WO2012119373A1

WO2012119373A1 - Link performance perceiving method based on heterogeneous network convergence of wlan and lte

Info

Publication number: WO2012119373A1
Application number: PCT/CN2011/078102
Authority: WO
Inventors: 衡伟; 张金宝; 吴建波; 印芷漪; 张威; 王婉苓
Original assignee: 东南大学
Priority date: 2011-03-08
Filing date: 2011-08-08
Publication date: 2012-09-13
Also published as: CN102123411B; CN102123411A

Abstract

A link performance perceiving method based on heterogeneous network convergence of WLAN and LTE is designed on the basis of heterogeneous network convergence of wireless local area network WLAN and long term evolution LTE. Average real-time block mutual information MI of code blocks under a plurality of channel parameters in a wireless network and packet error rate PER of a wireless network communication system are determined; a mapping relation between the average real-time block mutual information MI and the packet error rate PER is established through a function model; and link performance is perceived according to the mapping relation between the PER and the average real-time block mutual information MI. The invention is an improved link performance perceiving method, which can simplify a physical layer link performance perceiving model of the wireless communication system, and carry out simple and accurate link performance perception.

Description

Link performance sensing method based on WLAN and LTE heterogeneous network convergence

Technical field

The invention belongs to the field of wireless communication technologies, and relates to a wireless local area network WLAN and a long-term evolution LTE heterogeneous network convergence and link performance sensing technology, and proposes a link performance sensing method based on WLAN and LTE heterogeneous network convergence.

Background technique

The 3GPP LTE (Long Term Evolution) project is an evolution of the 3G standard. It improves and enhances 3G air access technology, and adopts advanced wireless communication technologies such as OFDM, MIMO, and all-IP networking. As the only standard for 3G wireless network evolution, 3GPP LTE can provide downlink 100Mbit/ _s and uplink 50Mbps peak rate in 20MHz spectrum bandwidth, which significantly improves the performance of cell edge users, greatly improves cell capacity, and reduces system delay. . As an enhancement and evolution of existing 3G technologies, LTE is the latest generation of cellular mobile communication network technology.

802.11η combines several advanced technologies, including Orthogonal Frequency Division Multiplexing (OFDM), Multiple Input Multiple Output

(MIMO) 20MHz and 40MHz channels, 2.4GHz and 5GHz dual bands, etc., while ensuring

Compatible communication capabilities of the 802.11 protocol. From the performance indicators, 802.11η has become the mainstream of the next generation.

WLAN technology, which achieves high speeds not only from MIMO technology, but also from OFDM technology.

MIMO-OFDM technology achieves spatial diversity by using array antennas in OFDM transmission systems, improves signal quality, and increases multipath tolerance, which improves the effective transmission rate of wireless networks.

802.11η supports the 2.4GHz band and the 5GHz band, and the quality and speed of wireless transmission are greatly improved.

The link performance notification can reflect the instantaneous state of the wireless channel to the high-level module of the system through one or several simple quantities, thereby realizing the interaction of the cross-layer information and optimizing the overall performance of the system. After the 802.11n and LTE heterogeneous networks are merged, the system will be extremely complicated. In the system analysis, the link performance notification can simplify the physical layer model of the wireless communication system, greatly reducing the complexity of system analysis and simulation.

Currently, two popular link performance sensing algorithms are: SNR (exponential effective SNR mapping) algorithm based on signal to noise ratio (SNR), and block average based on information theory. RBIR, received block mean mutual information rate algorithm. For the case of 802.11n and LTE heterogeneous network convergence, the two algorithms do not achieve the same effect. Ideally, the RBIR algorithm predicts insufficient PER accuracy, and the EESM algorithm has poor real-time performance and high complexity.

Summary of the invention

The problem to be solved by the present invention is: The system in which the WLAN and the LTE heterogeneous network are integrated is extremely complicated, especially

802.11η and LTE heterogeneous network convergence, in the system analysis, the use of link performance notification can simplify the physical layer model of the wireless communication system, greatly reducing the complexity of system analysis and simulation, but for WLAN and LTE heterogeneous network convergence In the case of the existing sensing methods, the results are not very satisfactory.

The technical solution of the present invention is: a performance sensing method based on WLAN and LTE heterogeneous network convergence link, comprising the following steps:

1) For the heterogeneous network convergence, determine the selected wireless network, which is a wireless local area network WLAN or a long-term evolution LTE;

2) corresponding to the selected wireless network, determine the corresponding modulation and coding mode MCS;

3) generating real-time channel information, and according to the modulation coding mode determined in step 2), the MCS configures the physical layer parameters, and the code block is modulated and transmitted;

4) The receiving end obtains the average real-time block mutual information MI of the code block from the real-time channel information and the physical layer parameter, and the average real-time block mutual information M1 is a channel quality description that carries the code block at the time under the wireless communication system;

5) Simulation of the wireless network communication system to obtain the block error rate of the block error PER;

6) After abstract fitting, establish a mapping relationship between the average real-time block mutual information M1 and the error packet rate PER through the function model, and then change the real-time channel information, and repeat steps 3) to 5) to obtain Ml and PER under other types of channels. Get the mapping function of Ml and PER:

PER = f _NET , Msc ( ^MI , «n « ₂ ) =

When the selected wireless network NET and the modulation and coding mode MSC are determined, the corresponding function parameter ⁰ ^, ^a can be determined to determine the function of the error rate PER and the average real-time block mutual information MI, thereby realizing the perception of the performance of any link. .

In step 4), the mutual information MI of the code block is obtained from the output signal dry-noise ratio SNR look-up table of the code block, and then averaged to obtain the average real-time block mutual information MI. In step 5), the packet error rate PER = 1-] - BLEI^ BLER represents the block error rate, and N _B represents the number of coded code blocks in one coded modulation packet. The invention has the beneficial effects that the link performance sensing method of the present invention can be applied to the air interface model of WLAN and LTE convergence, which simplifies the physical layer link performance sensing model of the wireless communication system, and performs the mapping relationship between the PER and the average MI. Simple and accurate link performance awareness can accurately estimate the link performance of WLAN and LTE in real time. The simulation proves that the algorithm has high robustness and stability, is applicable to all physical layer configuration transmission schemes, and establishes a universal and simple, and can provide accurate links for WLAN and LTE joint optimization access. Performance-aware approach. DRAWINGS

FIG. 1 is an abstract schematic diagram of a link performance sensing model of the present invention.

Figure 2 shows the WLAN physical layer link model, and IDFT is an inverse discrete Fourier transform.

Figure 3 shows the LTE physical layer link model.

Figure 4 is a map of average real-time block mutual information M1 and signal-to-noise ratio SNR.

FIG. 5 is a simulation result of the physical layer abstraction algorithm of the 802.11n network M1 in the SISO case of the present invention. FIG. 6 is a simulation result of an M1 physical layer abstraction algorithm of an 802.11n network in the MIMO case according to the present invention. FIG. 7 is a simulation result of the physical layer abstraction algorithm of the LTE network M1 in the SISO case of the present invention.

FIG. 8 is a simulation result of the M1 physical layer abstraction algorithm of the LTE network in the MIMO case according to the present invention.

detailed description

The method of the present invention is applied to an air interface model for heterogeneous network convergence of WLAN and LTE, and includes the following steps:

2) corresponding to the selected wireless network, determining a corresponding modulation and coding mode MCS;

5) Simulation of the wireless network communication system to obtain the packet error rate of the block error PER;

6) After abstract fitting, establish the mapping relationship between the average real-time block mutual information M1 and the error packet rate PER through the function model, and then change the real-time channel information, repeat steps 3) - 5), and obtain the channels under other types of channels. MI and PER, get the mapping function between MI and PER:

„„„ „ ,

P ^ER = INETMSC ( ^MI , « « ₂ ) =

When the selected wireless network NET and the modulation and coding mode are determined, the corresponding function parameters ⁰ ^, ^a can be determined to determine the function of the error packet rate PER and the average real-time block mutual information MI, thereby realizing the perception of the performance of any link.

In step 4), the mutual information MI of the code block is obtained from the output signal dry-noise ratio SNR look-up table of the code block, and then averaged to obtain the average real-time block mutual information MI. In step 5), the packet error rate = 1 - ] - ), BLER represents the block error rate, and N _B represents the number of coded code blocks in a coded modulated packet.

The implementation of the technical solution of the present invention will be further described in detail below with reference to the accompanying drawings:

1 is an abstract schematic diagram of a link performance sensing model in a wireless communication system according to the present invention. The packet data is actually the packet format specified by the wireless communication protocol, where WLAN and LTE are different, but this has no effect on the method of the present invention itself. The coded modulation adopts different modulation coding methods according to different physical layer configurations. The physical channel mapping is based on the channel parameter representation of the OFDM system. For both WLAN and LTE, they are based on OFDM modulation and are therefore applicable. What the method of the present invention does is to abstract the modules in the box and establish an equivalent SNR to PER mapping relationship. The packet data in the figure is in PER. The code modulation is used in the LTE and WLAN physical layer protocols: binary phase shift keying BPSK, quadrature phase shift keying QPSK, hexadecimal quadrature amplitude modulation 16QAM, hexadecimal positive The amplitude modulation 64QAM,

(Si , S ₂ S _N ) is a constellation symbol after channel coding and the code block is modulated.

((H!,m ) , ( H ₂ ,n ₂ ) ),...,( H _N ,n _N ) ) are subchannel coefficients and white noise in an OFDM system. For the method of the present invention, there is no need to care about the specific channel coding and detection decoding structure, as well as the details of the physical layer protocol, that is, these details can be masked.

Figure 2 shows the existing WLAN physical layer link model. IDFT is an inverse discrete Fourier transform, showing the baseband transmit end block diagram of WLAN (802.1 In).

Figure 3 shows the existing LTE physical layer link model, showing the baseband transmit end block diagram of LTE.

The simulation platform is built to verify the implementation of the present invention, and the link level simulation platform is constructed according to the architecture of FIG. 2 and FIG. For the signal transmission model of linear detection, when the output signal to noise ratio of the code block is determined, the code block M1 can be uniquely determined, that is, M1 is a determining function of the SNR. Through simulation, the relationship between M1 and SNR can be obtained. For BPSK, QPSK, 16QAM, 64QAM, the mapping between SNR and MI is shown in Figure 4.

For WLAN and LTE, the code block is set to be coded and then modulated, and then sent to the channel. For each subcarrier, the code block MI is obtained from the SNR lookup table, and then averaged to obtain the average MI. The average M1 is under the system. At that time, the channel quality description of the data block is carried, that is, the abstract process is completed. Then, the packet error rate PER under these conditions is obtained by abstracting the parameters of the wireless channel and different modulation and coding modes MCS. After multiple code block simulations, the mapping relationship between the channel sampling points and the average M1 and PER is obtained. Then change the channel parameters and repeat the above process to obtain the PER of the channel sampling points of other parameters in the WLAN and LTE heterogeneous network convergence. The obtained MI data and PER data are summarized to obtain a mapping function of M1 and PER:

The function describes the mapping law of MI and PER in the wireless network, and the accuracy is very high. The average real-time block mutual information M1 is the channel quality description of the code block at the time of the wireless communication system, and the PER reflects the transmission of the code block transmission. Quality, the relationship between the two is used for link performance awareness of heterogeneous network convergence. As shown in Figure 5-8, the functional relationship between PER and Ml is shown, and ⁰ ^ and ⁰ 3⁄4 specific parameter values are obtained, as shown in Table 1 and Table 2, selected communication network type and code modulation. After the MCS mode, the function of PER and Ml can be determined. In Fig. 5 and Fig. 6, the code modulation mode is BPSK 1/2, QPSK 1/2, QPSK 3/4, 16QAM 1/2, 16QAM 3/4, 64QAM 2/3, 64QAM 3/4 from left to right. 64QAM 5/6; In Figures 7 and 8, from left to right are MCS0, MCS3, MCS6, MCS9, MCS10, MCS12, MCS14, MCS 16, MCS 17, MCS19, MCS21, MCS23, MCS25, MCS27.

Table 1. LTE cellular mobile communication network

MCS 10 1.4639 0.0916 1.4882 0.0621

MCS 12 1.6514 0.0812 1.6847 0.0571

MCS 14 1.9902 0.0768 2.0869 0.0589

MCS 16 2.2519 0.0721 2.3409 0.0580

MCS 17 2.5804 0.1228 2.7309 0.1025

MCS 19 2.8567 0.0855 3.1148 0.0843

MCS 21 3.3048 0.0854 3.4168 0.0705

MCS 23 3.6557 0.0825 3.8189 0.0665

MCS 25 4.1605 0.0791 4.3927 0.0859

MCS 27 4.3942 0.0782 4.6141 0.0779 MCS n in Table 1 (n=0,2,6,9,10,12,14,16,17,19,21,23,25,27), 旨 LTE cellular mobile communication The network selectable modulation and coding mode has specific detailed provisions in the 3GPP2 LTE physical layer protocol.

Table 2. 802.11η WLAN

The MCS n (n=0, l, 2, 3, 4...13, 14, 15) in Table 2 refers to the optional modulation and coding mode of the 802.11n WLAN, which is in the IEEE 802.11 η physical layer protocol. Specific detailed regulations.

Claims

Claim

A link performance sensing method based on WLAN and LTE heterogeneous network convergence, which is characterized by the following steps:

1) For heterogeneous network convergence, determine the selected wireless network, which is wireless LAN WLAN or long-term evolution LTE;

3) generating real-time channel information, and according to the modulation coding mode determined in step 2), the MCS configures physical layer parameters, and codes the code block to be modulated and then transmitted;

4) The receiving end obtains the average real-time block mutual information MI of the code block from the real-time channel information and the physical layer parameter, and the average real-time block mutual information M1 is the channel quality description of the current communication block under the wireless communication system;

6) After abstract fitting, establish a mapping relationship between the average real-time block mutual information M1 and the error packet rate PER through the function model, and then change the real-time channel information, and repeat steps 3) to 5) to obtain Ml and PER under other types of channels. Get the mapping function between MI and PER: PER = f _NE TMsc ( ^MI , «i ' « ₂ ) =

When the selected wireless network NET and the modulation and coding mode MSC are determined, the corresponding function parameters can be determined.

" ^a thus determines the function of the packet error rate PER and the average real-time block mutual information MI to achieve the perception of any link performance.

2 . The link performance sensing method for WLAN and LTE heterogeneous network convergence according to claim 1 , wherein in step 4), the code block is obtained from the output signal dry noise ratio SNR table of the code block. The information MI is then averaged to obtain an average real-time block mutual information MI.

The link performance sensing method for WLAN and LTE heterogeneous network convergence according to claim 1 or 2, wherein in step 5)

SLER represents the block error rate, and N _B represents the number of coded code blocks in a coded modulated packet.