Signal transmitting method based on LTE system for improving link throughput performance
Technical Field
The invention relates to the field of wireless communication, in particular to a signal transmitting method based on an LTE system.
Background
LTE (Long Term Evolution) is performed by 3GPP (The 3)rdGeneration Partnership Project (third Generation Partnership Project) the long term evolution of the technical standard of UMTS (Universal Mobile communications System) was instituted and initiated at the 3GPP Toronto TSGRAN #26 conference at 12 months 2004. The LTE system introduces OFDM (Orthogonal Frequency Division Multiplexing) and MIMO (Multi-Input)&Multi-Output, multiple-input multiple-Output) and the like, the spectral efficiency and the data transmission rate are significantly increased (in case of a 20M bandwidth 2X2MIMO at 64QAM, the theoretical maximum downlink transmission rate is 201Mbps, and after removing signaling overhead, the theoretical maximum downlink transmission rate is approximately 140Mbps, but according to the practical networking and terminal capability limitations, the downlink peak rate is generally considered to be 100Mbps, and the uplink transmission rate is 50Mbps), and various bandwidth allocations are supported: 1.4MHz, 3MHz, 5MHz, 10MHz, 15MHz, 20MHz and the like, and supports the global mainstream 2G/3G frequency band and some newly-added frequency bands, thereby the frequency spectrum allocation is more flexible, and the system capacity and the coverage are also obviously improved. The LTE system network architecture is more flat and simplified, and the complexity of network nodes and the system is reduced, so that the system time delay is reduced, and the network deployment and maintenance cost is also reduced. The LTE system supports interoperation with other 3GPP systems. The LTE system has two systems: FDD-LTE and TDD-LTE, frequency division duplex LTE systems and time division duplex LTE systems, the main difference between the two technologies being on the physical layer of the air interface (like frame structure, time)Sub-design, synchronization, etc.). The air interface uplink and downlink transmission of the FDD-LTE system adopts a pair of symmetrical frequency bands to receive and transmit data, and the uplink and downlink of the TDD-LTE system adopts the same frequency band to transmit on different time slots, so that TDD has higher frequency spectrum utilization rate compared with an FDD duplex mode.
However, in the multi-communication terminal LTE system, besides the problems of link estimation errors and the like that are common to the single-communication terminal LTE system, the multi-communication terminal LTE system also has the problems of multi-terminal diversity, inter-terminal interference, multi-terminal scheduling and the like, which makes the best-fit matching relationship between the pilot frequency iterative estimation and the resource configuration, which has been obtained from the analysis of the single-communication terminal LTE system, unsuitable for the multi-communication terminal LTE system, so that the best-fit matching relationship between the pilot frequency iterative estimation and the resource configuration of the broadcast link of the multi-communication terminal LTE system is worthy of study.
Disclosure of Invention
The purpose of the invention is realized by the following technical scheme.
According to an embodiment of the present invention, a signal transmission method based on an LTE system is provided, the method including the steps of:
s1, under the condition of link Rayleigh fading, presetting that the maximum number T of transmitting symbols in a data packet is greater than the number M of transmitting antennas of a base station, and the base station determines the most suitable pilot signal power according to the most suitable matching relation between pilot iterative estimation and resource allocation
M pilot signals are transmitted to a communication terminal having only one receive antenna.
S2, the communication terminal performs link estimation using the reception matrix for the pilot signal.
S3, presetting the number K of communication terminals in the system not less than the number M of base station transmitting antennas, the base station selecting the transmitting communication terminal group according to the communication terminal link information returned by the communication terminal.
S4, transmitting T-M data symbols at the system data power Pd for the selected M transmitting communication terminals in the data packet.
According to an embodiment of the present invention, the determining the best-fit pilot signal power according to the best-fit matching relationship between the pilot iterative estimation and the resource allocation at S1 includes:
when the maximum number of transmitted symbols T in a data packet satisfies M < T < 2M-1, the most suitable pilot signal power
Wherein P is statistical uniform transmitting power, process parameter
Transmitting pilot signals
According to an embodiment of the present invention, the determining the best-fit pilot signal power according to the best-fit matching relationship between the pilot iterative estimation and the resource allocation at S1 includes:
when the maximum number of transmitted symbols T in a data packet satisfies T2M-1, the most suitable pilot signal power
Wherein P is statistical uniform transmitting power, process parameter
Transmitting pilot signals
According to an embodiment of the present invention, the determining the best-fit pilot signal power according to the best-fit matching relationship between the pilot iterative estimation and the resource allocation at S1 includes:
when the maximum number of transmitted symbols T in a data packet satisfies T > 2M, the most suitable pilot signal power
Wherein P is statistical uniform transmitting power, process parameter
Transmitting pilot signals
According to an embodiment of the present invention, the performing, by the communication terminal at S2, link estimation using a reception matrix for pilot signals specifically includes:
setting the number of communication terminals in the system as K, wherein the link impact response of any communication terminal K is hk=[hk1,hk2,...,hkM]White gaussian noise nk=[nk1,nk2,...,nkM]The receive matrix for the pilot signal is:
and obtaining a link estimation result as the k link information of the communication terminal:
and returns it to the base station.
According to an embodiment of the present invention, the selecting, by the base station of S3, the transmitting communication terminal group according to the communication terminal link information returned by the communication terminal includes:
s31, initializing the waiting communication terminal group Γ 1 ═ 1., K }, and selecting the first transmitting communication terminal
Setting a transmitting communication terminal identification number i to be 2;
s32, adjusting the group of the waiting communication terminals,
wherein epsilon is 0.4,
link information indicating the nth transmitting communication terminal;
s33, selecting the ith transmitting communication terminal
Adjusting the identification number i of the transmitting communication terminal to be i + 1; if i < M, go to step S32;
s34, the finally determined transmitting communication terminal group is { pi (1),.. and pi (M) }, and the number of the selected transmitting communication terminals is equal to the number M of the base station transmitting antennas;
the system data power of S4 according to the embodiment of the invention
The signal transmitting method based on the LTE system deduces the most suitable matching relation of the pilot frequency iterative estimation and the resource allocation of the LTE link according to the LTE capacity of the multi-communication terminal on the basis of considering the estimation error of the link of the multi-communication terminal LTE system and the dispatching of the communication terminals in the multi-communication terminal environment, adopts the most suitable pilot frequency signal power to transmit pilot frequency signals with the number equal to that of the transmitting antennas of the base station and transmits data, optimizes the accuracy of the link estimation and improves the throughput performance of the LTE link.
Drawings
Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:
fig. 1 shows a flow chart of a signal transmission method based on an LTE system according to an embodiment of the present invention.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
According to an embodiment of the present invention, a signal transmission method based on an LTE system is provided, as shown in fig. 1, the method includes the steps of:
s1, under the condition of link Rayleigh fading, presetting that the maximum number T of transmitting symbols in a data packet is greater than the number M of transmitting antennas of a base station, and the base station determines the most suitable pilot signal power according to the most suitable matching relation between pilot iterative estimation and resource allocation
M pilot signals are transmitted to a communication terminal having only one receive antenna.
The determining the most suitable pilot signal power according to the most suitable matching relationship between the pilot iterative estimation and the resource allocation comprises:
when the maximum number of transmitted symbols T in a data packet satisfies M < T < 2M-1, the most suitable pilot signal power
Wherein P is statistical uniform transmitting power, process parameter
Transmitting pilot signals
When the maximum number of transmitted symbols T in a data packet satisfies T2M-1, the most suitable pilot signal power
Wherein P is statistical uniform transmitting power, process parameter
Transmitting pilot signals
When the maximum number of transmitted symbols T in a data packet satisfies T > 2M, the most suitable pilot signal power
Wherein P is statistical uniform transmitting power, process parameter
Transmitting pilot signals
S2, the communication terminal performs link estimation using the reception matrix for the pilot signal:
setting the number of communication terminals in the system as K, wherein the link impact response of any communication terminal K is hk=[hk1,hk2,...,hkM]White gaussian noise nk=[nk1,nk2,...,nkM]The receive matrix for the pilot signal is:
and obtaining a link estimation result as the k link information of the communication terminal:
and returns it to the base station;
s3, presetting the number K of communication terminals in the system to be not less than the number M of base station transmitting antennas, the base station selecting the transmitting communication terminal group according to the communication terminal link information returned by the communication terminal, specifically including the steps of:
s31, initializing the waiting communication terminal group Γ 1 ═ 1., K }, and selecting the first transmitting communication terminal
Setting a transmitting communication terminal identification number i to be 2;
s32, adjusting the group of the waiting communication terminals,
wherein epsilon is 0.4,
link information indicating the nth transmitting communication terminal;
s33, selecting the ith transmitting communication terminal
Adjusting the identification number i of the transmitting communication terminal to be i + 1; if i < M, go to step S32;
s34, the finally determined transmitting communication terminal group is { pi (1),.. and pi (M) }, and the number of the selected transmitting communication terminals is equal to the number M of the base station transmitting antennas;
s4, transmitting T-M data symbols in the data packet at system data power Pd for the selected M transmitting communication terminals
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.