A does not send the signal, and the control unit opens all M units on novel restructurable intelligent surface, step 3: in the first stage of space-time coding, a user A and a user B simultaneously send pilot frequency, and a control unit starts all M units of the novel reconfigurable intelligent surface, wherein the step 4 is as follows: in the second stage of space-time coding, user a and user B send pilot frequencies simultaneously, the control unit starts all M units of the novel reconfigurable intelligent surface, step 5: the base station demodulates x (0) and x (1) by using the signals received in the first and second stages; the scheme improves the system performance, and accordingly provides a quick and reliable sending method with low implementation complexity.
Description
Technical Field
The invention relates to a code sending method, in particular to a space-time code sending method based on a novel reconfigurable intelligent surface, and belongs to the technical field of coding in a mobile communication system.
Background
As the fifth generation mobile communication system (5G) enters the business stage, the development of the sixth generation mobile communication system (6G) opens the introduction. The 6G can meet various increasing communication requirements of people in the forms of full coverage, full spectrum, full application and strong safety, and potential research directions include terahertz communication, artificial intelligence, super-large-scale MIMO technology and the like.
The development of modern mobile communication reveals that randomness and uncertainty of a wireless channel are key factors influencing wireless transmission quality, and radio waves of a transmitter interact uncontrollably with various objects on a transmission path in a transmission process to cause reduction of signal quality of a receiving end. The reconfigurable intelligent surface obviously improves the transmission performance of the system by artificially adjusting the wireless channel environment, and provides a new idea for the development of future wireless communication. Reconfigurable intelligent surfaces consist of a regular array of carefully designed electromagnetic elements, usually composed of metals, media and tunable elements. By controlling the adjustable elements in the electromagnetic unit, electromagnetic parameters of the reflected electromagnetic wave, such as phase and amplitude, are altered in a programmable manner. Compared with the traditional relay communication, the RIS can work in a full-duplex mode, has higher spectrum utilization rate, does not need a radio frequency link, does not need large-scale power supply, and has advantages in power consumption and deployment cost. The conventional RIS is classified into a reflection-type smart surface and a transmission-type smart surface, and the new RIS can simultaneously reflect and transmit wireless signals on each unit, and is also called as STAR-RIS (simultaneous Transmitting and Reflecting RIS).
The reconfigurable intelligent surface is used for changing the propagation environment, plays a role of traditional relay, and can also directly modulate information. The reconfigurable intelligent surface can effectively and directly regulate and control the wave front and various electromagnetic parameters, such as phase, amplitude, frequency and even polarization, of an electromagnetic signal without complex baseband processing and radio frequency transceiving operation, so that the reconfigurable intelligent surface can be used for exploring a novel transmitter architecture to directly modulate the signal. In addition, the space-time block code is a codeWireless communicationTransmit diversity techniques for transmitting multiple copies of a data stream on multiple antennas and utilizing various received versions of the data to improve data transmissionThe reliability of (2). The invention combines STAR-RIS and STBC technology and provides a novel wireless communication scheme. The scheme modulates different versions of the data symbol through the reflection and transmission units on the STAR-RIS and carries out space-time coding to form the transmission diversity, thereby effectively reducing the error rate of a receiving end, improving the system capacity, having low calculation complexity and needing no additional device.
Disclosure of Invention
The invention provides a space-time coding sending method based on a novel reconfigurable intelligent surface, aiming at solving the problems in the prior art, the scheme aims to modulate data by controlling reflection and transmission coefficients on a STAR-RIS unit, then carry out space-time coding, improve system performance by utilizing a transmission diversity technology, and accordingly provide a sending method which is rapid, reliable and low in complexity. The scheme utilizes a novel Reconfigurable Intelligent Surface (RIS) capable of reflecting and transmitting simultaneously to realize Space-time Block coding (STBC) technology, and can improve system capacity.
In order to achieve the purpose, the technical scheme of the invention is as follows, the space-time coding sending method based on the novel reconfigurable intelligent surface comprises the following steps:
step 1, a user A sends pilot frequency, a user B does not send signals, a control unit starts all M units of the novel reconfigurable intelligent surface, the reflection coefficient of each unit is set to be 1, and the transmission coefficient is set to be 0; according to the transmitted pilot frequency, the base station estimates the channel h of the user A after the reflection of the novel reconfigurable intelligent surfaceA；
Step 2: a user B sends pilot frequency, a user A does not send signals, a control unit starts all M units of the novel reconfigurable intelligent surface, the transmission coefficient of each unit is set to be 1, and the reflection coefficient is set to be 0; according to the transmitted pilot frequency, the base station estimates the channel h of the user B after the transmission of the novel reconfigurable intelligent surfaceB；
And step 3: in the first stage of space-time coding, a user A and a user B simultaneously send pilot frequency, a control unit starts all M units of the novel reconfigurable intelligent surface, the reflection coefficient is set as x (0), and the transmission coefficient is set as x (1);
step 4: in the second stage of space-time coding, user A and user B send pilot frequency simultaneously, the control unit starts all M units of the novel reconfigurable intelligent surface, and the reflection coefficient is set as-x (1)*The transmission coefficient is set to x (0)*；
And 5: the base station demodulates x (0) and x (1) using the signals received in the first and second stages.
Wherein x (0) and x (1) respectively represent modulation symbols with power of 0.5, such as QPSK or QAM; x (·)*Indicating a conjugate operation. The novel reconfigurable intelligent surface has M units, and each unit can reflect and transmit signals by setting reflection parameters and transmission parameters. User A is in the reflection zone of novel reconfigurable intelligent surface, and user B is in the transmission zone of novel reconfigurable intelligent surface. User a, user B and the base station all have only 1 antenna.
As an improvement of the present invention, the STBC transmission scheme proposed by the present invention is divided into two stages, namely, a channel estimation stage and a data transmission stage. In the channel estimation phase, user A transmits the pilot, user B does not transmit the signal, and the control unit turns on all M cells of STAR-RIS and sets the reflection coefficient of the cell to 1 and the transmission coefficient to 0. In step 1, it is assumed that a direct channel between the base station and the user a is blocked by an obstacle, only a channel that the user a reaches the base station through STAR-RIS reflection exists, and since the user B is located behind the novel RIS, usually only a transmission channel exists, and through a Frequency-flat fading channel, a Discrete-time Equivalent Baseband Signal (Discrete-time Equivalent Baseband Signal) received by the base station is:
wherein x isp(n) indicates a pilot signal transmitted by the user a at the nth time;
denotes base station and STAR-RIS mthChannel at nth time between units;
a channel representing the nth time between the mth unit of STAR-RIS and user A; alpha is alpham(n) represents the reflection coefficient set at the nth time by the mth unit of RIS; w is aA(n) represents Additive White Gaussian Noise (AWGN), and typically the channel coherence time is much greater than the channel estimation and data transmission times, during which the channel can be considered to remain unchanged. For simplicity of presentation, the time number n can be removed in the following analysis. Since all reflection coefficients are set to 1, and x is known to the receiving endp(n), the composite channel between the base station and user a that undergoes STAR-RIS reflection can be found as:
as an improvement of the present invention, in step 2, assuming that at the time n +1, user B transmits pilot, user a does not transmit signal, the control unit turns on all M cells of STAR-RIS, and sets the transmission coefficient of the cell to 1 and the reflection coefficient to 0, and the discrete baseband equivalent signal received by user B is:
wherein the content of the first and second substances,
a channel representing the (n +1) th time instant between the mth unit of the RIS and user B; beta is am(n +1) represents the transmission coefficient set at the (n +1) th instant of the mth unit of the RIS; w is aB(n +1) represents AWGN noise. Since all transmission coefficients are set to 1, and the receiving end knows xp(n +1), the composite channel transmitted through the RIS between the base station and user B can be obtained as:
as an improvement of the present invention, step 3 is specifically as follows, during the data transmission, in order to realize STBC, the transmission of each set of data is divided into two phases, in the first phase, user A and user B transmit pilot frequency simultaneously, the control unit turns on all M cells of STAR-RIS, sets the reflection coefficient to x (0), and sets the transmission coefficient to x (1), i.e. alpha (1)m(n)＝x(0)，βmX (0) and x (1) herein denote data to be transmitted by STAR-RIS, respectively, and are symbols modulated by BPSK, QPSK, or the like; since the reflection and transmission coefficients of the same cell are such that the total power is 1, | x (0) & gtluminance2＝|x(1)|2Assuming that data transmission occurs at the nth time, the discrete baseband equivalent signal received by the base station is:
where P denotes the transmission power of users A and B, wd(n) represents AWGN noise.
As an improvement of the present invention, step 4 is embodied as follows, in the second phase of STBC, user A and user B transmit pilot simultaneously, the control unit turns on all M units of STAR-RIS, sets the reflection coefficient to-x (1)*The transmission coefficient is set to x (0)*I.e. alpham(n+1)＝-x(1)*，βm(n+1)＝x(0)*M-0, 1.., M-1. At this time, the discrete baseband equivalent signal received by the base station is:
wherein, x (·)*Indicating a conjugate operation.
As an improvement of the invention, the step 5 is specifically as follows: at the receiving end, the base station first removes the known pilot symbols and power to obtain:
and
then, using the result obtained in the channel estimation stage, the following is calculated:
and
assuming that the channel estimation is ideal, i.e.
Is composed of (formula five)]And [ formula nine ]]It is possible to obtain:
z(0)＝|hA|2x(0)+|hB|2x(0)+hAwd(n)+hBwd(n+1)*[ formula eleven ]]
From [ equation six ] and [ equation ten ], we can get:
as can be seen from [ formula eleven ] and [ formula twelve ], each signal reaches the receiving end through two paths, reducing the possibility of receiving simultaneous fading. Finally, by dividing by the channel parameters, one can get:
and
compared with the prior art, the invention has the advantages that the invention does not need complex baseband processing and radio frequency operation, and reduces the realization complexity and power consumption by modulating and transmitting data of the existing radio frequency signal; by carrying out space-time block coding on data, the diversity technology can be utilized to improve the system performance; since the STAR-RIS can transmit and reflect signals simultaneously, the signal coverage is extended and it is easier to arrange than the conventional RIS. The STAR-RIS based space-time block code technology provided by the invention can also be used in the scene when the user and the base station have multiple antennas.
Drawings
FIG. 1 is a STAR-RIS based STBC diagram;
fig. 2 bit error rate curve is compared.
The specific implementation mode is as follows:
for the purpose of enhancing an understanding of the present invention, the present embodiment will be described in detail below with reference to the accompanying drawings.
Example 1: referring to fig. 1 and 2, a space-time coding transmission method based on a novel reconfigurable intelligent surface includes the following steps:
step 1: a user A sends pilot frequency, a user B does not send signals, a control unit starts all M units of the novel reconfigurable intelligent surface, the reflection coefficient of each unit is set to be 1, and the transmission coefficient is set to be 0; according to the transmitted pilot frequency, the base station estimates the channel h of the user A after the reflection of the novel reconfigurable intelligent surfaceA；
Step 2: a user B sends pilot frequency, a user A does not send signals, a control unit starts all M units of the novel reconfigurable intelligent surface, the transmission coefficient of each unit is set to be 1, and the reflection coefficient is set to be 0; according to the transmitted pilot frequency, the base station estimates the channel h of the user B after the transmission of the novel reconfigurable intelligent surfaceB；
And step 3: in the first stage of space-time coding, a user A and a user B simultaneously send pilot frequency, a control unit starts all M units of the novel reconfigurable intelligent surface, the reflection coefficient is set as x (0), and the transmission coefficient is set as x (1);
step 4: in the second stage of space-time coding, user A and user B send pilot frequency simultaneously, the control unit starts all M units of the novel reconfigurable intelligent surface, and the reflection coefficient is set as-x (1)*The transmission coefficient is set to x (0)*；
And 5: the base station demodulates x (0) and x (1) using the signals received in the first and second stages.
Wherein x (0) and x (1) respectively represent modulation symbols with power of 0.5, such as QPSK or QAM; x (·)*Indicating a conjugate operation. The novel reconfigurable intelligent surface has M units, and each unit can reflect and transmit signals by setting reflection parameters and transmission parameters. User A is in the reflection zone of novel reconfigurable intelligent surface, and user B is in the transmission zone of novel reconfigurable intelligent surface. User a, user B and the base station all have only 1 antenna.
The STBC transmission scheme provided by the invention is divided into two stages, namely a channel estimation stage and a data transmission stage. In the channel estimation phase, user A transmits the pilot, user B does not transmit the signal, and the control unit turns on all M cells of STAR-RIS and sets the reflection coefficient of the cell to 1 and the transmission coefficient to 0. In step 1, it is assumed that a direct channel between the base station and the user a is blocked by an obstacle, only a channel that the user a reaches the base station through STAR-RIS reflection exists, and since the user B is located behind the novel RIS, usually only a transmission channel exists, and through a Frequency-flat fading channel, a Discrete-time Equivalent Baseband Signal (Discrete-time Equivalent Baseband Signal) received by the base station is:
wherein x isp(n) indicates a pilot signal transmitted by the user a at the nth time;
representing base station and STAR-RIS mth sheetThe channel at the nth time between the elements;
a channel representing the nth time between the mth unit of STAR-RIS and user A; alpha is alpham(n) represents the reflection coefficient set at the nth time by the mth unit of RIS; w is aA(n) represents Additive White Gaussian Noise (AWGN), and typically the channel coherence time is much greater than the channel estimation and data transmission times, during which the channel can be considered to remain unchanged. For simplicity of presentation, the time number n can be removed in the following analysis. Since all reflection coefficients are set to 1, and x is known to the receiving endp(n), the composite channel between the base station and user a that undergoes STAR-RIS reflection can be found as:
in step 2, assuming that at the time n +1, user B sends pilot frequency, user a does not send signal, the control unit starts all M cells of STAR-RIS, sets the transmission coefficient of the cell to 1, sets the reflection coefficient to 0, and the discrete baseband equivalent signal received by user B is:
wherein the content of the first and second substances,
a channel representing the (n +1) th time instant between the mth unit of the RIS and user B; beta is am(n +1) represents the transmission coefficient set at the (n +1) th instant of the mth unit of the RIS; w is aB(n +1) represents AWGN noise. Since all transmission coefficients are set to 1, and the receiving end knows xp(n +1), the composite channel transmitted through the RIS between the base station and user B can be obtained as:
step 3 is embodied in that during the data transmission, in order to implement STBC, the transmission of each set of data is divided into two phases, in the first phase, user a and user B transmit pilot simultaneously, the control unit turns on all M cells of STAR-RIS, sets the reflection coefficient to x (0), and the transmission coefficient to x (1), i.e. αm(n)＝x(0)，βmX (0) and x (1) herein denote data to be transmitted by STAR-RIS, respectively, and are symbols modulated by BPSK, QPSK, or the like; since the reflection and transmission coefficients of the same cell are such that the total power is 1, | x (0) & gtluminance2＝|x(1)|2Assuming that data transmission occurs at the nth time, the discrete baseband equivalent signal received by the base station is:
where P denotes the transmission power of users A and B, wd(n) represents AWGN noise.
Step 4 is embodied as follows, in the second phase of STBC, user A and user B transmit pilot simultaneously, the control unit turns on all M units of STAR-RIS, sets the reflection coefficient to-x (1)*The transmission coefficient is set to x (0)*I.e. alpham(n+1)＝-x(1)*，βm(n+1)＝x(0)*M-0, 1.., M-1. At this time, the discrete baseband equivalent signal received by the base station is:
wherein, x (·)*Indicating a conjugate operation.
The step 5 is as follows: at the receiving end, the base station first removes the known pilot symbols and power to obtain:
and
then, using the result obtained in the channel estimation stage, the following is calculated:
and
assuming that the channel estimation is ideal, i.e.
Is composed of (formula five)]And [ formula nine ]]It is possible to obtain:
z(0)＝|hA|2x(0)+|hB|2x(0)+hAwd(n)+hBwd(n+1)*[ formula eleven ]]
From [ equation six ] and [ equation ten ], we can get:
as can be seen from [ formula eleven ] and [ formula twelve ], each signal reaches the receiving end through two paths, reducing the possibility of receiving simultaneous fading. Finally, by dividing by the channel parameters, one can get:
and
the specific implementation mode is as follows: referring to fig. 1-2, consider a STAR-RIS assisted Uplink (Uplink) narrowband (Narrow-band) communication system, with a Base Station (BS) having an antenna. STAR-RIS has M units, each of which can reflect and transmit simultaneously the signal transmitted by the base station, with a reflection coefficient of alphamTransmission coefficient of betamWherein M is 1, 2. Since each cell is a passive, passive reflective element, 0 ≦ αm|≤1，0≤|βm| is less than or equal to 1, and | alpham|2+|βm|21. The RIS typically has a control unit that controls the coefficients of the individual reflection units. When the RIS is used as a signal relay, the control unit is usually acted upon by the base station or some particular user. In the internet of things or some special scenes, to save energy and reduce complexity, the RIS can also be used for the sensors to send data. When the RIS is used to directly modulate signals, the control unit can be a stand-alone device and establish contact with the user and the base station through D2D or WiFi technology. Suppose that user a has 1 antenna, located in front of STAR-RIS (the reflection area), and can receive signals reflected by it. User B has 1 antenna behind STAR-RIS (the transillumination zone) and can receive signals transmitted through it. Since the user can be located at both front and rear sides simultaneously, compared to the conventional RIS which can only reflect signals, STAR-RIS expands the coverage as shown in fig. 1. In addition, it is assumed that the control unit has established contact with the base station and the user A, B, ready for channel estimation and data transmission.
In order to verify the beneficial effects of the invention, the following simulation experiment is carried out: the constructed STAR-RIS consists of 128 cells, each cell reflecting and transmitting signals simultaneously, with the base station being 50 meters from the STAR-RIS. User A and user B are 50 meters away from STAR-RIS, respectively, and the signal transmission power of user A and user B are both 27 dBm. Assuming that the direct channel between the base station and the user is blocked, i.e. there is no direct channel, there are Rayleigh (Rayleigh) fading channels between the base station and STAR-RIS and between STAR-RIS and the user, and the path fading index is 2.2. The reference distance is 1 meter and the path loss at the reference distance is-30 dB. STAR-RIS sets the reflection and transmission coefficients to QPSK signal with power of 0.5, and the base station counts the Bit Error Rate (BER) of all received data. In the conventional method, only user a transmits a pilot signal since the RIS can only reflect signals. For the sake of fairness, it is assumed that the transmission power of user a is 30dBm, and RIS sets the reflection coefficient to a QPSK signal with power 1. Figure 2 shows the BER curves compared to demonstrate the gain introduced by transmit diversity.
It should be noted that the above-mentioned embodiments are not intended to limit the scope of the present invention, and all equivalent modifications and substitutions based on the above-mentioned technical solutions are within the scope of the present invention as defined in the claims.
Claims (10)
1. A space-time coding sending method based on a novel reconfigurable intelligent surface is characterized by comprising the following steps:
step 1, user A sends pilot frequency, user B does not send signal,
step 2: user B transmits a pilot, user a does not transmit a signal,
and step 3: in the first phase of space-time coding, user a and user B transmit pilots simultaneously,
and 4, step 4: in the second phase of space-time coding, user a and user B transmit pilots simultaneously,
and 5: the base station demodulates x (0) and x (1) by using the signals received in the first and second stages;
where x (0) and x (1) each represent a modulation symbol having a power of 0.5.
2. A space-time coding transmission method based on a novel reconfigurable intelligent surface according to claim 1 is characterized in that in step 1, a user A sends pilot frequency, a user B does not send signals, a control unit starts all M units of the novel reconfigurable intelligent surface, the reflection coefficient of each unit is set to 1, and the transmission coefficient is set to 0; according to the transmitted pilot frequency, the base station estimates the channel h of the user A after the reflection of the novel reconfigurable intelligent surfaceA。
3. According to claim2, the space-time coding transmission method based on the novel reconfigurable intelligent surface is characterized in that in the step 1, the step 2: a user B sends pilot frequency, a user A does not send signals, a control unit starts all M units of the novel reconfigurable intelligent surface, the transmission coefficient of each unit is set to be 1, and the reflection coefficient is set to be 0; according to the transmitted pilot frequency, the base station estimates the channel h of the user B after the transmission of the novel reconfigurable intelligent surfaceB。
4. A space-time coding transmission method based on a novel reconfigurable intelligent surface according to claim 3, characterized in that in step 1, step 3: in the first stage of space-time coding, a user A and a user B simultaneously send pilot frequency, a control unit starts all M units of the novel reconfigurable intelligent surface, the reflection coefficient is set to be x (0), and the transmission coefficient is set to be x (1).
5. A space-time coding transmission method based on a novel reconfigurable intelligent surface as claimed in claim 4, wherein in step 1, step 4: in the second stage of space-time coding, user A and user B send pilot frequency simultaneously, the control unit starts all M units of the novel reconfigurable intelligent surface, and the reflection coefficient is set as-x (1)*The transmission coefficient is set to x (0)*。
6. A space-time coding transmission method based on novel reconfigurable intelligent surface according to claim 2, characterized in that in step 1, it is assumed that the direct channel between the base station and user a is blocked by an obstacle, only the channel that user a reaches the base station via STAR-RIS reflection exists, and since user B is located behind the novel RIS, only the transmission channel exists in general, and the Discrete-time Equivalent Signal (Discrete-time Equivalent base Signal) received by the base station is:
wherein，xp(n) indicates a pilot signal transmitted by the user a at the nth time;
a channel representing the nth time instant between the base station and the mth unit of STAR-RIS;
a channel representing the nth time between the mth unit of STAR-RIS and user A; alpha is alpham(n) represents the reflection coefficient set at the nth time by the mth unit of RIS; w is aA(n) represents Additive White Gaussian Noise (AWGN), and the channel coherence time is usually much longer than the channel estimation and data transmission time, during which the channel can be considered to remain unchanged, since all reflection coefficients are set to 1 and x is known to the receiving endp(n), the composite channel between the base station and user a that undergoes STAR-RIS reflection can be found as:
7. a space-time coding transmission method based on a novel reconfigurable intelligent surface according to claim 3, characterized in that in step 2, at the time n +1, user B transmits pilot frequency, user A does not transmit signal, the control unit starts all M units of STAR-RIS, sets the transmission coefficient of the unit to 1, sets the reflection coefficient to 0, and the discrete baseband equivalent signal received by user B is:
wherein the content of the first and second substances,
a channel representing the (n +1) th time instant between the mth unit of the RIS and user B; beta is am(n +1) denotes that the m-th unit of RIS is set at the (n +1) -th timeThe transmission coefficient of (a); w is aB(n +1) represents AWGN noise, all transmission coefficients are set to 1, and x is known to the receiving endp(n +1), the composite channel transmitted through the RIS between the base station and user B can be obtained as:
8. a space-time coding transmission method based on novel reconfigurable intelligent surface according to claim 4, characterized in that step 3 is specifically as follows, during the data transmission process, the transmission of each group of data is divided into two phases, in the first phase, user A and user B simultaneously transmit pilot, the control unit starts all M units of STAR-RIS, sets the reflection coefficient to x (0), and sets the transmission coefficient to x (1), that is, αm(n)＝x(0)，βmX (0) and x (1) herein denote data to be transmitted by STAR-RIS, respectively, and are symbols modulated by BPSK, QPSK, or the like; since the reflection and transmission coefficients of the same cell are such that the total power is 1, | x (0) & gtluminance2＝|x(1)|2Assuming that data transmission occurs at the nth time, the discrete baseband equivalent signal received by the base station is:
where P denotes the transmission power of users A and B, wd(n) represents AWGN noise.
9. A space-time coding transmission method based on novel reconfigurable intelligent surface as claimed in claim 5, characterized in that, in step 4, specifically, in the second phase of STBC, user A and user B transmit pilot frequency simultaneously, the control unit turns on all M units of STAR-RIS, and sets the reflection coefficient to-x (1)*The transmission coefficient is set to x (0)*I.e. alpham(n+1)＝-x(1)*，βm(n+1)＝x(0)*M-1, where the discrete baseband equivalent signal received by the base station is:
wherein, x (·)*Indicating a conjugate operation.
10. A space-time coding sending method based on a novel reconfigurable intelligent surface according to claim 1, characterized in that step 5 specifically includes the following steps: at the receiving end, the base station first removes the known pilot symbols and power to obtain:
and
then, using the result obtained in the channel estimation stage, the following is calculated:
and
assuming that the channel estimation is ideal, i.e.
Is composed of (formula five)]And [ formula nine ]]It is possible to obtain:
z(0)＝|hA|2x(0)+|hB|2x(0)+hAwd(n)+hBwd(n+1)*[ formula eleven ]]
From [ equation six ] and [ equation ten ], we can get:
as can be seen from [ formula eleven ] and [ formula twelve ], each signal reaches the receiving end through two paths, reducing the probability of receiving simultaneous fading, and finally, by dividing by the channel parameters, we can obtain:
and
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111310398.5A CN114039706B (en) | 2021-11-04 | 2021-11-04 | Space-time coding transmitting method based on novel reconfigurable intelligent surface |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111310398.5A CN114039706B (en) | 2021-11-04 | 2021-11-04 | Space-time coding transmitting method based on novel reconfigurable intelligent surface |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114039706A true CN114039706A (en) | 2022-02-11 |
| CN114039706B CN114039706B (en) | 2024-02-27 |
Family
ID=80143104
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111310398.5A Active CN114039706B (en) | 2021-11-04 | 2021-11-04 | Space-time coding transmitting method based on novel reconfigurable intelligent surface |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114039706B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114826450A (en) * | 2022-05-17 | 2022-07-29 | 南京航空航天大学 | Statistical channel-based traversal rate analysis method and phase optimization method in STAR-RIS auxiliary NOMA system |
| WO2024011577A1 (en) * | 2022-07-15 | 2024-01-18 | Lenovo (Beijing) Limited | Power control scheme for active ris based on network requirements and rrc connection states |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113225276A (en) * | 2021-05-08 | 2021-08-06 | 东南大学 | Semi-blind channel estimation method for intelligent reflector-oriented auxiliary communication system |
-
2021
- 2021-11-04 CN CN202111310398.5A patent/CN114039706B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113225276A (en) * | 2021-05-08 | 2021-08-06 | 东南大学 | Semi-blind channel estimation method for intelligent reflector-oriented auxiliary communication system |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114826450A (en) * | 2022-05-17 | 2022-07-29 | 南京航空航天大学 | Statistical channel-based traversal rate analysis method and phase optimization method in STAR-RIS auxiliary NOMA system |
| CN114826450B (en) * | 2022-05-17 | 2023-06-02 | 南京航空航天大学 | Statistical channel-based traversal rate analysis method and phase optimization method in STAR-RIS auxiliary NOMA system |
| WO2024011577A1 (en) * | 2022-07-15 | 2024-01-18 | Lenovo (Beijing) Limited | Power control scheme for active ris based on network requirements and rrc connection states |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114039706B (en) | 2024-02-27 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US7831201B2 (en) | Co-channel wireless communication methods and systems using relayed wireless communications | |
| CN112865893B (en) | Intelligent reflector assisted SM-NOMA system resource allocation method | |
| AU2004223381B2 (en) | Co-channel wireless communication methods and systems using nonsymmetrical alphabets | |
| EP1489772B1 (en) | A self - adapting weighted space time transmitting diversity method and system thereof | |
| US20070093273A1 (en) | Distributed base station, communication system, and signal transmission method thereof | |
| CN114039706B (en) | Space-time coding transmitting method based on novel reconfigurable intelligent surface | |
| CN101395821A (en) | Scheduling multi-user transmission in the downlink of a multi-antenna wireless communication system | |
| CN104104425A (en) | Multi-user MIMO (multiple input multiple output) adaptive receiving method based on expectation and interference signal relations | |
| CN101895911B (en) | Self-adaption transmission method utilizing channel statistical information in multi-base station cooperative transmission system | |
| CN113938891B (en) | Reflective-surface-assisted user node untrusted NOMA network secure communication method | |
| CN113708819B (en) | Non-orthogonal multiple access method based on novel reconfigurable intelligent surface | |
| Abdullah et al. | Combining relaying and reflective surfaces: Power consumption and energy efficiency analysis | |
| CN115967948A (en) | Mobile vehicle-mounted network downlink secure communication method based on intelligent reflecting surface of unmanned aerial vehicle | |
| CN116015503A (en) | Multi-reconfigurable intelligent surface selection method in wireless communication system considering aggregated interference | |
| CN110535796B (en) | Low-complexity space-frequency self-adaptive anti-interference channel equalization method | |
| CN113839702B (en) | Full-duplex communication method based on reconfigurable intelligent surface | |
| Tran et al. | Combining multi-RIS and relay for performance improvement of multi-user NOMA systems | |
| CN114389656B (en) | Antenna selection and symbol-level precoding joint design method for ultra-large-scale MIMO | |
| CN111082902B (en) | Large-scale antenna system signal detection method based on big data statistical characteristics | |
| CN115276732B (en) | Bidirectional relay network power distribution method and device based on sum rate maximization | |
| Sheng | Optimal power allocation in STAR-RIS for CoMP transmission | |
| Zhang et al. | Recent advances in integrated sensing and communication: a synergistic perspective | |
| Liu et al. | Performance analysis of FSO/THz-RF dual-hop link based on NOMA | |
| CN117692964A (en) | Average block length optimization method for RIS combined relay auxiliary URLLC system short packet communication | |
| CN117979341A (en) | Multi-antenna terahertz rate division multiple access system interruption performance analysis method based on hardware damage |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |