CN115361091B - Down mixed broadcast unicast transmission method based on multi-user superposition transmission technology - Google Patents
Down mixed broadcast unicast transmission method based on multi-user superposition transmission technology Download PDFInfo
- Publication number
- CN115361091B CN115361091B CN202210831947.1A CN202210831947A CN115361091B CN 115361091 B CN115361091 B CN 115361091B CN 202210831947 A CN202210831947 A CN 202210831947A CN 115361091 B CN115361091 B CN 115361091B
- Authority
- CN
- China
- Prior art keywords
- service
- unicast
- broadcast
- base station
- modulation scheme
- 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.)
- Active
Links
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
- H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
- H04L1/0009—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the channel coding
-
- 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
- H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
- H04L1/0002—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the transmission rate
- H04L1/0003—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the transmission rate by switching between different modulation schemes
-
- 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
- H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
- H04L1/0023—Systems modifying transmission characteristics according to link quality, e.g. power backoff characterised by the signalling
- H04L1/0026—Transmission of channel quality indication
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
- H04W4/06—Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
- H04W4/50—Service provisioning or reconfiguring
-
- 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 discloses a downlink mixed broadcast unicast transmission method based on a multi-user superposition transmission technology, which comprises the following steps: the base station acquires channel state information of the broadcast service from the cell edge user, and determines a broadcast service code modulation scheme according to the channel state information; a base station selects a hot spot service area in a cell, and selects unicast service with proper channel conditions from the hot spot service area for superposition transmission with the broadcast service; and the base station nonorthogonally multiplexes the unicast service and the broadcast service to obtain a composite service, determines a coding modulation scheme of the composite service according to channel quality information fed back by a unicast service user, and replaces the coding modulation scheme of the broadcast service with the coding modulation scheme of the composite service. The invention can provide additional unicast service for the system on the premise of not influencing the coverage performance of the broadcast service, and improves the overall transmission efficiency of the unicast service.
Description
Technical Field
The invention relates to the technical field of digital information transmission, in particular to a downlink mixed broadcast unicast transmission method based on a multi-user superposition transmission technology.
Background
Cellular communication networks are subject to an explosive increase in traffic demand, and multimedia services such as high definition video are particularly prevalent. Because video services often have the characteristic of high overlap ratio among wide-area users, namely a small amount of popular content is requested by a large amount of users at the same time, the conventional unicast transmission method inevitably faces the problems of insufficient bandwidth and network congestion, and the problem can be effectively relieved by pushing the content in a broadcast mode. For this reason, in Rel-17 version of 5G, 3GPP has conducted related researches on a 5G NR (global 5G standard based on an entirely new air interface design of OFDM) multimedia broadcast Multicast (MBS) system based on a single cell point-to-multipoint (SC-PTM, single Cell Point To Multiploint) technology, in hope of realizing coverage of a broadcast service to a handheld terminal. It still faces problems such as the inability to support wide area big tower broadcasts effectively; in order to ensure the deep coverage of the cell, the frequency spectrum efficiency of the mobile phone broadcasting service is low; in physical layer transmission technology, there is a lack of depth interleaving and coded modulation is not optimized for multi-service broadcast channels.
The spectrum is an important strategic resource, and in order to fully utilize the 700M gold band, it is very necessary to improve the spectrum efficiency of the 5G MBS system. Compared with orthogonal multiplexing, the non-orthogonal multiplexing technology can remarkably improve the frequency spectrum efficiency of the system in an asymmetric service scene, and the multiplexing of broadcast service and unicast service is obviously an asymmetric service scene. Hybrid broadcast unicast transmissions based on non-orthogonal multiplexing have recently received widespread attention.
The LTE related proposal is widely studied for downlink non-orthogonal multiplexing transmission based on superposition coding, and is called a multi-user superposition transmission (mud) technique. The mud (Multiuser superposition transmission) technique is divided into three types, the first type is that the constellation symbols of the transmitting end QAM (quadrature amplitude modulation) are directly superimposed; the second type is a nonlinear superposition with Gray mapped complex constellation; the third class is flexible bit segmentation based on Gray mapped QAM complex constellation.
The existing mixed broadcast unicast transmission schemes based on non-orthogonal multiplexing all adopt a method of directly superposing at a transmitting end and carrying out SIC (Successive interference cancellation, serial interference elimination) at a receiving end. However, SIC can bring a significant computational burden and processing delay to unicast users, and when the broadcast service adopts time-frequency long interleaving, the delay brought will be more significant. And when there are multiple orthogonal multiplexing unicast services and broadcast services, each unicast user will face such a problem, and the requirement of 5G for low delay is not satisfied. When the receiving end adopts independent demapping and single-stage decoding (i.e. SIC is not carried out), compared with nonlinear superposition, the direct superposition is more suitable for a low-complexity and low-delay receiving scheme without SIC because the composite constellation map is not Gray mapped and can cause larger BICM capacity loss. Meanwhile, the existing solutions do not consider support for Adaptive Modulation and Coding (AMC) of unicast traffic, and when the unicast traffic is adaptive, how to ensure that coverage of broadcast traffic is not affected is also a problem to be considered.
Accordingly, there is a need for improvement and advancement in the art.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a downlink mixed broadcast unicast transmission method based on a multi-user superposition transmission technology aiming at the defects in the prior art.
In a first aspect, the present invention provides a downlink mixed broadcast unicast transmission method based on a multi-user superposition transmission technology, where the method includes:
the base station acquires channel state information of the broadcast service from the cell edge user, and determines a broadcast service code modulation scheme according to the channel state information;
a base station selects a hot spot service area in a cell, and selects unicast service with proper channel conditions from the hot spot service area for superposition transmission with the broadcast service;
and the base station nonorthogonally multiplexes the unicast service and the broadcast service to obtain a composite service, determines a coding modulation scheme of the composite service according to channel quality information fed back by a unicast service user, and replaces the coding modulation scheme of the broadcast service with the coding modulation scheme of the composite service.
In one implementation, the base station obtains channel state information of a broadcast service from a cell edge user, and determines a broadcast service code modulation scheme according to the channel state information, including:
the base station sends a channel state reference signal to a cell edge user;
the cell edge user carries out channel estimation according to the channel state reference signal and feeds back the signal state information of the broadcast service to the base station, wherein the channel state information comprises a receiving signal-to-noise ratio;
and the base station selects a proper broadcast service coding modulation scheme according to the signal state information, wherein the broadcast service coding modulation scheme comprises an effective constellation mapping order and a channel coding code rate.
In one implementation, the base station selects a hot spot service area in a cell, and selects unicast service with proper channel condition from the hot spot service area for overlapping transmission with the broadcast service, including:
the base station selects a hot spot service area in a cell;
and the base station sorts the channel state information of the unicast service users in the selected hot spot service area according to the channel state information fed back by the unicast service users in the cell, and selects unicast service with proper channel conditions to be transmitted in a superposition way with the broadcast service.
In one implementation manner, the determining the code modulation scheme of the composite service according to the channel quality value fed back by the unicast service user includes:
the unicast service user periodically measures channel quality information and maps the channel quality information into CQI value to report to the base station;
the base station selects a target code modulation scheme corresponding to the CQI value from preset code modulation schemes according to the CQI value, and takes the target code modulation scheme as the code modulation scheme of the composite service, wherein the code modulation scheme of the composite service comprises: the order of the complex constellation map and the channel coding rate.
In one implementation manner, the base station selects a target code modulation scheme corresponding to the CQI value from preset code modulation schemes according to the CQI value, and includes:
the base station determines a receiving signal-to-noise ratio range corresponding to the CQI value according to the CQI value;
and according to the receiving signal-to-noise ratio range, determining a target coding modulation scheme which corresponds to the receiving signal-to-noise ratio range from the preset coding modulation schemes.
In one implementation, the method further comprises:
and the base station informs the unicast service user of the channel control information of the code modulation scheme of the composite service.
In a second aspect, an embodiment of the present invention further provides a downlink hybrid broadcast unicast transmission system based on a multi-user superposition transmission technology, where the system includes: a base station and a cell, the base station comprising:
the broadcast service analysis module is used for acquiring the channel state information of the broadcast service from the cell edge user and determining a broadcast service coding modulation scheme according to the channel state information;
the unicast service determining module is used for selecting a hot spot service area in a cell, and selecting unicast service with proper channel conditions from the hot spot service area for superposition transmission with the broadcast service;
and the code modulation scheme determining module is used for nonorthogonally multiplexing the unicast service and the broadcast service to obtain a composite service, determining the code modulation scheme of the composite service according to channel quality information fed back by a unicast service user, and replacing the code modulation scheme of the broadcast service with the code modulation scheme of the composite service.
In one implementation, the broadcast service analysis module includes:
a signal transmitting unit, configured to transmit a channel state reference signal to a cell edge user by a base station;
a state receiving unit, configured to perform channel estimation according to the channel state reference signal by a cell edge user, and feed back signal state information of the broadcast service to the base station, where the channel state information includes a received signal-to-noise ratio;
and the scheme determining unit is used for selecting a proper broadcast service coding modulation scheme by the base station according to the signal state information, wherein the broadcast service coding modulation scheme comprises an effective constellation mapping order and a channel coding code rate.
In one implementation, the unicast traffic determination module includes:
the base station selects a hot spot service area in a cell;
and the base station sorts the channel state information of the unicast service users in the selected hot spot service area according to the channel state information fed back by the unicast service users in the cell, and selects unicast service with proper channel conditions to be transmitted in a superposition way with the broadcast service.
In one implementation, the code modulation scheme determining module includes:
the CQI value determining unit is used for periodically measuring channel quality information by the unicast service user and mapping the channel quality information into CQI value to report to the base station;
a scheme selection unit, configured to select, according to the CQI value, a target coded modulation scheme corresponding to the CQI value from preset coded modulation schemes, and use the target coded modulation scheme as a coded modulation scheme of the composite service, where the coded modulation scheme of the composite service includes: the order of the complex constellation map and the channel coding rate.
In one implementation, the scheme selection unit includes:
a signal-to-noise ratio range determining subunit, configured to determine, by the base station according to the CQI value, a received signal-to-noise ratio range corresponding to the CQI value;
and the target scheme determining subunit is used for determining a target code modulation scheme which corresponds to the receiving signal-to-noise ratio range from the preset code modulation schemes according to the receiving signal-to-noise ratio range.
In one implementation, the base station further includes:
and the information notifying module is used for notifying the unicast service user of the coded modulation scheme channel control information of the composite service.
In a third aspect, an embodiment of the present invention further provides a base station, where the base station includes a memory, a processor, and a downlink hybrid broadcast unicast transmission program based on a multi-user superposition transmission technology, where the downlink hybrid broadcast unicast transmission program based on the multi-user superposition transmission technology is stored in the memory and is executable on the processor, and when the processor executes the downlink hybrid broadcast unicast transmission program based on the multi-user superposition transmission technology, the steps of the downlink hybrid broadcast unicast transmission method based on the multi-user superposition transmission technology according to any one of the above schemes are implemented.
The beneficial effects are that: compared with the prior art, the invention provides a downlink mixed broadcast unicast transmission method based on a multi-user superposition transmission technology, firstly, a base station acquires channel state information of broadcast service from a cell edge user, and determines a broadcast service code modulation scheme according to the channel state information. Then, the base station selects a hot spot service area in the cell, and selects unicast service with proper channel condition from the hot spot service area to be transmitted in superposition with the broadcast service. And finally, the base station nonorthogonally multiplexes the unicast service and the broadcast service to obtain a composite service, determines a coding modulation scheme of the composite service according to channel quality information fed back by a unicast service user, and replaces the coding modulation scheme of the broadcast service with the coding modulation scheme of the composite service. The base station can adaptively adjust the code modulation scheme of the composite service according to the feedback of the non-orthogonal multiplexing unicast user, and provide additional unicast service for the system on the premise of not influencing the coverage performance of the broadcast service, thereby improving the overall transmission efficiency of the unicast service.
Drawings
Fig. 1 is a flowchart of a specific implementation of a downlink hybrid broadcast unicast transmission method based on a multi-user superposition transmission technique according to an embodiment of the present invention.
Fig. 2 shows the channel capacity of Gray-256-QAM for different bits in an AWGN channel.
Fig. 3 is a schematic diagram of an equivalent complex constellation mapping group (16, 64, 256-order NU-QAM).
Fig. 4 is a schematic diagram of channel capacity of broadcast service under different constellation mapping in an equivalent composite constellation mapping group.
Fig. 5 is a schematic diagram of channel capacity of unicast traffic under different constellation mapping in an equivalent composite constellation mapping group.
Fig. 6 is a schematic diagram of a constellation limited reachable capacity bound.
Fig. 7 is a schematic diagram of the present invention when the SFN architecture is employed.
Fig. 8 is a functional schematic diagram of a downlink hybrid broadcast unicast transmitter device based on a multi-user superposition transmission technique according to an embodiment of the present invention.
Fig. 9 is a schematic block diagram of a base station according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and effects of the present invention clearer and more specific, the present invention will be described in further detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
The embodiment provides a downlink mixed broadcast unicast transmission method based on a multi-user superposition transmission technology, firstly, a base station acquires channel state information of a broadcast service from a cell edge user, and determines a broadcast service code modulation scheme according to the channel state information. Then, the base station selects a hot spot service area in the cell, and selects unicast service with proper channel condition from the hot spot service area to be transmitted in superposition with the broadcast service. And finally, the base station nonorthogonally multiplexes the unicast service and the broadcast service to obtain a composite service, determines a coding modulation scheme of the composite service according to channel quality information fed back by a unicast service user, and replaces the coding modulation scheme of the broadcast service with the coding modulation scheme of the composite service. The base station of the embodiment can adaptively adjust the code modulation scheme of the composite service according to the feedback of the non-orthogonal multiplexing unicast user, and provide additional unicast service for the system on the premise of not influencing the coverage performance of the broadcast service, thereby improving the overall transmission efficiency of the unicast service.
Exemplary method
In specific implementation, as shown in fig. 1, the downlink mixed broadcast unicast transmission method based on the multi-user superposition transmission technology in this embodiment includes the following steps:
step S100, the base station obtains the channel state information of the broadcasting service from the cell edge user, and determines the broadcasting service code modulation scheme according to the channel state information.
In this embodiment, the transmission mode of the broadcast service may be adjusted according to the channel state information of the broadcast service of the edge user of the cell, so that the base station first obtains the channel state information of the broadcast service from the edge user of the cell, and then determines the broadcast service code modulation scheme according to the channel state information, thereby obtaining the transmission mode of the broadcast service. Compared with the traditional single-layer multimedia broadcasting system with fixed transmission mode, the embodiment can improve the spectrum efficiency of the broadcasting channel by adjusting the transmission mode.
In one implementation manner, the step S100 specifically includes the following steps:
step S101, a base station sends a channel state reference signal to a cell edge user;
step S102, a cell edge user carries out channel estimation according to the channel state reference signal and feeds back signal state information of the broadcast service to the base station, wherein the channel state information comprises a receiving signal-to-noise ratio;
step S103, the base station selects a proper broadcast service coding modulation scheme according to the signal state information, wherein the broadcast service coding modulation scheme comprises an effective constellation mapping order and a channel coding code rate.
Specifically, the base station firstly transmits a channel state reference signal to a cell edge user, and then selects a proper broadcast service coding modulation scheme according to channel state information such as a received signal-to-noise ratio of a cell edge broadcast service, wherein the broadcast service coding modulation scheme comprises an equivalent constellation mapping order and a channel coding code rate. The meaning of equivalent constellation mapping order here is that if the complex constellation mapping order is M, mb1=log, carrying Mb bits 2 M1 bits are used for transmission of the broadcast service,m1 is the equivalent constellation mapping order of the broadcast service.
When selecting the broadcast service code modulation scheme, for a fixed mode multimedia broadcast system, if the transmission mode is selected according to the worst channel condition in the covered area, the spectrum efficiency is low and the channel resources are wasted. One solution is to select an appropriate transmission mode based on the channel conditions in the coverage area. For example, in the weather of rain, snow and wind, the channel condition is bad, and the base station selects the most robust transmission mode, namely the combination of low-order constellation mapping and low coding rate; and when the weather condition is good, the channel condition is good, and the broadcast service terminal in the coverage area has better receiving signal to noise ratio, the base station selects the combination of the high-order equivalent constellation mapping and the high coding rate.
The equivalent constellation mapping order means that if the composite constellation mapping order is M, mb1=log, carrying Mb bits 2 And M1 bits are used for transmitting the broadcast service, and M1 is the equivalent constellation mapping order of the broadcast service. One broadcast service transmission mode, namely equivalent constellation mapping order and coding code rate, corresponds to one equivalent composite constellation mapping group. The equivalent here has two layers of meaning, one is that these composite constellations all use Mb1 bits for broadcast traffic; and secondly, the sum of mutual information of Mb1 bits of the composite constellation mapping diagrams used for the broadcasting service has the same signal-to-noise ratio threshold at the transmission rate of the selected mode. Any one of the sets of equivalent complex constellation mappings is equivalent to the transmission of broadcast traffic in the selected mode. A set of equivalent complex constellation mapping sets with different orders is designed for the transmission mode of a broadcast service, because unicast services superimposed on the broadcast service have a need for adaptively selecting a coding modulation scheme after the transmission mode of the broadcast service is selected.
After the transmission mode of the broadcast service is selected, an M-order composite constellation mapping diagram carrying Mb bits can be selected from the equivalent constellation mapping group corresponding to the transmission mode of the selected broadcast service according to the requirement of the unicast service. Different bits in a higher order composite constellation often exhibit Unequal Error Protection (UEP) characteristics, i.e., the reliability or transmission capability of the different bits is different. Fig. 2 shows the channel capacity versus signal-to-noise ratio for 8 bits in a Gray-256-QAM constellation map, and it can be seen that these 8 bits exhibit 4 different error protection capabilities. Since the reception threshold of the broadcast service is significantly lower than that of the unicast service, the most robust Mb1 bits among the Mb bits should be selected for the broadcast service. From the mutual information point of view, i.e. Mb1 bits with the largest bit channel capacity under the corresponding receiving signal-to-noise threshold should be selected. It should be noted that, for the case of mb1=2, the two bits in the composite constellation that determine the quadrant position are often the most robust bits. Bits 0 and 1 in fig. 2 are two bits determining the quadrant in Gray-256-QAM, and are more reliable than the remaining bits throughout the signal-to-noise ratio range.
For example, due to bad weather conditions, the cell covered by a certain period of time has bad channel conditions, so the base station selects the most robust broadcast service transmission mode, i.e. the equivalent constellation mapping order is 4, and the code rate is 1/2. At this time, an equivalent composite constellation mapping group is determined, and a composite constellation mapping diagram is selected according to the requirement of the superimposed unicast service. Those two bits of the composite constellation that determine the quadrant are used for broadcast traffic transmission and the remaining bits are used for transmission of the superimposed unicast traffic.
In order to accurately demodulate the information of the broadcast service at the broadcast service receiving end, the base station needs to inform the MCS of the composite service to the broadcast service terminal by means of control signaling, including composite constellation mapping, bit positions allocated to the broadcast service in the composite constellation mapping, and channel coding rate of the broadcast service.
Step 200, the base station selects a hot spot service area in the cell, and selects unicast service with proper channel condition from the hot spot service area to be transmitted in superposition with the broadcast service.
Specifically, the step S200 includes the steps of:
step S201, a base station selects a hot spot service area in a cell;
step S202, the base station sorts the channel state information of the unicast service users in the selected hot spot service area according to the channel state information fed back by the unicast service users in the cell, and selects unicast service with proper channel condition to be transmitted in superposition with the broadcast service.
Specifically, the base station of this embodiment first selects a hotspot service area in the cell, where unicast users in the hotspot service area have a higher unicast traffic demand. The base station adjusts related parameters such as a transmitting antenna pattern and the like to enable the direction of the hot spot service area to have higher antenna gain. In order to fully mine performance gain caused by superposition coding, a base station sequences channel state information of unicast users in a selected hot spot service area, selects unicast service with proper channel conditions to be transmitted in superposition with original broadcast service, and provides additional unicast transmission capability for a system on the premise of not influencing broadcast service coverage.
Step S300, the base station non-orthogonally multiplexes the unicast service and the broadcast service to obtain a composite service, determines a coding modulation scheme of the composite service according to channel quality information fed back by a unicast service user, and replaces the broadcast service coding modulation scheme with the coding modulation scheme of the composite service.
In one implementation, the step S300 includes the following steps:
step S301, a unicast service user periodically measures channel quality information and maps the channel quality information into CQI value to report to a base station;
step S302, the base station selects a target code modulation scheme corresponding to the CQI value from preset code modulation schemes according to the CQI value, and uses the target code modulation scheme as a code modulation scheme of the composite service, where the code modulation scheme of the composite service includes: the order of the complex constellation map and the channel coding rate.
Because in the existing cellular mobile communication network, the unicast service adopts Adaptive Modulation and Coding (AMC) technology to match the link throughput rate with the time-varying channel characteristics, so that the BLER is below a certain threshold. In order to ensure the service quality of the unicast service user, the scheme proposed by the embodiment also supports AMC. Specifically, the unicast service user periodically measures the downlink quality (i.e., channel quality information) and maps the channel quality information to CQI (Channel quality indicator, channel quality indication) value for feedback to the base station. And each CQI value corresponds to a receiving signal-to-noise ratio range, and the base station determines the receiving signal-to-noise ratio range corresponding to the CQI value according to the CQI value. And selecting a target code modulation scheme corresponding to the received signal-to-noise ratio range from preset code modulation schemes according to the received signal-to-noise ratio range, and taking the target code modulation scheme as the code modulation scheme of the composite service, wherein the code modulation scheme comprises the order of composite constellation mapping and the channel coding rate. And finally, the base station informs the unicast service user of the selected code modulation scheme of the composite service through the channel control information.
Specifically, after the transmission mode of the broadcast service is determined (the switching frequency of the transmission mode of the broadcast service is generally far lower than the frequency of the unicast service AMC), there is a group of complex constellation mappings with different orders, but equivalent to the current broadcast service mode can be used for unicast service selection. For example, when the broadcasting service mode is selected as the equivalent constellation mapping order is 4, the code rate is 5/6, and the threshold of the receiving signal to noise ratio is 5dB, one equivalent composite constellation mapping group meeting the requirement may be a group of composite constellation mapping shown in fig. 3.
Fig. 4 shows the channel capacity versus signal-to-noise ratio for broadcast traffic under several complex constellations as described in fig. 3, and it can be seen that these several complex constellation mappings are equivalent for the selected broadcast traffic transmission mode. Fig. 5 shows a plot of channel capacity versus snr for unicast traffic under several complex constellations as described in fig. 3, where the base station selects an appropriate target coding modulation scheme based on CQI (each CQI value corresponds to a received snr range) fed back by the unicast traffic user. If the signal-to-noise ratio of the unicast service user ranges from 10 dB to 15dB, NU-16-QAM and a proper coding rate are selected; for example, when the signal-to-noise ratio of the unicast service user ranges from 25 dB to 30dB, NU-256-QAM and a proper coding rate are selected.
The embodiment illustrates that the composite constellation obtained by nonlinear superposition of uniform QAM constellation images in MUST-Type2 according to a certain power ratio has larger gap from the reachable capacity boundary under some system working points, and the gap can be reduced by optimizing the composite constellation images, so that the spectrum efficiency of the system is further improved.
The equivalent constellation mapping order of the broadcast service is assumed to be 4, the code rate is 1/2, the signal-to-noise ratio threshold is 5dB, and the receiving signal-to-noise ratio of the unicast service user is 15dB. Fig. 6 plots the achievable capacity domain when different composite constellations are used (the capacity boundaries for time division multiplexing and gaussian input are also given at the same time for comparison), it can be seen that a composite constellation based on a non-linear superposition of uniform QAM constellations can provide a transmission rate of about 3.0bit/symbol for unicast traffic at a received signal-to-noise ratio of 15dB. And the APSK constellation diagram is used as a composite constellation map, and certain optimization is carried out under the transmission mode of the selected broadcast service and the receiving signal-to-noise ratio of the unicast service, so that certain shaping gain and better multi-user superposition gain can be provided. The achievable capacity of the non-uniform APSK composite constellation mapping obtained by optimization for the current embodiment is shown in fig. 6, and it can be seen that the optimized composite constellation mapping can provide a transmission rate about 3.2bit/symbol higher for unicast service without affecting broadcast service coverage (when the achievable capacity is compared, the receiving end assumes that independent demapping and single-stage decoding are adopted).
In another implementation manner, this embodiment may also use a Single Frequency Network (SFN) networking scheme, where the broadcast services transmitted by the base stations in different cells are identical signals, and each base station may multiplex the unicast service in each cell on the identical broadcast signal, and although the requirement of the single frequency network for simultaneous and same frequency and same signal is destroyed from the composite signal, since the (equivalent) power of the base layer broadcast service is often significantly higher than the (equivalent) power of the multiplexed enhancement layer unicast service, it may be regarded as noise introduced by the receiving end, so the invention may be extended to the SFN architecture, as shown in fig. 7.
In summary, the transmission mode of the broadcast service in this embodiment may be adjusted according to the channel condition, that is, the broadcast service is selected according to the channel state information such as the received signal to noise ratio of the broadcast service fed back by the cell edge user. A higher spectral efficiency of the broadcast service can be obtained compared to a broadcast system in which the transmission mode is fixed. The embodiment can also enable the multiplexed unicast user to have higher receiving signal-to-noise ratio by adjusting the related parameters of the transmitting antenna pattern so as to obtain higher superposition coding gain. In this embodiment, the broadcast service and the unicast service are multiplexed in a nonlinear superposition manner, which is specifically implemented by performing bit division on a Gray mapped composite constellation, and allocating bit subchannels with unequal error protection to broadcast and unicast services with larger channel condition differences. Compared with the existing broadcast unicast mixed transmission scheme, the embodiment considers the support of unicast service AMC, namely by introducing the concept of equivalent constellation mapping groups, a group of equivalent constellation mapping groups is designed for each supported broadcast service transmission mode, and the selection of the composite constellation mapping can be performed according to the channel condition of the unicast user under the condition of being transparent to the broadcast service.
Exemplary System
Based on the above embodiment, the present invention provides a downlink mixed broadcast unicast transmission system based on a multi-user superposition transmission technology, where the system includes: base station and cell. As shown in fig. 8, the base station includes: a broadcast service analysis module 10, a unicast service determination module 20 and a coded modulation scheme determination module 30. Specifically, the broadcast service analysis module 10 is configured to obtain channel state information of a broadcast service from a cell edge user, and determine a broadcast service code modulation scheme according to the channel state information. The unicast service determining module 20 is configured to select a hot spot service area in a cell, and select a unicast service with a suitable channel condition from the hot spot service area for overlapping transmission with the broadcast service. The code modulation scheme determining module 30 is configured to nonorthogonally multiplex the unicast service with the broadcast service to obtain a composite service, determine a code modulation scheme of the composite service according to channel quality information fed back by a unicast service user, and replace the broadcast service code modulation scheme with the code modulation scheme of the composite service.
In one implementation, the broadcast service analysis module includes:
a signal transmitting unit, configured to transmit a channel state reference signal to a cell edge user by a base station;
a state receiving unit, configured to perform channel estimation according to the channel state reference signal by a cell edge user, and feed back signal state information of the broadcast service to the base station, where the channel state information includes a received signal-to-noise ratio;
and the scheme determining unit is used for selecting a proper broadcast service coding modulation scheme by the base station according to the signal state information, wherein the broadcast service coding modulation scheme comprises an effective constellation mapping order and a channel coding code rate.
In one implementation, the unicast traffic determination module includes:
the base station selects a hot spot service area in a cell;
and the base station sorts the channel state information of the unicast service users in the selected hot spot service area according to the channel state information fed back by the unicast service users in the cell, and selects unicast service with proper channel conditions to be transmitted in a superposition way with the broadcast service.
In one implementation, the code modulation scheme determining module includes:
the CQI value determining unit is used for periodically measuring channel quality information by the unicast service user and mapping the channel quality information into CQI value to report to the base station;
a scheme selection unit, configured to select, according to the CQI value, a target coded modulation scheme corresponding to the CQI value from preset coded modulation schemes, and use the target coded modulation scheme as a coded modulation scheme of the composite service, where the coded modulation scheme of the composite service includes: the order of the complex constellation map and the channel coding rate.
In one implementation, the scheme selection unit includes:
a signal-to-noise ratio range determining subunit, configured to determine, by the base station according to the CQI value, a received signal-to-noise ratio range corresponding to the CQI value;
and the target scheme determining subunit is used for determining a target code modulation scheme which corresponds to the receiving signal-to-noise ratio range from the preset code modulation schemes according to the receiving signal-to-noise ratio range.
In one implementation, the base station further includes:
and the information notifying module is used for notifying the unicast service user of the coded modulation scheme channel control information of the composite service.
The working principle of each module in the downlink mixed broadcast unicast transmission device based on the multi-user superposition transmission technology in this embodiment is the same as the principle of each step in the above method embodiment, and will not be described here again.
Based on the above embodiment, the present invention also provides a base station, and a schematic block diagram of the base station may be shown in fig. 9. A base station may comprise one or more processors 100 (only one shown in fig. 9), a memory 101 and a computer program 102 stored in the memory 101 and executable on the one or more processors 100, for example a program for downlink hybrid broadcast unicast transmission based on a multi-user superposition transmission technique. The execution of the computer program 102 by one or more processors 100 may implement various steps in an embodiment of a method for downlink hybrid broadcast unicast transmission based on a multi-user superimposed transmission technique. Alternatively, the one or more processors 100, when executing the computer program 102, may implement the functions of the modules/units in the apparatus embodiment for downlink hybrid broadcast unicast transmission based on multi-user superposition transmission technology, which is not limited herein.
In one embodiment, the processor 100 may be a central processing unit (Central Processing Unit, CPU), but may also be other general purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), off-the-shelf programmable gate arrays (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
In one embodiment, the memory 101 may be an internal storage unit of the electronic device, such as a hard disk or a memory of the electronic device. The memory 101 may also be an external storage device of the electronic device, such as a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) card, a flash card (flash card) or the like, which are provided on the electronic device. Further, the memory 101 may also include both an internal storage unit and an external storage device of the electronic device. The memory 101 is used to store computer programs and other programs and data required by the base station. The memory 101 may also be used to temporarily store data that has been output or is to be output.
It will be appreciated by persons skilled in the art that the functional block diagram shown in FIG. 9 is merely a block diagram of some of the structures associated with the present inventive arrangements and is not limiting of the base station to which the present inventive arrangements may be applied, as a particular base station may include more or fewer components than shown, or may combine some of the components, or may have a different arrangement of components.
Those skilled in the art will appreciate that implementing all or part of the above-described methods in accordance with the embodiments may be accomplished by way of a computer program stored on a non-transitory computer readable storage medium, which when executed may comprise the steps of the embodiments of the methods described above. Any reference to memory, storage, operational database, or other medium used in embodiments provided herein may include non-volatile and/or volatile memory. The nonvolatile memory can include Read Only Memory (ROM), programmable ROM (PROM), electrically Programmable ROM (EPROM), electrically Erasable Programmable ROM (EEPROM), or flash memory. Volatile memory can include Random Access Memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms such as Static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual operation data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous Link DRAM (SLDRAM), memory bus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), among others.
In summary, the invention discloses a downlink mixed broadcast unicast transmission method based on a multi-user superposition transmission technology, which comprises the following steps: the base station acquires channel state information of the broadcast service from the cell edge user, and determines a broadcast service code modulation scheme according to the channel state information; a base station selects a hot spot service area in a cell, and selects unicast service with proper channel conditions from the hot spot service area for superposition transmission with the broadcast service; and the base station nonorthogonally multiplexes the unicast service and the broadcast service to obtain a composite service, determines a coding modulation scheme of the composite service according to channel quality information fed back by a unicast service user, and replaces the coding modulation scheme of the broadcast service with the coding modulation scheme of the composite service. The invention can provide additional unicast service for the system on the premise of not influencing the coverage performance of the broadcast service, and improves the overall transmission efficiency of the unicast service.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (13)
1. The downlink mixed broadcast unicast transmission method based on the multi-user superposition transmission technology is characterized by comprising the following steps:
the base station acquires channel state information of the broadcast service from the cell edge user, and determines a broadcast service code modulation scheme according to the channel state information;
a base station selects a hot spot service area in a cell, and selects unicast service with proper channel conditions from the hot spot service area for superposition transmission with the broadcast service;
and the base station nonorthogonally multiplexes the unicast service and the broadcast service to obtain a composite service, determines a coding modulation scheme of the composite service according to channel quality information fed back by a unicast service user, and replaces the coding modulation scheme of the broadcast service with the coding modulation scheme of the composite service.
2. The downlink mixed broadcast unicast transmission method based on multi-user superposition transmission technique according to claim 1, wherein said base station obtains channel state information of broadcast service from cell edge users, and determines a broadcast service code modulation scheme according to said channel state information, comprising:
the base station sends a channel state reference signal to a cell edge user;
the cell edge user carries out channel estimation according to the channel state reference signal and feeds back the signal state information of the broadcast service to the base station, wherein the channel state information comprises a receiving signal-to-noise ratio;
and the base station selects a proper broadcast service coding modulation scheme according to the signal state information, wherein the broadcast service coding modulation scheme comprises an equivalent constellation mapping order and a channel coding code rate.
3. The downlink mixed broadcast unicast transmission method based on multi-user superposition transmission technology according to claim 1, wherein said base station selects a hot spot service area in a cell, and selects unicast service with proper channel condition from said hot spot service area for superposition transmission with said broadcast service, comprising:
the base station selects a hot spot service area in a cell;
and the base station sorts the channel state information of the unicast service users in the selected hot spot service area according to the channel state information fed back by the unicast service users in the cell, and selects unicast service with proper channel conditions to be transmitted in a superposition way with the broadcast service.
4. The method for downlink mixed broadcast unicast transmission based on multi-user superposition transmission according to claim 3, wherein said determining the coded modulation scheme of said composite service according to the channel quality value fed back by the unicast service user comprises:
the unicast service user periodically measures channel quality information and maps the channel quality information into CQI value to report to the base station;
the base station selects a target code modulation scheme corresponding to the CQI value from preset code modulation schemes according to the CQI value, and takes the target code modulation scheme as the code modulation scheme of the composite service, wherein the code modulation scheme of the composite service comprises: the order of the complex constellation map and the channel coding rate.
5. The downlink mixed broadcast unicast transmission method based on multi-user superposition transmission technique according to claim 4, wherein said base station selects a target coding modulation scheme corresponding to said CQI value from preset coding modulation schemes according to said CQI value, comprising:
the base station determines a receiving signal-to-noise ratio range corresponding to the CQI value according to the CQI value;
and according to the receiving signal-to-noise ratio range, determining a target coding modulation scheme which corresponds to the receiving signal-to-noise ratio range from the preset coding modulation schemes.
6. The method for downlink mixed broadcast unicast transmission based on multi-user superposition transmission according to claim 1, further comprising:
and the base station informs the unicast service user of the channel control information of the code modulation scheme of the composite service.
7. A downlink hybrid broadcast unicast transmission system based on a multi-user superposition transmission technique, the system comprising: a base station and a cell, the base station comprising:
the broadcast service analysis module is used for acquiring the channel state information of the broadcast service from the cell edge user and determining a broadcast service coding modulation scheme according to the channel state information;
the unicast service determining module is used for selecting a hot spot service area in a cell, and selecting unicast service with proper channel conditions from the hot spot service area for superposition transmission with the broadcast service;
and the code modulation scheme determining module is used for nonorthogonally multiplexing the unicast service and the broadcast service to obtain a composite service, determining the code modulation scheme of the composite service according to channel quality information fed back by a unicast service user, and replacing the code modulation scheme of the broadcast service with the code modulation scheme of the composite service.
8. The downstream hybrid broadcast unicast transmission system based on the multi-user superposition transmission technique according to claim 7, wherein said broadcast service analysis module comprises:
a signal transmitting unit, configured to transmit a channel state reference signal to a cell edge user by a base station;
a state receiving unit, configured to perform channel estimation according to the channel state reference signal by a cell edge user, and feed back signal state information of the broadcast service to the base station, where the channel state information includes a received signal-to-noise ratio;
the scheme determining unit is used for selecting a proper broadcast service coding modulation scheme according to the signal state information by the base station, wherein the broadcast service coding modulation scheme comprises an equivalent constellation mapping order and a channel coding code rate.
9. The downlink mixed broadcast unicast transmission system based on multi-user superposition transmission technique according to claim 7, wherein said unicast service determination module comprises:
the base station selects a hot spot service area in a cell;
and the base station sorts the channel state information of the unicast service users in the selected hot spot service area according to the channel state information fed back by the unicast service users in the cell, and selects unicast service with proper channel conditions to be transmitted in a superposition way with the broadcast service.
10. The downlink mixed broadcast unicast transmission system based on multi-user superposition transmission technique according to claim 9, wherein said code modulation scheme determination module comprises:
the CQI value determining unit is used for periodically measuring channel quality information by the unicast service user and mapping the channel quality information into CQI value to report to the base station;
a scheme selection unit, configured to select, according to the CQI value, a target coded modulation scheme corresponding to the CQI value from preset coded modulation schemes, and use the target coded modulation scheme as a coded modulation scheme of the composite service, where the coded modulation scheme of the composite service includes: the order of the complex constellation map and the channel coding rate.
11. The downlink hybrid broadcast unicast transmission system based on the multi-user superposition transmission technique according to claim 10, wherein said scheme selection unit comprises:
a signal-to-noise ratio range determining subunit, configured to determine, by the base station according to the CQI value, a received signal-to-noise ratio range corresponding to the CQI value;
and the target scheme determining subunit is used for determining a target code modulation scheme which corresponds to the receiving signal-to-noise ratio range from the preset code modulation schemes according to the receiving signal-to-noise ratio range.
12. The downlink hybrid broadcast unicast transmission system based on multi-user superposition transmission technique according to claim 7, wherein said base station further comprises:
and the information notifying module is used for notifying the unicast service user of the coded modulation scheme channel control information of the composite service.
13. A base station, characterized in that the base station comprises a memory, a processor and a downlink mixed broadcast unicast transmission program based on a multi-user superposition transmission technology stored in the memory and operable on the processor, wherein the processor implements the steps of the downlink mixed broadcast unicast transmission method based on the multi-user superposition transmission technology according to any one of claims 1-6 when executing the downlink mixed broadcast unicast transmission program based on the multi-user superposition transmission technology.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210831947.1A CN115361091B (en) | 2022-07-15 | 2022-07-15 | Down mixed broadcast unicast transmission method based on multi-user superposition transmission technology |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210831947.1A CN115361091B (en) | 2022-07-15 | 2022-07-15 | Down mixed broadcast unicast transmission method based on multi-user superposition transmission technology |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115361091A CN115361091A (en) | 2022-11-18 |
| CN115361091B true CN115361091B (en) | 2023-04-25 |
Family
ID=84032540
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210831947.1A Active CN115361091B (en) | 2022-07-15 | 2022-07-15 | Down mixed broadcast unicast transmission method based on multi-user superposition transmission technology |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115361091B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007036116A1 (en) * | 2005-09-29 | 2007-04-05 | Huawei Technologies Co., Ltd. | A multiple method and system of broadcast service channel and unicast service channel |
| CN101388704A (en) * | 2008-10-16 | 2009-03-18 | 北京创毅视讯科技有限公司 | Transmission method and mobile communication system when overlapping uni-cast and multi-cast services |
| CN101416461A (en) * | 2006-05-01 | 2009-04-22 | 三星电子株式会社 | Apparatus and method for broadcast superposition and cancellation in a multi-carrier wireless network |
| CN113300814A (en) * | 2020-02-24 | 2021-08-24 | 国家广播电视总局广播电视科学研究院 | Mixed service transmission method and device storage medium based on multi-cell cooperation |
-
2022
- 2022-07-15 CN CN202210831947.1A patent/CN115361091B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007036116A1 (en) * | 2005-09-29 | 2007-04-05 | Huawei Technologies Co., Ltd. | A multiple method and system of broadcast service channel and unicast service channel |
| CN101416461A (en) * | 2006-05-01 | 2009-04-22 | 三星电子株式会社 | Apparatus and method for broadcast superposition and cancellation in a multi-carrier wireless network |
| CN101388704A (en) * | 2008-10-16 | 2009-03-18 | 北京创毅视讯科技有限公司 | Transmission method and mobile communication system when overlapping uni-cast and multi-cast services |
| CN113300814A (en) * | 2020-02-24 | 2021-08-24 | 国家广播电视总局广播电视科学研究院 | Mixed service transmission method and device storage medium based on multi-cell cooperation |
Non-Patent Citations (1)
| Title |
|---|
| 超 ; 刘广宇 ; 杨曾 ; 卜智勇 ; .基于OFDM的广播单播混合系统容量分析.天津大学学报.2010,(03),全文. * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115361091A (en) | 2022-11-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US7796938B2 (en) | Wireless transmitter and method that select a subcarrier based on subcarrier reception quality information | |
| US8311550B2 (en) | Radio communication control method, base station apparatus and user apparatus | |
| RU2421916C2 (en) | Transmitting device and method of broadcasting | |
| US7738592B2 (en) | Wireless communication apparatus and wireless communication method | |
| US7623589B2 (en) | Cooperative multiple-access using user-clustering and space-time-frequency coding techniques for higher reliability reception | |
| CN112217546B (en) | Method and apparatus for transmitting and receiving broadcast signal | |
| US20090141818A1 (en) | Wireless communication apparatus and wireless communication method in multicarrier communication | |
| EP1811700A1 (en) | Communication apparatus, communication system, and communication method | |
| US20120008517A1 (en) | Communication apparatus and communication method | |
| US20090296833A1 (en) | Apparatus for generating a set of radio parameters, a transmitter and a receiver | |
| US20070297533A1 (en) | Apparatus and methods for implementing hierarchical modulation and demodulation for geran evolution | |
| EP1531560A1 (en) | Radio communication base station device, radio communication mobile station device, and radio communication method | |
| CN101795152A (en) | SC-OFDMA-based satellite mobile communication system for forward link | |
| BRPI0612080A2 (en) | server base station selection in a wireless communication system | |
| JPWO2007083636A1 (en) | Radio transmission apparatus and radio transmission method | |
| JP2013519322A (en) | Integrated multi-data stream transmission technology | |
| CN101821984A (en) | Multiplexed beacon symbols for a wireless communication system | |
| CA2635741C (en) | Localized and distributed allocation multiplexing and control | |
| US20110268065A1 (en) | Apparatus and method for improving transmission efficiency in wireless communication system | |
| CN106464646A (en) | Signal transmission method and device | |
| US20190159139A1 (en) | Terminal apparatus, base station apparatus, and communication method | |
| US8280420B2 (en) | Multi-level saturation | |
| US8630313B2 (en) | Signal mapping method and communication device | |
| WO2008032973A1 (en) | Method for performing cooperative transmission in multi-carrier system | |
| JP2008042861A (en) | Communication system, terminal device, base station, and communication method |
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 |