TWI405441B - Setting method and apparatus for a wireless communication system - Google Patents

Abstract

A method, for determining a first amount of a plurality of high-throughput long training fields within a packet in a wireless communication system, includes determining a second amount of a plurality of space time streams needed by the wireless communication system transmitting the packet, and setting the first amount to be greater than or equal to 8 when the second amount is greater than 4.

Description

Setting method and setting device for wireless communication system

The present invention relates to a setting method and setting device for a wireless communication system, and more particularly to a setting method and setting device for ensuring an ultra-high throughput wireless area network channel estimation operation.

Wireless Local Area Network (WLAN) technology is one of the popular wireless communication technologies. It was first used in military applications and has been widely used in various consumer electronic products in recent years, such as desktop computers, notebook computers or individuals. Digital assistants provide the convenience and speed of Internet communication for the general public. The IEEE 802.11 series of wireless LAN protocols is developed by the Institute of Electrical and Electronics Engineers (IEEE) and evolved from the early IEEE 802.11a, IEEE 802.11b, and IEEE 802.11g to the current mainstream. IEEE 802.11n. The IEEE 802.11a/g/n standard uses Orthogonal Frequency-Division Multiplexing (OFDM) modulation technology. Unlike the IEEE 802.11a/g standard, the IEEE 802.11n standard uses multiple-input multiple-output ( Multiple Input Multiple Output (MIMO) technology and other new features have greatly improved data rate and throughput (Throughput), while increasing the channel bandwidth from 20MHz to 40MHz.

Please refer to FIG. 1 , which is a schematic diagram of a packet format of the conventional IEEE 802.11n standard. As shown in FIG. 1, the IEEE 802.11n standard packet is composed of a pre-data (Preamble) and a data to be transmitted. The pre-data is located at the forefront of each packet and is connected to the data to be transmitted. In addition, the pre-data is a mixed format, which can be compatible with the IEEE 802.11a/g standard wireless local area network device, and the fields included are the traditional short training field L-STF (Legacy Short Training Field). Traditional long training field L-LTF (Legacy Long Training Field), traditional signal field L-SIG (Legacy Signal Field), high-throughput signal field HT-SIG (High-Throughput Signal Field), high throughput short The training field HT-STF (High-Throughput Short Training Field) and the N high-through-long training field HT-LTF (High-Throughput Long Training Field). The traditional short training field L-STF is used for Start-of-packet Detection, Automatic Gain Control (AGC), Frequency Offset Estimation and Initial Time Synchronization. (Time Synchronization); the traditional long training field L-LTF is used for precise frequency offset estimation and time synchronization; the traditional signal field L-SIG carries information on data rate and packet length. High-throughput signal field HT-SIG carries information on data rate and is used to automatically detect packets in mixed or traditional formats; high-throughput short training field HT-STF for automatic gain control; and high throughput The training field HT-LTF is used for multi-input and multi-output channel estimation, so that the receiving end can judge the channel status.

The high-throughput long training field HT-LTF is well known in the industry and will not be described here. According to its function, the high throughput long training field HT-LTF can be further divided into two categories. The first type is the data high-throughput long training field, which is used to estimate the status of the channel used by the current (data). The number of N _DLTFs is determined by the number of Space Time Streams (N _STS ), such as Figure 2 shows. The second type is the Extension high throughput long training field, which is used to detect the spatial dimension of the unused channel. The number of N _ELTFs is the number of additional spatial dimensions to be detected. N _ESS Determined, and the relationship between the two is the same as the relationship between the number N _DLTF and the number N _STS shown in FIG. 2 . In addition, since the IEEE 802.11n standard supports up to four antennas, both N _DLTF and N _{ELTF are} less than or equal to four.

On the other hand, in order to reduce the complexity of channel estimation, the prior art technique is to design the high throughput long training field HT-LTF to be given different weights and delays by a single symbol (Symbol). Therefore, as shown in Figure 3, for different transmission paths (TX1~TX4), the transmission end will pass the high-throughput long training field HT-LTF through a Spreading Code matrix to determine the appropriate channel estimation. Weight; then Cyclic Shift Delay (CSD) processing, adding Cyclic Prefix to resist multipath transmission channel interference; then through spatial mapping processing, such as beamforming (Beamforming) To improve the signal-to-noise ratio; finally, through the inverse discrete Fourier transform (Inverse Discrete Fourier Transform), to achieve orthogonal frequency division multiplexing modulation, the frequency domain (Frequency Domain) input sequence is converted to the time domain (Time Domain) positive Cross-frequency multiplex symbol (OFDM Symbol) sequence. Wherein, the extension code matrix is a 4×4 matrix P _4×4 , and the details are:

In order to achieve higher quality wireless LAN transmission, the relevant units are developing a new generation of wireless LAN standards, such as IEEE 802.11ac, which has Very High Throughput (VHT) and channel bandwidth from 40MHz. Increased to 80MHz, it can support more than four antennas. In other words, the number of spatial time beams, N _STS (or the number of additional spatial dimensions to be detected, N _ESS ) may exceed 4, which is beyond the situation defined in Figure 2, and cannot determine the high throughput and long training fields of the data. The number N _DLTF (or the number of extended high throughput long training fields N _ELTF ), and the extension code matrix cannot be determined at the same time.

In view of this, it is necessary to determine the number of high-throughput long training fields N _DLTF (or extended height) when the number of spatial time beams N _STS (or the number of additional spatial dimensions to be detected N _ESS ) is greater than 4. The throughput of long training fields (N _ELTF ) to facilitate the implementation of a new generation of wireless LAN standards.

Accordingly, it is a primary object of the present invention to provide a setting method and setting apparatus for a wireless communication system.

The invention discloses a setting method for determining a package in a wireless communication system a first number of the plurality of high throughput long training fields included, the setting method comprising a second quantity determining a plurality of spatial time bundles required by the wireless communication system to transmit the packet; and the second When the number is greater than 4, the first quantity is set to be greater than or equal to 8.

The invention further discloses a setting device for determining a first quantity of a plurality of high-throughput long training fields included in a packet in a wireless communication system, the setting device comprising a microprocessor; and a memory, For storing a program, the program is used to instruct the microprocessor to perform the following steps: determining a second quantity of a plurality of spatial time bundles required by the wireless communication system to transmit the packet; and when the second quantity is greater than 4 The first quantity is set to be greater than or equal to 8.

Please refer to FIG. 4, which is a schematic diagram of a setting process 40 according to an embodiment of the present invention. The setting process 40 is used in a wireless communication system to determine the number of high throughput long training fields included in a packet. The wireless communication system preferably conforms to the wireless local area network standard IEEE 802.11. The setting process 40 includes the following steps:

Step 400: Start.

Step 402: Determine the number of spatial time bundles N _STS required by the wireless communication system to transmit a packet.

Step 404: When the number N _{STS is} greater than 4, the number of high throughput long training fields included in the packet is set to be greater than or equal to 8.

Step 406: End.

According to the setting flow 40, when the number of spatial time beams N _{STS is} greater than 4, the present invention sets the number of high throughput long training fields to 8 or more. In more detail, the high throughput long training field referred to herein is a data high throughput long training field. In other words, the foregoing relationship can be expressed by the following formula:

After the number of data high throughput long training fields N _{DLTF is} determined, the extension code matrix can be further determined to determine the appropriate weight for channel estimation. It should be noted that the extension code matrix is used to convert the high throughput long training field to set the weight of the channel estimation, so the details may be different depending on the system requirements. In general, in order to reduce the computational complexity, each element of the extended code matrix may be preferably set to 1 or -1, and the transposed matrix of the extended code matrix is designed to be equal to the inverse matrix; As long as the row and column of the extension code matrix are interchanged, the inverse matrix can be obtained, which reduces the overall computational complexity. In this way, the results of the above formula can be obtained through the powerful computing power of the computer system.

Further, the relationship between the number N _DLTF and the number N _{STS in} FIG. 2 can be expanded to the example of FIG. 5 , that is, when the number of spatial time beams N _STS is 5, 6, 7, and 8, the data throughput is long. The number of training fields N _{DLTF is} 8. In addition, considering the technical continuity, when designing the extension code matrix applicable to N _DLTF ≧8, the extension code matrix P _4×4 originally applicable to N _DLTF = 4 can be utilized. E.g:

If the extension code matrix Pa _{8×8 is} divided into four 4×4 matrices, such as It can be seen that the upper left 4×4 matrix ( P 11) and the upper right 4×4 matrix ( P 12) are all the extension code matrix P _4×4 . Further, linear operations can be performed on the lower left 4×4 matrix ( P 21) and the lower right 4×4 matrix ( P 22) of the matrix, which can be obtained as: The upper left 4×4 matrix, the upper right 4×4 matrix, and the lower left 4×4 matrix of the extension code matrix Pb _8×8 are all the extension code matrix P _4×4 .

It should be noted that the two embodiments of the extension code matrix Pa _8×8 and Pb _8×8 are 8×8 extension code matrix, but are not limited thereto. At the same time, the spirit of the invention is to determine the number of high throughput long training fields. When the number of high-throughput long training fields is determined, the dimension of the corresponding extended code matrix can be determined, and those skilled in the art can further obtain an appropriate extended code matrix according to different needs.

In order to verify the above method, the simulation result as shown in Fig. 6 can be obtained through an appropriate simulation method to indicate the channel estimation result of a 6-to-2 transmission system. Wherein, the x-axis represents the signal to noise ratio SNR, and the y-axis represents the mean square error MSE (Mean Square Error).

The invention sets the number N _{DLTF of the} data high throughput long training field to be 8 or more when the number of spatial time beams N _{STS is} greater than 4, which can be derived as "the number of additional spatial dimensions to be detected N _ESS When it is greater than 4, the number of extended high-throughput long training fields N _{ELTF is} set to be 8 or more. Such derivation should be easily accomplished by those _{skilled in} the art.

On the other hand, in terms of hardware implementation, the setting process 40 can be converted into a program by software, firmware, etc., and stored in a memory of the wireless communication device to instruct the micro-processing to perform the setting process 40. Such conversion of the set process 40 into a suitable program to implement the corresponding setting means should be a skill familiar to those of ordinary skill in the art.

As mentioned above, the prior art only defines the number of spatial time beams N _STS (or the number of additional spatial dimensions to be detected N _ESS ) is less than or equal to 4 when the number of data high throughput long training fields N _DLTF ( Or extend the number of high throughput long training fields N _ELTF ). Therefore, when the number of spatial time beams N _{STS is} greater than 4, the conventional technique cannot determine the number of high-throughput long training fields, nor can it extend the code matrix. In contrast, the present invention sets the number N _{DLTF of the} data high throughput long training field to be 8 or more when the number of spatial time beams N _{STS is} greater than 4, or more precisely, when the number of spatial time beams N _{When the STS} is equal to 5, 6, 7, or 8, the number of data high throughput long training fields N _{DLTF is} set to 8; thus, the extension code matrix can be further determined.

In summary, the present invention sets the number of data high throughput long training fields to 8 or more when the number of spatial time beams is greater than 4, to ensure the channel estimation operation of the ultra high throughput wireless local area network. .

The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention.

L-STF‧‧‧Traditional Short Training Field

L-LTF‧‧‧Traditional Long Training Field

L-SIG‧‧‧ Traditional Signal Field

HT-SIG‧‧‧High Throughput Signal Field

HT-STF‧‧‧High throughput short training field

HT-LTF‧‧‧High Throughput Training Field

N _STS ‧‧‧Number of space time bundles

N _{DLTF ‧‧‧Number of} data high throughput long training fields

TX1~TX4‧‧‧ transmission path

40‧‧‧Setting process

400, 402, 404, 406‧ ‧ steps

MSE‧‧‧ mean square error

SNR‧‧‧ News ratio

Figure 1 is a schematic diagram of a packet format of the conventional IEEE 802.11n standard.

Figure 2 is a diagram showing the number of high throughput long training fields of the conventional IEEE 802.11n standard.

Figure 3 is a schematic diagram of the processing flow of the conventional IEEE 802.11n standard high throughput long training field.

FIG. 4 is a schematic diagram of a setting process according to an embodiment of the present invention.

FIG. 5 is a schematic diagram showing the number of high throughput long training fields according to an embodiment of the present invention.

FIG. 6 is a schematic diagram of channel estimation results according to an embodiment of the present invention.

40‧‧‧Setting process

400, 402, 404, 406‧ ‧ steps

Claims (16)

A setting method for determining a first quantity of a plurality of data high-throughput long training fields included in a packet in a wireless communication system, the setting method comprising: determining that the wireless communication system needs to transmit the packet a second number of the plurality of spatial time bundles; and when the second number is greater than 4, the first number is set to be greater than or equal to 8. The setting method of claim 1, wherein when the second quantity is greater than 4, the step of setting the first quantity to be greater than or equal to 8 includes when the second quantity is equal to any integer of 5 to 8. , the first quantity is set to 8. The setting method of claim 2, further comprising setting an extension code matrix P of the high-throughput long training field used by the wireless communication system to convert the plurality of data: Wherein, P 11 , P 12 , P 21 and P 22 are respectively a 4×4 matrix. The setting method of claim 3, wherein the P11 is the second number less than or equal to 4, the wireless communication system is configured to convert the extension code matrix of one of the plurality of data high throughput long training fields. The setting method according to claim 4, wherein ;as well as The setting method according to claim 4, wherein ;as well as The setting method according to claim 4, wherein P 21 and P 22 can perform linear operations in units of columns at the same time. A setting device for determining a first quantity of a plurality of data high throughput long training fields included in a packet in a wireless communication system, the setting device comprising: a microprocessor; and a memory for Storing a program for instructing the microprocessor to perform the steps of: determining a second quantity of the plurality of spatial time bundles required by the wireless communication system to transmit the packet; and when the second quantity is greater than 4, The first amount is set to be greater than or equal to 8. The setting device of claim 1, wherein when the second number is greater than 4, the program instructs the microprocessor to perform the step of setting the first quantity to be greater than or equal to 8, including the second quantity being equal to In the case of any integer from 5 to 8, the program instructs the microprocessor to perform the step of setting the first quantity to eight. The setting device of claim 9, wherein the program is further configured to instruct the microprocessor to set an extension code matrix P of the wireless communication system for converting the plurality of data high throughput long training fields: Wherein, P 11 , P 12 , P 21 and P 22 are respectively a 4×4 matrix. The setting device of claim 10, wherein the P11 is the second number less than or equal to 4, the wireless communication system is configured to convert the extension code matrix of one of the plurality of data high throughput long training fields. The setting device of claim 11, wherein ;as well as The setting device of claim 11, wherein ;as well as The setting device according to claim 11, wherein P 21 and P 22 are simultaneously linearly operated in units of columns. A setting method for determining a first quantity of a plurality of extended high throughput long training fields included in a packet in a wireless communication system, the setting method comprising: determining an additional to be detected by the wireless communication system a second quantity of spatial dimensions; and when the second quantity is greater than 4, the first quantity is set to be greater than or equal to 8. A setting device for determining a first quantity of a plurality of extended high throughput long training fields included in a packet in a wireless communication system, the setting device comprising: a microprocessor; and a memory for Storing a program for instructing the microprocessor to perform the steps of: determining a second quantity of the additional spatial dimension of the wireless communication system to be detected; and when the second quantity is greater than 4, A quantity is set to be greater than or equal to 8.