WO2012149847A1

WO2012149847A1 - Radio frame transmitting method and device

Info

Publication number: WO2012149847A1
Application number: PCT/CN2012/073351
Authority: WO
Inventors: 姜静; 张力
Original assignee: 中兴通讯股份有限公司
Priority date: 2011-05-03
Filing date: 2012-03-30
Publication date: 2012-11-08
Also published as: KR101507676B1; BR112013028267B1; KR20130143128A; BR112013028267A2; CN102201891A; CN102201891B; JP5684947B2; JP2014513486A

Abstract

Disclosed is a radio frame transmitting method, for transmitting a null data packet NDP to a receiving end. The null data packet NDP comprises at least two VHT long training fields VHT-LTFs. The maximum number of the VHT long training fields VHT-LTFs is determined by the number of VHT long training fields VHT-LTFs that at least one receiving end can support. Also disclosed is a radio frame transmitting device. Through the solution of the present invention, the number of VHT-LTFs in the null data packet can be more reasonable and can better reflect the characteristics of the receiving end.

Description

Method and device for transmitting wireless frames

The present invention relates to the field of wireless communication technologies, and in particular, to a method and an apparatus for transmitting a wireless frame. Background technique

Wireless Local Area Networks (WLAN) is a network system that uses wireless communication technology to interconnect computer devices to form a network that can communicate with each other and share resources. The essence of WLAN is to replace the connection mode of wired cable by means of wireless connection, realize the wireless interconnection of computer and network, so that the construction of the network and the movement of the terminal are more flexible.

IEEE, Institute for Electrical and Electronic Engineers 802.11 is one of the mainstream technologies for wireless LANs. This protocol mainly specifies the physical layer (PHY) and media access control layer (MAC) specifications. With the development of mobile communication technology and the increasing demand for wireless networks, the physical layer specification has been developing in a direction of increasing speed, going through 801.11 to 802.11b, then to 802.11a/g, then 802.11n, Finally, the development history of 802.11ac. The actual physical technology has also evolved from direct sequence spread spectrum technology to Orthogonal Frequency Division Multiplexing (OFDM) technology, and introduced multi-antenna technology in IEEE802.11n, introducing large bandwidth in IEEE802.il ac. And multi-user Multiple Input Multiple Output (MU-MIMO).

The current IEEE 802.il ac system stipulates that when the receiving end needs to feed back channel information to the transmitting end, the transmitting end sends a feedback request frame (NDPA, Null Data Packet Announcement) and a channel measurement frame (NDP, Null Data Packet) to the receiving end. The STA (equivalent to the receiving end) corresponding to the address (STA) information field in the NDPA feeds back channel information.

The NDP format of the channel measurement frame is as shown in FIG. 1, and includes: a long training sequence (L-STF), Short training sequence (S-STF), signal domain (L-SIG), VHT signal A domain (VHT-SIG-A), VHT short training sequence (VHT-STF), VHT long training domain (VHT-LTF) and VHT Signal B domain (VHT-SIG-B).

There is a lack of a prior art method and apparatus for determining the maximum value of the number of VHT-LTFs in a channel measurement frame NDP. Summary of the invention

The main technical problem to be solved by the present invention is to provide a method and apparatus for transmitting a radio frame, which can determine the maximum number of VHT-LTFs in the VHT long training domain in the channel measurement frame NDP.

To solve the above technical problem, the present invention provides a method for transmitting a radio frame, the method comprising: transmitting a channel measurement frame NDP to a receiving end; the channel measurement frame NDP includes at least two VHT long training domains VHT-LTF, The maximum number of VHT-LTFs in the VHT long training domain is determined according to the number of VHT long training domains VHT-LTF that at least one receiver can support.

Further, the maximum number of VHT-LTFs in the VHT-long training domain is determined according to the number of VHT-long training domains VHT-LTF that can be supported by at least one receiving end, and is: when there is only one receiving end, the maximum number The number of transmitting antennas of the feedback matrix indicated by the capability domain of the receiving end or the channel of the receiving end measures the maximum supportable dimension or the smaller of the two.

Further, the maximum number of VHT-LTFs in the VHT-long training domain is determined according to the number of VHT-long training domains VHT-LTF that can be supported by at least one receiving end, and is: when there are multiple receiving ends, the maximum number The number is the minimum of the number of VHT long training domains VHT-LTF that each receiving end can support.

Further, the method further includes: for each receiving end, the number of VHT long training domains VHT-LTF that can be supported is the number of transmitting antennas of the feedback matrix indicated by the capability domain of the receiving end or the channel measurement of the receiving end is maximum The supported dimensions or the smaller of the two.

Further, the method further includes: setting the number of VHT long training domains VHT-LTF included in the channel measurement frame NDP to be the same as the Nsts indicated in the VHT signal A domain VHT-SIG-A. Further, the channel measurement frame NDP is composed of a long training sequence L-STF, a short training sequence S-STF, a signal domain L-SIG, a VHT signal A domain VHT-SIG-A, a VHT short training sequence VHT-STF, at least two A VHT long training domain consists of VHT-LTF.

A transmitting device for a radio frame, the transmitting device, configured to send a channel measurement frame NDP to a receiving end; the channel measurement frame NDP includes at least two VHT long training domains VHT-LTF, the VHT long training domain VHT- The maximum number of LTFs is determined according to the number of VHT long training domains VHT-LTF that at least one receiver can support.

Further, when there is only one receiving end, the maximum number is the number of transmitting antennas of the feedback matrix indicated by the capability domain of the receiving end or the maximum supported dimension of the channel measurement of the receiving end or the smaller of the two.

Further, when there are multiple receiving ends, the maximum number is the minimum of the number of VHT long training domains VHT-LTF that each receiving end can support; for each receiving end, the VHT that it can support The number of long training domain VHT-LTF is the number of transmitting antennas of the feedback matrix indicated by the capability domain of the receiving end or the maximum supported dimension of the channel measurement of the receiving end or the smaller of the two.

Further, the channel measurement frame NDP is composed of a long training sequence L-STF, a short training sequence S-STF, a signal domain L-SIG, a VHT signal A domain VHT-SIG-A, a VHT short training sequence VHT-STF, at least two A VHT long training domain consists of VHT-LTF.

The beneficial effects of the present invention are: In the method and apparatus for transmitting a radio frame according to the present invention, the maximum number of VHT-LTFs in the transmitted channel measurement frame is determined by the number of VHT long training domains VHT-LTF that the receiving end can support. Therefore, the number of VHT-LTFs in the channel measurement frame is more reasonable, and the characteristics of the receiving end are more reflected.

In the method and apparatus for transmitting a radio frame according to the present invention, the channel measurement frame NDP is composed of a long training sequence (L-STF), a short training sequence (S-STF), a signal domain (L-SIG), and a VHT signal A domain (VHT- SIG-A), VHT short training sequence (VHT-STF), at least two VHT long training domains (VHT-LTF) composition. Compared to the prior art, the channel measurement frame in the method and apparatus of the present invention lacks the VHT signal B field (VHT-SIG-B), thereby reducing the transmission channel measurement frame when transmitting the channel measurement frame NDP to the receiving end. The pilot overhead of NDP. DRAWINGS

1 is a structure of a channel measurement frame NDP in the prior art;

2 is a diagram showing the structure of a channel measurement frame NDP in an embodiment of the present invention. detailed description

The present invention will be further described in detail below with reference to the accompanying drawings.

As shown in Figure 1, the channel measurement frame NDP in the protocol consists of L-STF, S-STF (short training sequence), L-SIG (signal domain), VHT-SIG-A (VHT signal A domain), VHT-STF. (VHT short training sequence;), VHT-LTF (VHT long training domain) and VHT-SIG-B (VHT signal B domain).

To save the pilot overhead, as shown in FIG. 2, the present invention provides a method and apparatus for transmitting a radio frame, which is used to send a channel measurement frame NDP to a receiving end. In the transmission method and apparatus of the present invention, a new channel measurement frame NDP frame structure is employed. The channel measurement frame NDP consists of a long training sequence (L-STF), a short training sequence (S-STF), a signal domain (L-SIG), a VHT signal A domain (VHT-SIG-A), and a VHT short training sequence (VHT). -STF), consisting of at least two VHT long training domains (VHT-LTF).

It can be seen that a major difference between the frame structure of the present invention and the prior art is that VHT-SIG-B (VHT signal B field) is omitted. The existing VHT-SIG-B (VHT signal B domain) includes the following four parts, namely: data length (Length), data modulation coding order (MCS), reserved bits (Reserved), and tail bits (Tail). . The data length Length is defined by the NDP transmission parameter vector table in the protocol, and the data length is limited to 0 in the NDP transmission parameter vector table. For the modulation coding order MCS of the data, the reserved bit and the tail bit Tail, the present invention is designed to be indicated in the VHT signal A field. The table below shows the VHT-SIG-A indication

It can be seen that the content of VHT-SIG-B (VHT signal B field) has been indicated in the transmit parameter vector table TXVECTOR and VHT signal A fields. Therefore, in the present invention, the original function of the VHT-SIG-B (VHT signal B domain) can be guaranteed, and the pilot overhead required for transmitting the NDP can be reduced, thereby performing channel measurement using the NDP of the present invention. Can increase the data transfer rate.

Regardless of the structure of the existing channel measurement frame NDP or the structure of the channel measurement frame NDP proposed in the present invention, both have a VHT long training domain (VHT-LTF). The transmitting method and apparatus of the present invention also sets the maximum number of VHT long training fields before transmitting the channel measurement frame NDP:

The maximum number of VHT long training domains (VHT-LTF) included in the channel measurement frame NDP is determined according to the number of VHT long training domains (VHT-LTF) that at least one receiver can support.

When there is only one receiving end, the maximum value is the number of transmitting antennas of the feedback matrix indicated by the capability domain of the receiving end or the maximum supported dimension of the channel measurement of the receiving end or the smaller of the two. For example, if the receiving end has only the station STA1, the number of transmitting antennas of the feedback matrix indicated by the capability field of the station STA1 is 4, and the maximum supported dimension of the channel measurement of the station is 8, and the maximum number of VHT-LTFs is set. A small value between 4 or 8 or two.

When there are two or more receivers, the threshold is the minimum of the number of VHT-LTFs that each receiver can support. For each receiving end, the number of VHT-long training domains VHT-LTF that can be supported is the number of transmitting antennas of the feedback matrix indicated by the capability domain of the receiving end or the maximum supported dimension of the channel measurement of the receiving end or two of Smaller value.

For example, the receiving end is two stations, which are STA1 and STA2 respectively. The number of VHT-LTFs that N1 can support simultaneously measuring is 4, and the number of VHT-LTFs that STA2 can support for measuring NDP is 8, then NDP The threshold of the VHT-LTF is 4.

When there are multiple receiving ends, the maximum value of the number of VHT-LTFs in the NDP due to the transmitted channel measurement frame is the minimum value among the number of VHT-LTFs that can be supported by each receiving end. That is, there is no case where the number of VHT-LTFs transmitted exceeds the number of VHT-LTFs that can be supported by a certain receiving end. If the maximum number is not set, it may happen that the number of VHT-LTFs sent is eight, and the number of VHT-LTFs that can be supported by one receiver is only four, which causes waste of transmission. , increased the overhead of the pilot. On the other hand, an additional algorithm is needed to process the extra four VHT-LTFs, thereby increasing the complexity of the transmission method and apparatus.

After setting the threshold value, if the threshold value is not exceeded, the VHT long training domain (VHT-LTF) number and the VHT signal A domain (VHT-SIG) included in the channel measurement frame NDP are set. The Nsts indicated in -A ) are the same. It is to be understood that the specific embodiments of the invention are limited only by the description. It is to be understood by those skilled in the art that the present invention may be practiced without departing from the spirit and scope of the invention.

Claims

Claim

A method for transmitting a radio frame, the method comprising: transmitting a channel measurement frame NDP to a receiving end; the channel measurement frame NDP comprising at least two VHT long training domains VHT-LTF, the VHT long training The maximum number of domain VHT-LTFs is determined according to the number of VHT long training domains VHT-LTF that at least one receiver can support.

2. The transmitting method according to claim 1, wherein the maximum number of VHT-LTFs in the VHT long training domain is determined according to the number of VHT-long training domains VHT-LTF that can be supported by at least one receiving end, When there is only one receiving end, the maximum number is the number of transmitting antennas of the feedback matrix indicated by the capability domain of the receiving end or the maximum supported dimension of the channel measurement of the receiving end or the smaller of the two.

The transmission method according to claim 1, wherein the maximum number of VHT-LTFs in the VHT long training domain is determined according to the number of VHT-long training domains VHT-LTF that can be supported by at least one receiver. When there are multiple receiving ends, the maximum number is the minimum of the number of VHT long training domains VHT-LTF that each receiving end can support.

The method of claim 3, wherein the method further comprises: for each receiving end, the number of VHT long training domains VHT-LTF that can be supported by the receiving end is indicated by the capability domain of the receiving end The number of transmit antennas of the feedback matrix or the channel at the receiving end measures the maximum supported dimension or the smaller of the two.

The transmitting method according to any one of claims 1 to 4, further comprising: setting a number of VHT long training domains VHT-LTF and a VHT signal A domain included in the channel measurement frame NDP The Nsts indicated in VHT-SIG-A are the same.

The transmitting method according to any one of claims 1 to 4, wherein the channel measurement frame NDP comprises a long training sequence L-STF, a short training sequence S-STF, a signal domain L-SIG, a VHT The signal A domain VHT-SIG-A, the VHT short training sequence VHT-STF, and at least two VHT long training domains VHT-LTF are composed.

A transmitting device for a radio frame, the transmitting device, configured to send a channel measurement frame NDP to a receiving end, where the channel measurement frame NDP includes at least two VHT long training domains VHT-LTF, The maximum number of VHT-LTFs in the VHT long training domain is determined according to the number of VHT-long training domains VHT-LTF that at least one receiver can support.

The transmitting apparatus according to claim 7, wherein when there is only one receiving end, the maximum number is the number of transmitting antennas of the feedback matrix indicated by the capability domain of the receiving end or the channel measuring of the receiving end is maximum The supported dimensions or the smaller of the two.

The transmitting apparatus according to claim 7, wherein when there are a plurality of receiving ends, the maximum number is the smallest of the number of VHT long training domains VHT-LTF that each receiving end can support. Value; for each receiving end, the number of VHT long training domains VHT-LTF that it can support is the number of transmitting antennas of the feedback matrix indicated by the capability domain of the receiving end or the maximum supported dimension of the channel measurement of the receiving end or two The more '』, the value.

The transmitting apparatus according to any one of claims 7 to 9, wherein the channel measurement frame NDP is composed of a long training sequence L-STF, a short training sequence S-STF, a signal domain L-SIG, and a VHT. The signal A domain VHT-SIG-A, the VHT short training sequence VHT-STF, and at least two VHT long training domains VHT-LTF.