CN102469561B

CN102469561B - Method for realizing 802.11n low power consumption

Info

Publication number: CN102469561B
Application number: CN201010546867.9A
Authority: CN
Inventors: 周朝显; 李霞; 张树华
Original assignee: Beijing CEC Huada Electronic Design Co Ltd
Current assignee: Beijing CEC Huada Electronic Design Co Ltd
Priority date: 2010-11-16
Filing date: 2010-11-16
Publication date: 2015-01-07
Anticipated expiration: 2030-11-16
Also published as: CN102469561A

Abstract

The invention provides a method for realizing 802.11n low power consumption. The method comprises the following steps that when a virtual carrier timer is required to upgrade, an energy-saving mechanism can only be applied to aggregation Mac protocol data unit (A-MPDU) receiving, after a first correct sub-frame detected by a frame check sequence (FCS) is received, if the sub-frame is not the frame required to receive by equipment, a Base Band, an analog-to-digital converter (ADC) and a radio frequency (RF) transceiver can be placed in an energy-saving state in the respectively subsequent continuous time of the A-MAPDU. In this way, in a long time period, the power consumption of the base band, ADC and RF transceiver can be reduced. Secondly, when the virtual carrier channel protection is not used, as for the common frame of the non A-MPDU, after a frame header address domain is received, if the frame is found not the frame required to be received by the equipment, the three modules can be placed in the energy-saving state in the continuous time of the subsequent part of the frame. In a word, as the three modules consume most of the power consumption of an acquisition channel, in the specified time period, the method provided by the invention can be used for reducing the power consumption of the three modules, and the power consumption of the equipment can be saved greatly.

Description

A kind of 802.11n method for realizing low power consumption

Technical field

The invention belongs to WLAN (wireless local area network) field, as a kind of 802.11n method for realizing low power consumption, be specially adapted to the wireless device chip design of 802.11n, be also applicable to the chip design that other have the wireless communication field of similar frame structure definition.The method for realizing low power consumption that the present invention proposes, can very large reduction WLAN devices power consumption.

Background technology

The chief component of the receiving path of wireless device is: 1, RF Transceiver; 2, ADC; 3, Base Band; 4, MAC.When receiving path carries out work, the power consumption of former three occupies the overwhelming majority of receiving path power consumption.And air frame, comprise the A-MPDU aggregate frame that 802.11n agreement specifies, mail to different target wireless device.Meeting under the prerequisite that 802.11 serial protocols specifys herein, proposing a kind of match condition according to air frame target device and local device, close the partial circuit of local reception path in good time, thus save reception power consumption.

The frame structure of 802.11 Frames is as Figure of description 1, Frame Header comprises recipient's address field, recipient is mated with local address according to this recipient's address field, receives and is uploaded to the Frame on upper strata, otherwise do not need to be uploaded to upper strata if coupling is needs.If secondly address is not mated, whether correctly then detect according to FCS, carry out renewal virtual carrier timer initial value being carried out to Different Strategies.

The structure of the A-MPDU of 802.11n definition is as Figure of description 2.Each A-MPDU can carry multiple Frame, and the frame structure of each Frame is as Figure of description 1.Recipient's address field of all Frames is identical, and in the same circumstances, to the renewal of virtual carrier timer too, is also say, if address is not mated, has a Frame FCS to detect correct, then upgrade virtual carrier timer according to the situation of this frame.

The wireless device of 802.11n, generally, air-data frame mostly is and is aggregated in that A-MPDU inside carries out transmitting, and secondly 802.11n also allows block response limiting frame (Immediate Compressed Block Ack) to be aggregated in A-MPDU, transmits as the first frame.Block response limiting frame is the same with subsequent data frame meets above-mentioned mechanism for this.

802.11 agreements have double for the protection that channel uses, actual physical carrier protection, and virtual carrier protection, in detail can with reference to 802.11 serial protocols.

Summary of the invention

According to 802.11 agreements, the normal frames of non-A-MPDU receives, and needs to receive completely.Even if be not the frame that this equipment needs to carry out being uploaded to upper strata, also will carry out FCS detection, according to FCS testing result, selection strategy carries out virtual carrier timer initial value and upgrades.Upgrade so carry out virtual carrier timer initial value to abide by the agreement, harvesting frame head (frame header) if find that address is not mated afterwards, in order to save power consumption within the time period that frame (frame body) receives, the operating state of RF Transceiver, ADC, Base Band tri-parts in receiving path can not be closed.

For A-MPDU frame, because correct subframe can be detected according to first, its inside FCS carry out matching addresses and the renewal of virtual carrier timer, after discovery address is not mated and has been carried out the renewal of virtual carrier timer, in the duration section of A-MPDU subsequent content, the operating state that just RF Transceiver, ADC, Base Band tri-can be formed department is closed.

For block response limiting frame as first sub-frame aggregation in A-MPDU, or the situation of other frame aggregations in A-MPDU of other non-data frame type, can adopt said method to carry out energy-conservation all completely.Figure of description 3, illustrates above-mentioned accepting state transition process.

But under considering application-specific scene, the virtual carrier that must adopt can violating 802.11 carries out the regulation of channel guard, because adopt separately actual physical carrier wave to carry out channel guard, also can communicate completely.Thus for the reception of normal frames, receiving after frame head finds that address do not mate, within the time that the contents such as follow-up frame and FCS continue, MAC just can close operating state by control RF Transceiver, ADC, Base Band automatically, can save the power consumption of three parts like this in this time period, and the power consumption of these three parts occupies the overwhelming majority of the power consumption of full equipment in current slot.For this control situation, the present invention is referred to as " the special closedown of normal frames receives energy-conservation realization "." normal frames special closedown receive energy-conservation realization " comprises address when not mating, and closes the operation of three parts after receiving path, and time opening operation.

Under this special applications scene not using virtual carrier channel guard; after A-MPDU receives and also must detect correct subframe receiving first FCS; upgrade if address is not mated and carried out virtual carrier timer; in the duration section of A-MPDU subsequent content, the operating state of RF Transceiver, ADC, Base Band tri-parts can be closed.So receive for A-MPDU, no matter whether enable virtual carrier channel guard, the implementation method of this low-power consumption is all the same.For the control situation that this A-MPDU receives, the present invention is referred to as " A-MPDU closes and receives energy-conservation realization "." A-MPDU close receive energy-conservation realization " comprises address and not to mate and after having upgraded virtual carrier timer, closes the operation of three parts after receiving path, and time opening operation.

Under this special applications scene, after why A-MPDU reception can not find that at the frame head receiving first subframe address not mated, just reception is closed from the body section of this frame, because the frame head of this frame of possibility may be wrong (FCS of this frame detects inevitable also incorrect), but the FCS of subsequent subframe may be correct, and this A-MPDU is also this device address coupling.

Under this special applications scene, for block response limiting frame as first sub-frame aggregation in A-MPDU, or the situation of other frame aggregations in A-MPDU of other non-data frame type, can adopt said method to carry out energy-conservation all completely.Figure of description 4, illustrates above-mentioned accepting state transition process.

Accompanying drawing explanation

Fig. 1 normal frames structure

Fig. 2 A-MPDU structure

Energy-conservation accepting state figure when the protection of Fig. 3 virtual carrier is enable

Energy-conservation accepting state figure when the protection of Fig. 4 virtual carrier does not have enable

Embodiment

Below in conjunction with accompanying drawing, specifically introduce embodiments of the present invention:

MAC is designed with virtual carrier protection enable bit, enable when being effective, enable virtual carrier channel guard, that is to say that aforesaid method for realizing low power consumption must observe 802.11 agreement regulations, adopt above-mentioned method for realizing low power consumption, the general frame of non-A-MPDU must receive, and A-MPDU receives and can adopt " A-MPDU closes and receives energy-conservation realization "; Enable invalid time; do not use virtual carrier channel guard; adopt above-mentioned method for realizing low power consumption, the normal frames of non-A-MPDU receives and can adopt " the special closedown of normal frames receives energy-conservation realization ", and A-MPDU receives and can adopt " A-MPDU closes and receives energy-conservation realization ".

No matter be " the special closedown of normal frames receives energy-conservation realization " or " A-MPDU closes and receives energy-conservation realization ", all first, to calculate from closing initial point, namely complete and judge that will carry out above-mentioned two kinds of time points of closing the energy-conservation realization of reception starts, aloft terminate to this normal frames or A-MPDU, length during this period of time.Calculate need use parameter be this frame from closing the byte length of pilot to frame end part, and this frame transmission physical layer rate.For length during this period of time, a time period threshold parameter is set, if be less than this time period threshold parameter during this period of time, no longer will carry out closedown and receive operation, and because energy-saving efficiency may be too low like this, even have negative effectiveness.

Base Band is in the receiving course of a frame, and must be able to be reset receiver, and whole BaseBand circuit can be made to enter power save mode.Here power save mode can be power off state, or other the various energy-saving design states such as clock closed condition that power on.Concrete power save mode design, determines according to real needs.If Base Band has change-over time returning to operating state from power save mode, then require to convert and must occur in before this frame disappears aloft.

ADC and RF transceiver closedown receive energy-conservation during this period of time in, different power save modes can be entered, Standby, Power Down or local power down.Generally do not advise carrying out overall power down to RF transceiver module, unless the operation such as configurating channel parameter fast can be carried out.Because ADC and RF transceiver is transformed into normal operating conditions from power save mode need change-over time, must occur in before this frame disappears aloft so require to convert.

Claims

1. a 802.11n method for realizing low power consumption, is characterized in that: MAC is designed with virtual carrier enable bit, when enable bit is enable, has both used physical carrier protected mode, also uses virtual carrier channel guard mode; When enable bit is not enable, only use physical carrier protected mode;

Wherein when virtual carrier enable bit is not enable, normal frames is when receiving frame head address field, if address is not mated, within the further part duration of this normal frames, control Base Band, ADC, RF transceiver enters energy saver mode;

A-MPDU frame receives and has nothing to do with virtual carrier enable bit, receiving after first FCS detect correct A-MPDU subframe, the address field using this A-MPDU subframe to carry carries out matching addresses, if address is not mated, in this A-MPDU subframe subsequent duration, control Base Band, ADC, RF transceiver enters energy saver mode, and time opening operation; When virtual carrier enable bit is not enable, during the channel disappearance aloft of the unmatched normal frames in address, Base Band, ADC, RF transceiver returns to normal operating conditions, and wherein Base Band was reset before entering normal operating conditions; When virtual carrier is enable, all normal frames all normally receive; During the channel disappearance aloft of the unmatched A-MPDU frame in address, Base Band, ADC, RF transceiver returns to normal operating conditions, and wherein Base Band was reset before entering normal operating conditions.