CN105680987A

CN105680987A - Method for realizing link self-adaption and network device

Info

Publication number: CN105680987A
Application number: CN201511030783.9A
Authority: CN
Inventors: 鲍东山; 刘慎发; 于晓燕
Original assignee: Beijing Nufront Mobile Multimedia Technology Co Ltd
Current assignee: Beijing Nufront Mobile Multimedia Technology Co Ltd
Priority date: 2012-03-16
Filing date: 2012-03-16
Publication date: 2016-06-15

Abstract

The invention discloses a method for realizing link self-adaption. The method comprises that a network device sends physical frames with a downlink detection channel and channel quality indication CQI (channel quality information) feedback resource indication to an appointed terminal device; after the terminal device receives the physical frames, the CQI information is fed back to the network device according to allocated resources; and the network device selects a suitable transmission mode for downlink data transmission according to the CQI fed back by the terminal device. The invention also discloses a network device. In adoption of the method and the device provided by the invention, the spectrum use ratio and the system performance can be improved.

Description

Method and network equipment for realizing link adaptation

The invention relates to a method for realizing link adaptation, network equipment and a division of a parent application of terminal equipment, wherein the application date is 3/16/2012 and the application number is 201280012796.1.

Technical Field

The present invention belongs to the field of wireless communication, and in particular, to a method and a network device for implementing link adaptation.

Background

With the rapid development of wireless communication technology, the serious shortage of spectrum resources has increasingly become the "bottleneck" of the development of wireless communication businesses. For a wireless communication system, the most precious is the spectrum resource, so how to fully develop and utilize the limited spectrum resource is critical to improve the use efficiency of the spectrum.

The performance (e.g., throughput) of an actual wireless communication channel, which is a time-varying fading channel, is constantly changing, and conventional designs employ fixed information transmission parameters such as: the channel coding modulation scheme and the transmit power, obviously this cannot accommodate time-varying channels. Therefore, a link adaptation technique is proposed, in which parameters of a transmitter and a receiver, such as transmission power, modulation scheme, coding rate, retransmission times, and data frame length, are dynamically adjusted according to changes of a wireless channel environment in a wireless communication system, so that wireless channel resources are utilized to the maximum extent.

The Channel Quality Information (CQI) indicates channel quality information indicating the estimated size of a transport block, a modulation scheme, the number of parallel codes, and the like that can be received correctly, while ensuring a reasonable block error rate in the downlink or uplink direction. The terminal measures the current wireless receiving environment, estimates the maximum CQI value allowed currently, and the base station selects a proper downlink or uplink channel transmission format according to the CQI suggestion of the terminal, wherein the proper downlink or uplink channel transmission format comprises the size of a transmission block, a modulation mode, the number of parallel codes, a reference power correction value and the like, and the link is adjusted in a self-adaptive manner.

With the rapid development of wireless communication technology, higher requirements are put on methods for implementing link adaptation mechanisms.

Disclosure of Invention

In view of the above, the technical problem underlying the present invention is to provide a new method for implementing link adaptation, and the following presents a simplified summary in order to provide a basic understanding of some aspects of the disclosed embodiments. This summary is not an extensive overview and is intended to neither identify key/critical elements nor delineate the scope of such embodiments. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.

In order to solve the above technical problem, the present invention provides a method for implementing link adaptation, including:

the network equipment configures a downlink detection channel in a system information channel of a physical frame, and distributes resources for Channel Quality Information (CQI) feedback in a control channel;

the network equipment sends the physical frame with the downlink detection channel and the CQI feedback resource indication to the appointed terminal equipment;

after receiving the physical frame, the terminal equipment feeds back CQI information to the network equipment according to the allocated resources;

and the network equipment selects a proper transmission mode for downlink data transmission according to the CQI information fed back by the terminal equipment.

In some optional embodiments, further comprising:

the network equipment sends a CQI feedback request to the terminal equipment; the CQI feedback request is indicated through a control channel of a physical frame, or the CQI feedback request is sent as a sounding frame encapsulated at a MAC layer.

In some optional embodiments, the CQI feedback resource indication comprises an identification ID of the STA and an allocated resource indication; wherein,

the indication of allocated resources comprises one or more of the following information: symbol offset, duration, subchannel mapping and CQI transmission mode; wherein,

the CQI transmission mode includes a modulation and coding scheme MCS and a number of spatial streams indication Nss.

In some optional embodiments, the CQI information is encapsulated into a CQI feedback frame at the MAC layer, including a MAC header, a frame body, and an FCS; and feeding back the CQI information of each sub-channel or feeding back the CQI information of one or two sub-channels with better channels according to the CQI feedback resource indication.

In some optional embodiments, the CQI information is composed of a modulation and coding scheme MCS, a coding type, a signal to interference and noise ratio SINR, and a subchannel mapping, wherein,

a modulation coding scheme MCS for identifying a modulation coding scheme of the requested frequency band; the modulation coding modes are divided into a first modulation coding mode of a request channel code word 1 and a second modulation coding mode of a request channel code word 2;

the coding type is used for identifying a coding mode recommended by the STA;

a signal to interference plus noise ratio, SINR, for identifying the average signal to interference plus noise ratio over the requested bandwidth and spatial stream;

and the sub-channel mapping is used for identifying the bandwidth of the feedback sub-channel and a specific corresponding sub-channel number.

In order to solve the above technical problem, a network device includes:

a configuration unit, configured to configure a downlink probing channel in a control channel of a physical frame, and allocate CQI transmission resources in the control channel;

a sending unit, configured to send the physical frame with the downlink probing channel and the CQI feedback resource indicator to a specified terminal device;

a receiving unit, configured to receive CQI feedback information; and,

and the processing unit is used for selecting a proper transmission mode for downlink data transmission according to the CQI feedback information.

In some optional embodiments, the sending unit is further configured to send a CQI feedback request; the CQI feedback request is indicated through a control channel of a physical frame or is encapsulated at the MAC layer to be transmitted as a sounding frame.

In some optional embodiments, the CQI feedback resource indication comprises an identification ID of the STA and an allocated resource indication, wherein,

the CQI transmission mode further includes the following information: the modulation coding scheme MCS and the number of spatial streams indicate Nss.

the coding type is used for identifying a coding mode recommended by the STA;

a signal to interference plus noise ratio, SINR, for identifying the average signal to interference plus noise ratio over the requested bandwidth and spatial stream; and,

In order to solve the above technical problem, the present invention further provides a method for implementing link adaptation based on channel quality indication feedback, including:

the network equipment sends a physical frame with a downlink detection channel and a Channel Quality Indicator (CQI) feedback resource indicator to the appointed terminal equipment;

after receiving the physical frame, the terminal equipment estimates the channel quality according to the downlink detection channel and feeds back CQI information to the network equipment according to the allocated resources;

and the network equipment receives the CQI information fed back by each terminal equipment and adaptively selects different physical layer transmission parameters for the terminal equipment according to the fed back CQI information.

In some optional embodiments, the network device configures a downlink sounding channel in a system information channel of a physical frame, and configures a CQI feedback resource indication for each terminal device in a control channel of the physical frame.

In some optional embodiments, the CQI feedback resource indication comprises: STA identification, allocated time-frequency resource indication, feedback type and feedback period; the indication of the allocated resources comprises: the channel quality indicator comprises symbol offset, time length, subchannel indication and a CQI transmission mode, wherein the CQI transmission mode comprises modulation coding scheme MCS and spatial stream number indication NSS.

In some optional embodiments, the terminal device calculates a feedback period, and directly feeds back the CQI information to the network device by using the resource indication allocated in the previous period if the feedback period is reached.

In some optional embodiments, the CQI information fed back by the terminal device is encapsulated at the MAC layer to form a channel quality feedback frame, which includes a MAC header, a frame body, and an FCS, where the frame body includes: CQI information for each subchannel.

In some optional embodiments, the CQI information of each subchannel includes: MCS, number of space-time streams, type of coding and signal-to-noise ratio SNR or signal-to-interference-plus-noise ratio SINR.

In some optional embodiments, the CQI information of each subchannel includes: MCS, coding type and signal to noise ratio SNR or signal to interference plus noise ratio SINR.

In order to solve the above technical problem, the present invention further provides a wireless communication system capable of implementing link adaptation based on channel quality indication feedback, including:

and the network equipment is used for sending the physical frame with the downlink detection channel and the CQI feedback resource indication to the appointed terminal equipment.

The terminal equipment is used for estimating the channel quality according to the downlink detection channel after receiving the physical frame and feeding back CQI information to the network equipment according to the allocated resources;

after receiving the CQI fed back by each terminal device, the network device determines its transmission parameters in the subsequent downlink scheduling of the terminal device according to the CQI fed back in combination with the upper layer service information, and sends data to the corresponding terminal device.

In order to solve the above technical problem, the present invention further provides a method for implementing link adaptation based on channel quality indication feedback, comprising the following steps:

the network equipment sends a channel detection frame to the appointed terminal equipment and requires to feed back a CQI message;

after receiving the detection frame, the terminal equipment estimates and calculates the channel quality according to a downlink detection channel, and feeds back CQI information to the network equipment according to the CQI feedback request;

and the network equipment receives the CQI information fed back by each terminal equipment, determines the scheduling of each terminal equipment according to the fed-back CQI information and by combining with the upper layer service information, allocates corresponding physical layer transmission parameters and sends data to the corresponding terminal equipment.

The channel detection frame sent by the network equipment is packaged at an MAC layer, the MAC frame comprises an MAC frame head and a frame body, and the frame body carries information of CQI feedback requests of a plurality of STAs, wherein the information comprises STA identifications, CQI feedback requests and feedback types.

In some optional embodiments, the channel sounding frame is sent in a downlink transmission channel of a physical frame, the network device configures the downlink sounding channel in a system information channel of the physical frame, and indicates a corresponding uplink CQI feedback resource to the terminal device that requires CQI feedback in a control channel of the physical frame.

In some optional embodiments, the CQI feedback resource indication of the terminal device comprises: STA identity and assigned time-frequency resource indication; the allocated time-frequency resource indication comprises: a symbol offset, a duration, and a subchannel indication, and a CQI transmission mode including a Modulation and Coding Scheme (MCS) and a number of spatial streams indication (Nss).

In some optional embodiments, the feedback type is CQI feedback; the CQI information fed back by the terminal equipment is packaged at an MAC layer to form a channel quality feedback frame, which comprises an MAC frame head, a frame body and an FCS, wherein the frame body part comprises: CQI information for subchannels of each operating bandwidth.

In some optional embodiments, the CQI information of the subchannels of each operating bandwidth includes: MCS, Nss, coding type and SNR or SINR.

In some optional embodiments, before feeding back CQI information to the network device according to the CQI feedback request, the method further includes:

in some optional embodiments, the terminal device estimates and calculates the channel quality according to the downlink sounding channel of the physical frame.

the network device is used for sending a channel detection frame to each terminal device in a broadcasting mode and requiring to feed back CQI information, the channel detection frame is packaged at an MAC layer and is transmitted at a downlink transmission channel of a physical frame, the channel detection frame comprises an MAC frame head and a frame body, and the frame body carries CQI feedback requests and feedback types of one or more terminal devices.

After receiving the channel detection frame, the terminal equipment estimates the channel quality according to a downlink detection channel and feeds back CQI information to the terminal equipment at a specified position according to the allocated resources;

sending a downlink detection channel and channel quality information CQI feedback resource indication;

and receiving CQI information, and selecting a proper transmission mode for downlink data transmission according to the CQI information.

In some optional embodiments, the CQI feedback resource indication comprises an identification ID of the STA and an allocated resource indication.

In some optional embodiments, the indication of allocated resources specifically comprises one or more of the following information: symbol offset, duration, subchannel mapping and CQI transmission mode; wherein,

In some optional embodiments, the CQI feedback resource indication includes a feedback period for instructing the terminal device to periodically feed back the CQI information.

In some optional embodiments, further comprising:

and the terminal equipment calculates time according to the feedback cycle, and directly feeds back CQI information once the time reaches the feedback cycle.

In some optional embodiments, further comprising:

and sending a CQI feedback request for indicating the terminal equipment to feed back the CQI information.

In some optional embodiments, the sending the CQI feedback request specifically includes:

and packaging the CQI feedback request into a detection frame at an MAC layer for sending, or indicating the CQI feedback request through a control channel of a physical layer.

In some optional embodiments, further comprising:

and the terminal equipment responds to the CQI feedback request and feeds back CQI information on the feedback resource according to the CQI feedback resource indication.

In some optional embodiments, the CQI information comprises one or more of the following information:

a modulation coding scheme MCS for identifying a modulation coding scheme of the requested frequency band;

the coding type is used for identifying a coding mode recommended by the STA;

a signal-to-noise ratio, SNR, identifying a requested bandwidth and an average signal-to-noise ratio over spatial streams; and,

the coding type is used for identifying a coding mode recommended by the STA;

In some optional embodiments, the modulation and coding scheme is divided into a first modulation and coding scheme and a second modulation and coding scheme.

In order to solve the above technical problem, the present invention further provides a network device, including:

a sending unit, configured to send a downlink sounding channel and a channel quality information CQI feedback resource indication;

a receiving unit configured to receive CQI information; and,

and the processing unit is used for selecting a proper transmission mode for downlink data transmission according to the CQI information.

In some optional embodiments, the sending unit is further configured to send a CQI feedback request, and instruct the terminal device to feed back the CQI information in response to the CQI feedback request.

In some optional embodiments, the sending unit is specifically configured to encapsulate the CQI feedback request as a sounding frame at a MAC layer for sending, or specifically to indicate the CQI feedback request through a control channel of a physical layer.

the coding type is used for identifying a coding mode recommended by the STA;

In order to solve the above technical problem, the present invention further provides a terminal device, including:

a receiving unit, configured to receive a downlink sounding channel and a channel quality information CQI feedback resource indication;

a detection unit, configured to detect the downlink sounding channel and obtain CQI information; and,

and the feedback unit is used for feeding back the CQI information on the feedback resources.

In some optional embodiments, the CQI feedback resource indication includes a feedback period for instructing the terminal device to periodically feed back the CQI information;

and the feedback unit is used for calculating time according to the feedback cycle and directly feeding back the CQI information once the time reaches the feedback cycle.

In some optional embodiments, the receiving unit is further configured to receive a CQI feedback request;

in some optional embodiments, the feedback unit is configured to, in response to the CQI feedback request, instruct feedback of CQI information on a feedback resource according to the CQI feedback resource.

the coding type is used for identifying a coding mode recommended by the STA;

In summary, the technical solution for implementing downlink adaptation provided by the present invention employs a periodic feedback mechanism, which saves signaling overhead, thereby saving system resources; by adopting the request feedback mechanism, the configuration and management of CQI feedback of the CAP to one or more STAs can be realized, the resource configuration is optimized as much as possible, the system efficiency is improved, the overall arrangement of channel resources by the CAP is realized, and the user can further multiplex on space resources, so that the spectrum utilization rate is improved.

For the purposes of the foregoing and related ends, the one or more embodiments include the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative aspects and are indicative of but a few of the various ways in which the principles of the various embodiments may be employed. Other benefits and novel features will become apparent from the following detailed description when considered in conjunction with the drawings and the disclosed embodiments are intended to include all such aspects and their equivalents.

Drawings

Fig. 1 is a flowchart illustrating a method for implementing link adaptation according to an embodiment of the present invention;

fig. 2 is a frame structure diagram of a physical frame configuration of a method for implementing downlink adaptation based on a periodic feedback mechanism according to a second embodiment of the present invention;

fig. 3 is a schematic structural diagram of a channel quality information feedback frame according to a second embodiment of the present invention;

fig. 4 is a schematic structural diagram of a channel quality information feedback frame in a specific scenario according to a second embodiment of the present invention;

fig. 5 is a schematic structural diagram of a channel quality information feedback frame in a specific scenario according to a second embodiment of the present invention;

fig. 6 is a schematic diagram of a frame body part of a channel quality information feedback frame according to a second embodiment of the present invention;

fig. 7 is a schematic diagram of a frame body part of a channel quality feedback frame according to a second embodiment of the present invention;

fig. 8 is a schematic diagram of a frame body part of a channel quality feedback frame according to a second embodiment of the present invention;

fig. 9 is a flowchart illustrating a method for implementing downlink adaptation based on a periodic feedback mechanism according to a second embodiment of the present invention;

fig. 10 is a schematic structural diagram of a network device according to a second embodiment of the present invention;

fig. 11 is a schematic structural diagram of a terminal device according to a second embodiment of the present invention;

fig. 12 is a frame structure diagram of a downlink adaptive physical frame configuration based on a request-response feedback mechanism according to a third embodiment of the present invention;

fig. 13 is a flowchart illustrating a method for implementing downlink adaptation based on a request-response feedback mechanism according to a third embodiment of the present invention;

fig. 14 is a schematic structural diagram of a network device according to a third embodiment of the present invention;

fig. 15 is a schematic structural diagram of a terminal device according to a third embodiment of the present invention;

fig. 16 is a schematic structural diagram of a channel sounding frame carrying a CQI feedback request according to a fourth embodiment of the present invention;

fig. 17 is a frame structure diagram of a downlink adaptive physical frame configuration based on a request-response feedback mechanism according to a fourth embodiment of the present invention.

Detailed Description

The following description and the drawings sufficiently illustrate specific embodiments of the invention to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, and other changes. The examples merely typify possible variations. Individual components and functions are optional unless explicitly required, and the sequence of operations may vary. Portions and features of some embodiments may be included in or substituted for those of others. The scope of embodiments of the invention encompasses the full ambit of the claims, as well as all available equivalents of the claims. Embodiments of the invention may be referred to herein, individually or collectively, by the term "invention" merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept if more than one is in fact disclosed.

In view of the defects in the prior art, the invention provides a method for realizing uplink and downlink self-adaptation, which can improve the utilization rate of frequency spectrum resources and the system performance.

Link adaptation and other mechanisms, such as beamforming and multi-user MU-MIMO are indivisible. Are adaptive techniques that are used to adapt to channel variations and to improve link and system capacity and may share some feedback results or the feedback results calculated by the responding end may need to be considered simultaneously. The invention only considers the link self-adapting realization method based on the channel quality information feedback.

In the following description, network devices such as an access point AP, a central access point CAP, a base station, or other network devices, and terminal devices such as a user station STA, a terminal, or other terminal devices, are all described with reference to the network device as the CAP and the terminal device as the STA, but are not limited to the CAP and the STA.

In the invention, for the medium-short distance wireless communication system, the link self-adaptive mechanism comprises downlink self-adaptation and uplink self-adaptation. Wherein downlink adaptation refers to link adaptation in the direction from the CAP to the STA; uplink adaptation refers to link adaptation in the direction from the STA to the CAP.

1. Downlink adaptation

In a medium-short distance wireless communication system, downlink data transmission supports a link adaptation mechanism. The CAP can adaptively select different physical layer transmission parameters for the STA according to the CQI information fed back by the STA, where the parameters include: MIMO operation mode, number of spatial streams, coding modulation scheme MCS, transmission power, and the like.

The feedback mechanism supported by downlink adaptation includes the following three: periodic feedback mechanisms, request-response based feedback mechanisms, and proactive response feedback mechanisms.

The present invention is described primarily with respect to a periodic feedback mechanism, a request-response based feedback mechanism.

Example one

Referring to fig. 1, an embodiment of the present invention provides a method for implementing downlink adaptation, including the following steps:

step S101, CAP sends down detecting channel and CQI feedback resource indication to each STA.

Step S102, the STA responds to the CQI feedback request and feeds back CQI information on the feedback resource according to the CQI feedback resource indication.

Step s103, the CAP receives the CQI fed back by each STA, and selects an appropriate transmission mode for downlink data transmission according to the fed back CQI.

Example two

Referring to fig. 1, a second embodiment of the present invention provides a method for implementing downlink adaptation, where the method employs a periodic feedback mechanism, and includes the following steps:

Preferably, the downlink sounding channel and the CQI feedback resource indication may be encapsulated in a physical frame for transmission.

Preferably, the CQI feedback resource indication includes a feedback period for instructing the STA to periodically feed back CQI information.

The periodic feedback mechanism is that the CAP periodically allocates resources for the STA to perform uplink channel feedback in the control channel of the physical layer without transmitting a CQI feedback request by the CAP. Therefore, preferably, before step s101, the CAP may be prepared in advance as follows:

the CAP configures a downlink detection channel in a system information channel of a physical frame for sending a downlink detection signal, so that the STA completes downlink channel measurement to obtain CQI information.

The CAP periodically allocates resources for the STA to perform uplink channel feedback in a control channel of a physical frame, and specifically, configures a CQI feedback resource indication in the control channel.

Preferably, the information of the CQI feedback resource indication includes: an identification id (STA id) of each STA and an indication of the allocated resources. The allocated resource indication information specifically includes one or more of the following information: symbol offset, duration, sub-channel mapping and CQI transmission mode, wherein the symbol offset is used for indicating a user resource block to start an OFDM symbol; the duration is used for indicating the number of continuous OFDM symbols of a user resource block; a subchannel map for indicating a CQI feedback subchannel through a BitMap; the CQI transmission mode includes a Modulation and Coding Scheme (MCS) and a number of spatial streams indication (Nss).

Preferably, the CQI feedback resource indication includes: STAID, allocated resource indication, and feedback period.

Preferably, for the periodic resource allocation, in order to save signaling overhead, for the same STA, the CAP may not need to configure the CQI feedback resource indication in the control channel every time, but may notify the STA of the information of the resource allocation, the feedback period, and the like at one time by sending only one physical frame carrying the CQI feedback resource indication, the STA stores the newly received allocated resource indication and the feedback period, and the CAP does not need to carry the CQI feedback resource indication in a plurality of frames sent later. And the STA calculates time, and once the time reaches the feedback period which is newly stored, the CQI feedback resource indication which is newly stored on the feedback resource can be used by default to directly feed back the CQI information to the CAP. For example, as shown in the frame structure diagram of the physical frame configuration shown in fig. 2, in the previous feedback period (physical frame N in fig. 2), the CAP allocates CQI feedback resources and feedback periods to STA1, STA2, and STA3, and when the next feedback period arrives (physical frame N + feedback period in fig. 2), it is possible to calculate time for STA1, STA2, and STA3, and once the feedback period arrives, the CQI information is directly transmitted at the specified position of the uplink subframe by using the aforementioned CQI feedback resource indication without re-allocating CQI feedback resources and feedback periods to STAs by the CAP.

Preferably, the STA receives a downlink probing channel and a CQI feedback resource indication of channel quality information sent by the CAP, detects the downlink probing channel to obtain the CQI, and periodically feeds back the CQI to the network device on the feedback resource according to the CQI feedback resource indication, which specifically includes: and the STA calculates time according to the feedback period, and once the time reaches the feedback period, the CQI information is periodically and directly fed back to the network equipment on the feedback resource according to the CQI feedback resource indication.

Preferably, the CQI information may be encapsulated into a MAC frame to form a channel quality information CQI feedback frame. The CQI feedback frame includes a MAC header, a frame body and an FCS, wherein the frame body part information may feed back CQI information of each operating bandwidth according to the feedback type indication, preferably, as shown in fig. 2, all CQI information on sub-channels 1 to 4 may also be fed back by the STA of CQI information of one or two sub-channels with better channel. Wherein the CQI information may include one or more of the following information: modulation Coding Scheme (MCS), number of space-time streams (Nss), coding type (LDPC/BCC), signal-to-noise ratio (SNR), or signal-to-interference-and-noise ratio (SINR).

Preferably, for example, as shown in fig. 3, the CQI information may include: modulation Coding Scheme (MCS), number of space-time streams (Nss), coding type (LDPC/BCC), and signal-to-noise ratio (SNR) (or signal-to-interference-and-noise ratio (SINR)).

Preferably, as shown in fig. 4, the CQI information may also include MCS, coding type and SNR (or SINR), and the Modulation and Coding Scheme (MCS) may include number of space-time streams (Nss). The MCS is used to identify the modulation and coding scheme of the requested frequency band. The coding type is used for identifying a coding mode recommended by the terminal. The SNR is used to identify the average signal-to-noise ratio on each spatial stream of the requested channel and the SINR is used to identify the average signal or interference-plus-noise ratio on each spatial stream of the requested channel.

Preferably, as shown in fig. 5, the CQI information may further include a subchannel map for identifying the bandwidth of the feedback subchannel and a specific corresponding subchannel number.

Preferably, if the system supports 8 spatial streams and one MCS supports at most 4 spatial streams, two MCSs are required, as shown in fig. 6, the MCSs can be divided into 2, i.e. a first modulation and coding scheme MCS1 indicating the MCS requesting channel codeword 1 and a second modulation and coding scheme MCS2 indicating the MCS requesting channel codeword 2. Preferably, the CQI information may include subchannel mapping, MCS1, MCS2, coding type, and SINR. The contents of the CQI information are shown in table 1:

TABLE 1

When the system operates at 20MHz, the frame body portion of the channel quality feedback frame is as shown in fig. 4 or 5 or 6.

When the system operates in 40MHz aggregation mode 1, the frame body portion of the channel quality feedback frame is shown in fig. 7.

When the system operates in 80MHz aggregation mode 1, the CQI _ FB frame body portion is as shown in fig. 8.

When the system operates in 40MHz aggregation mode 2, the CQI _ FB frame body portion is as shown in fig. 6.

When the 80MHz system operates at 40MHz continuously, the CQI _ FB frame body portion is as shown in fig. 7.

When the system operates at continuous 80MHz, the CQI _ FB frame body portion is as shown in fig. 6.

With respect to the above-mentioned polymerization mode, the following is specifically described:

spectrum aggregation

The part takes 20MHz as basic channel bandwidth, and continuous or discontinuous bandwidths of 40MHz and 80MHz spectrums can be supported through spectrum aggregation.

Polymerization mode 1: each 20MHz sub-channel is an independent channel, and 20MHz, 40MHz, and 80MHz stas can be scheduled to transmit independently on one or more 20MHz sub-channels;

polymerization mode 2: multiple consecutive 20MHz sub-channels are aggregated, and 40MHz and 80MHz stas can continuously transmit in the frequency domain on the aggregated channel.

Only aggregation mode 1 can be selected by 20MHz sta, and aggregation mode 1 or 2 can be selected by 40MHz and 80MHz sta.

Fig. 2 is a frame structure diagram of a physical frame configuration of a method for implementing downlink adaptation based on a periodic feedback mechanism according to a second embodiment of the present invention. As shown in fig. 2, the CAP configures a downlink sounding channel in the system information channel of the physical frame in advance, and allocates resources for CQI transmission to STAs (STA1, STA2, and STA3) requiring channel quality feedback in the control channel of the physical frame, specifically by configuring a CQI feedback resource indication in the control channel. STA1, STA2, and STA3 calculate and estimate channel information according to the downlink sounding channel of the received physical frame, and periodically transmit CQI information at corresponding positions of the uplink subframe of the frame according to the CQI feedback resource indication.

After receiving the CQI information fed back by each STA, the CAP determines scheduling of the service of each STA in combination with upper layer service information including parameters such as service priority, QoS, and the like, determines transmission parameters in subsequent downlink scheduling of STA1, STA2, and STA3 according to the fed back CQI information, and sends data to the corresponding STA.

The method provided by the second embodiment can also be described by using the method of fig. 9. As shown in fig. 9, the method includes:

step S201, CAP configures a downlink detection channel in a system information channel SICH of a physical frame, and allocates resources for CQI feedback in a control channel UL-CCH of the physical frame;

step S202, the STA carries out CQI feedback in an uplink subframe;

step S203, the CAP selects a transmission mode according to the feedback information;

step S204, performing uplink and downlink data transmission between the CAP and the STA;

step S205, the STA calculates time, and once the feedback period is reached, the STA performs CQI feedback in the uplink subframe.

Preferably, after step S204, in order to save signaling overhead, for the same STA, the CAP may not need to configure the CQI feedback resource indication in the control channel every time, but may configure information such as resource allocation and feedback period and notify the STA once through step S201, the STA stores the newly received allocated resource indication and feedback period, and the CAP does not need to carry the CQI feedback resource indication in a plurality of frames sent later. The STA calculates the time, and once the time reaches the latest saved feedback period, the STA may transmit the CQI information directly at the specified position of the uplink subframe by using the latest saved CQI feedback resource indication on the feedback resource by default, step S205.

Preferably, after step S205, the method further includes step a: the CAP selects a transmission mode according to the feedback information; and carrying out uplink and downlink data transmission between the CAP and the STA. Or,

preferably, after step S205, the method further includes step B: and carrying out uplink and downlink data transmission between the CAP and the STA. In this case, the CAP may no longer reselect the transmission mode, but defaults to the configuration of step S203.

Preferably, after step a or B, the steps are repeated: once the feedback period is reached, the STA performs CQI feedback in the uplink subframe.

By analogy … …

Fig. 9 is only described by taking the step S205 as an example, but the process of repeating the step after the step S205 is within the protection scope.

In order to implement the method for implementing link adaptation, a second embodiment of the present invention further provides a network device, as shown in fig. 10, including:

a sending unit 11, configured to send a downlink probing channel and a channel quality information CQI feedback resource indication to a terminal device;

a receiving unit 12, configured to receive CQI information fed back by each terminal device; and,

and the processing unit 13 is configured to select an appropriate transmission mode for downlink data transmission according to the fed back CQI information.

In order to implement the method for implementing link adaptation, a second embodiment of the present invention further provides a terminal device, as shown in fig. 11, including:

a receiving unit 21, configured to receive a downlink sounding channel and a CQI feedback resource indication;

a detecting unit 22, configured to detect a downlink probing channel and obtain CQI information; and,

a feedback unit 23, configured to feedback the CQI information on the feedback resource. Preferably, the CQI information is fed back to the network device periodically on the feedback resources according to the CQI feedback resource indication.

Preferably, the CQI feedback resource indication includes at least the following information: identification of the terminal, an indication of the allocated resources and a feedback period. The feedback unit 23 calculates time according to the feedback cycle, and directly feeds back CQI information if the time reaches the feedback cycle.

In order to implement the method for implementing link adaptation, a second embodiment of the present invention further provides a system for implementing link adaptation, including the network device and the terminal device provided in the second embodiment.

In the system, the network device, and the terminal device for implementing link adaptation provided in the second embodiment of the present invention, the working principle and the related operation flow are substantially the same as those in the foregoing implementation scheme of the method for implementing downlink adaptation based on the periodic feedback mechanism, and are not described herein again.

In summary, by using the periodic feedback mechanism provided in the second embodiment, signaling overhead is saved, so that system resources are saved, thereby improving spectrum utilization, adaptively scheduling spectrum resources, and improving spectrum utilization and system performance.

EXAMPLE III

Referring to fig. 1, a third embodiment of the present invention provides a method for implementing downlink adaptation, which employs a request-response feedback mechanism and mainly includes the following steps:

step S101, CAP sends downlink detection channel and CQI feedback resource indication to each STA;

preferably, before sending the downlink probing channel and the CQI feedback resource indication, a CQI feedback request is also sent; and the CQI feedback request is used for indicating the STA to feed back the CQI information.

Preferably, after the downlink probing channel and the CQI feedback resource indication are sent, a CQI feedback request is also sent.

Preferably, the downlink probing channel and the CQI feedback resource indication are transmitted together with a CQI feedback request.

Preferably, the downlink probing channel, the channel quality information CQI feedback request, and the CQI feedback resource indication may be encapsulated in a physical frame for transmission.

Preferably, the CQI feedback request is indicated through a control channel of a physical frame, as shown in fig. 12.

Preferably, before step s201, the CAP may also be prepared in advance as follows:

the CAP configures a downlink probing channel in the system information channel of the physical frame in advance for sending a downlink probing signal, so that the STA completes the physical channel for downlink channel measurement and obtains CQI information.

The CAP configures a CQI feedback request and a CQI feedback resource indication in the control channel in advance.

Wherein, the system information field is defined as shown in table 2.

TABLE 2

As shown in Table 2, by b₆₄And configuring a downlink detection channel, wherein 0 represents that no downlink detection channel exists, and 1 represents that the downlink detection channel is configured.

The CAP allocates resources for CQI transmission to each STA in the control channel, and specifically, implements this by configuring a CQI feedback resource indication in the control channel. The CQI feedback resource indication specifically includes: symbol offset and duration. The symbol deviation indicates the initial OFDM symbol of the user resource block, the time length indicates the number of continuous OFDM symbols of the user resource block.

The control channel field definition is shown in table 3.

TABLE 3

As shown in Table 3, by b₁₆b₁₅Lb₈Bit indication symbol offset, i.e. user resource block start OFDM symbol, by b₃₂b₃₁Lb₂₄The bit indicates the duration, i.e. the number of consecutive OFDM symbols of the user resource block.

The method for indicating the CQI feedback request through the control channel specifically includes: through b₄₀Indicating a CQI feedback request is made for 1 bit.

Preferably, the request-response based feedback mechanism means that the CAP actively sends a CQI feedback request according to a specific scenario. Once the CAP decides to initiate the CQI feedback request, the CAP indicates the CQI feedback request on a control channel; meanwhile, corresponding CQI transmission resources are allocated to the STAs requiring CQI feedback in the control channel, and the control channel may simultaneously include a plurality of pieces of CQI feedback resource indication information allocated to the STAs, where the information includes indication information such as an identification (STA id) of the STA and an allocated resource indication, where the allocated resource indication specifically includes: symbol offset, duration, and subchannel indication; preferably, the allocated resource indication further includes a CQI transmission mode, wherein the CQI transmission mode specifically includes a Modulation and Coding Scheme (MCS) and a number of spatial streams indication (Nss).

Preferably, the STA detects the downlink sounding channel to obtain the CQI, responds to the CQI feedback request, and feeds back on the feedback resource according to the indication of the CQI feedback request.

Preferably, the feedback resource is a resource designated by the CAP, and the STA feeds back CQI information at the designated resource.

The designated resource means that certain specific OFDM symbols in the uplink transmission channel are designated in the uplink control channel for transmitting the feedback channel information. B in control channel due to CAP₁₆b₁₅Lb₈Bit sum b₃₂b₃₁Lb₂₄And after the initial OFDM symbol of the user resource block and the continuous OFDM symbol number of the user resource block are appointed, the STA feeds back channel information in the appointed resource. Therefore, the feedback resource is allocated to the uplink control channel, and specifically, the feedback resource is realized by indicating the starting OFDM symbol of the user resource block and the number of consecutive OFDM symbols of the user resource block on the uplink control channel.

The detailed description of the fed back CQI information is the same as that in the first embodiment, and is not repeated here.

Preferably, after the CAP receives the CQI information fed back by each STA, the CAP determines scheduling of the service of each STA in combination with upper layer service information including parameters such as service priority and QoS, selects a suitable transmission mode for downlink data transmission, and allocates corresponding physical layer transmission parameters for downlink data transmission.

The method provided by the third embodiment can also be described by adopting the manner of fig. 13. As shown in fig. 13, the method includes the steps of:

step S301, CAP configures a downlink detection channel in SICH and allocates CQI transmission resources in UL-CCH;

step S302, the STA feeds back CQI in the appointed resource;

step S303, CAP selects a proper transmission mode for downlink data transmission according to the CQI feedback.

To implement the above method for implementing link adaptation, a third embodiment of the present invention further provides a network device, as shown in fig. 14, including:

a sending unit 31, configured to send a downlink probing channel and a CQI feedback resource indication to a terminal device;

preferably, the sending unit 31 is further configured to send a CQI feedback request before sending the downlink probing channel and the CQI feedback resource indication; and the CQI feedback request is used for indicating the STA to feed back the CQI information.

Preferably, the sending unit 31 is further configured to send a CQI feedback request after sending the downlink probing channel and the CQI feedback resource indication.

Preferably, the sending unit 31 is further configured to send the CQI feedback request together with the downlink probing channel and the CQI feedback resource indication.

Preferably, the channel quality information CQI feedback request may be sent in a physical frame together with the downlink sounding channel and the CQI feedback resource indication, and the CQI feedback request is indicated by a control channel of the physical frame.

A receiving unit 32, configured to receive CQI information fed back by the terminal device;

and the processing unit 33 is configured to select an appropriate transmission mode for downlink data transmission according to the fed back CQI information.

In order to implement the method for implementing link adaptation, a third embodiment of the present invention further provides a terminal device, as shown in fig. 15, including:

a receiving unit 41, configured to receive a downlink probing channel and a CQI feedback resource indication sent by a network device.

Preferably, the receiving unit 41 is further configured to receive a CQI feedback request.

A detecting unit 42, configured to detect a downlink probing channel and obtain CQI information;

a feedback unit 43, configured to perform feedback to the network device on a feedback resource; preferably, feedback is made to the network device on the feedback resources according to the indication of the CQI feedback request.

In order to implement the method for implementing link adaptation, a third embodiment of the present invention further provides a system for implementing link adaptation, including the network device and the terminal device provided in the third embodiment.

In the system, the network device, and the terminal device for implementing link adaptation provided in the third embodiment of the present invention, the working principle and the related operation flow are substantially the same as those in the foregoing implementation of the method for implementing downlink adaptation under the request-response based feedback mechanism, and are not described herein again.

In summary, by using the request feedback mechanism provided in this embodiment, the configuration and management of CQI feedback for the STA by the CAP can be implemented, so as to optimize resource configuration as much as possible, improve system efficiency, and implement that the CAP can integrally arrange channel resources, so that the user can further multiplex on spatial resources, thereby improving spectrum utilization, adaptively scheduling spectrum resources, and improving spectrum utilization and system performance. In addition, as the CQI feedback request is transmitted firstly on the MAC layer and then the CQI is fed back, the CQI feedback request and the CQI feedback both need the control channel of the physical layer to allocate resources for the CQI feedback request and the CQI feedback, at least two times of interaction is needed; however, in this embodiment, when the control channel of the physical layer allocates resources for CQI feedback, the CQI feedback request is indicated by 1bit, and the function of two interactions at the MAC layer can be realized by one interaction, which not only reduces the system overhead, but also reduces the request feedback delay.

Example four

Referring to fig. 1, another method for implementing downlink adaptation is provided in the fourth embodiment of the present invention, where a request-response feedback mechanism is adopted, and the method mainly includes the following steps:

Preferably, before sending the downlink probing channel and the CQI feedback resource indication, a CQI feedback request is also sent.

Preferably, different from the third embodiment, the CQI feedback request may be encapsulated into a channel sounding frame at the MAC layer and sent on a downlink transport channel at the physical layer, where the channel sounding frame is a MAC frame. The channel sounding frame carries a CQI feedback request; the CQI feedback request is used to request CQI feedback from the STA. The CAP sends a channel sounding frame to each STA in a broadcast manner or a unicast manner, and requires each STA to feed back CQI information. Wherein, if the CAP transmission is a multi-user CQI feedback request, the CQI feedback request includes CQI feedback requests of a plurality of STAs.

Preferably, before step S101, the CAP may be prepared in advance as follows:

the CAP configures a downlink probing channel in a system information channel of a physical layer for sending a downlink probing signal, so that the STA finishes downlink channel measurement and obtains CQI information.

The CAP distributes the resources of CQI transmission for the STA in a control channel for the STA to feed back CQI information; specifically, the CQI feedback resource indication is configured on the control channel. The control channel may simultaneously include a plurality of CQI feedback resource indication information allocated to the STA, where the information includes an identifier of each STA and indication information such as allocated resource indication, and the allocated resource indication information specifically includes: symbol offset and duration. Preferably, the resource indication information allocated may further include: a CQI transmission mode, wherein the CQI transmission mode includes a Modulation and Coding Scheme (MCS) and a number of spatial streams indication (NSS).

Preferably, the channel sounding frame includes a MAC header and a frame body, if the channel sounding frame is broadcast, the CQI feedback request further includes an STA identifier, and when multi-user CQI feedback is requested, the frame body may carry information of CQI feedback requests of multiple STAs, where a frame structure of the channel sounding frame is as shown in fig. 16.

Preferably, the request-response based feedback mechanism means that the CAP actively sends CQI feedback requests to the STAs according to a specific scenario. Once the CAP determines to initiate a CQI feedback resource request, it encapsulates a channel sounding frame carrying the CQI feedback request in the MAC layer, and sends the channel sounding frame in a downlink transmission channel of a physical frame, as shown in fig. 17.

Preferably, after receiving the sounding frame, the STA estimates and calculates the channel quality according to the downlink sounding channel, and feeds back CQI information to the CAP according to the CQI feedback request, and preferably feeds back CQI information to the CAP on the feedback resource according to the CQI feedback resource indication; preferably, in the uplink subframe of the frame, according to the resource indicated by the control information, the CQI information is fed back by using a lower-cost modulation scheme (such as BPSK, QPSK, or single-stream mode), that is, the STA needs to encapsulate the MAC frame to transmit the CQI feedback information.

Preferably, the STA receives the downlink probing channel, the CQI feedback request, and the CQI feedback resource indication, detects the downlink probing channel, that is, estimates and calculates channel quality according to the downlink probing channel, obtains CQI information, responds to the CQI feedback request, and feeds back on the feedback resource according to the CQI feedback request indication.

The detailed description of the fed back CQI information is the same as that in the second embodiment, and is not repeated here.

Preferably, after receiving the CQI information fed back by each STA, the CAP determines scheduling of the service of each STA in combination with upper layer service information including parameters such as service priority and QoS, and allocates corresponding physical layer transmission parameters to perform downlink data transmission, that is, transmit data to the corresponding STA.

To implement the method for implementing link adaptation, a fourth embodiment of the present invention further provides a network device, as shown in fig. 14, including:

Preferably, the channel quality information CQI feedback request can be encapsulated into a channel sounding frame at the MAC layer for transmission.

Preferably, in the sending unit 31, the CQI feedback request may be encapsulated into a channel sounding frame at the MAC layer and sent on a downlink transport channel at the physical layer.

To implement the method for implementing link adaptation, a fourth embodiment of the present invention further provides a terminal device, as shown in fig. 15, including:

a receiving unit 41, configured to receive a downlink probing channel and a CQI feedback resource indicator sent by a network device;

In order to implement the method for implementing link adaptation described above, a fourth embodiment of the present invention further provides a system for implementing link adaptation, including the network device and the terminal device provided in the fourth embodiment.

In the system, the network device, and the terminal device for implementing link adaptation provided in the fourth embodiment of the present invention, the working principle and the related operation flow are substantially the same as those in the foregoing implementation of the method for implementing downlink adaptation under the request-response based feedback mechanism, and details are not repeated here.

In summary, by using the request feedback mechanism provided in this embodiment, the CAP can configure and manage CQI feedback for multiple STAs at the same time, optimize resource configuration as much as possible, improve system efficiency, and implement that the CAP can arrange channel resources in a lump, so that the user can further multiplex on spatial resources, thereby improving spectrum utilization, adaptively scheduling spectrum resources, and improving spectrum utilization and system performance.

The embodiment of the present invention is described by taking a medium-short distance communication system as an example, but is not limited to be applied to the medium-short distance communication system, and other systems implemented by using the method of the present invention are within the protection scope.

It should be understood that the specific order or hierarchy of steps in the processes disclosed is an example of exemplary approaches. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the processes may be rearranged without departing from the scope of the present disclosure. The accompanying method claims present elements of the various steps in a sample order, and are not intended to be limited to the specific order or hierarchy presented.

In the foregoing detailed description, various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments of the subject matter require more features than are expressly recited in each claim. Rather, as the following claims reflect, invention lies in less than all features of a single disclosed embodiment. Thus, the following claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention.

What has been described above includes examples of one or more embodiments. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the aforementioned embodiments, but one of ordinary skill in the art may recognize that many further combinations and permutations of various embodiments are possible. Accordingly, the embodiments described herein are intended to embrace all such alterations, modifications and variations that fall within the scope of the appended claims. Furthermore, to the extent that the term "includes" is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term "comprising" as "comprising" is interpreted when employed as a transitional word in a claim. Furthermore, any use of the term "or" in the specification of the claims is intended to mean a "non-exclusive or".

Claims

1. A method for implementing link adaptation, comprising:

2. The method of claim 1, further comprising:

3. The method of claim 1, wherein the CQI feedback resource indication comprises an identification ID of a STA and an allocated resource indication; wherein,

4. The method of claim 1, wherein the CQI information is encapsulated at a MAC layer into a CQI feedback frame comprising a MAC header, a frame body, and an FCS; and feeding back the CQI information of each sub-channel or feeding back the CQI information of one or two sub-channels with better channels according to the CQI feedback resource indication.

5. The method of claim 1, wherein the CQI information is comprised of a Modulation Coding Scheme (MCS), a coding type, a signal to interference and noise ratio (SINR), and a subchannel mapping, wherein,

the coding type is used for identifying a coding mode recommended by the STA;

6. A network device, comprising:

a receiving unit, configured to receive CQI feedback information; and,

7. The network device of claim 6, wherein the sending unit is further configured to send a CQI feedback request; the CQI feedback request is indicated through a control channel of a physical frame or is encapsulated at the MAC layer to be transmitted as a sounding frame.

8. The network device of claim 6, wherein the CQI feedback resource indication comprises an identification ID of a STA and an allocated resource indication,

9. The network device of claim 6, wherein the CQI information is encapsulated at a MAC layer into a CQI feedback frame comprising a MAC header, a frame body, and a FCS; and feeding back the CQI information of each sub-channel or feeding back the CQI information of one or two sub-channels with better channels according to the CQI feedback resource indication.

10. The network device of claim 6, wherein the CQI information is comprised of a Modulation and Coding Scheme (MCS), a coding type, a signal to interference and noise ratio (SINR), and a subchannel mapping, wherein,

the coding type is used for identifying a coding mode recommended by the STA;