The encapsulated packet transmission method of wireless network
Technical field
The present invention relates to a kind of encapsulated packet transmission method, and be particularly related to a kind of encapsulated packet transmission method of wireless network.
Background technology
In recent years, Radio Network System (Wireless Network) is such as WLAN (WLAN), wireless MAN (WMAN) grows up in succession, the establishment of network also successively finish and provide service, wherein package voice and package video (PacketVoice/Video) are deemed to be one of most important application service project on the Radio Network System.Yet, provide instant messaging service (Real-timeCommunication Services) but to face a plurality of challenges at Radio Network System, for example wireless handheld device uses powered battery mostly, and power consumption (Power Consumption) problem need to overcome; The video of instantaneous communication system and voice data are regularly to produce and less package mostly in addition, will cause the impact of certain degree for the bandwidth usage of Radio Network System.
Review the design of Radio Network System mostly to transmit data packet (Data Packet) as main, do not carry out optimized improvement for the transmission of instant messaging package (Real-Time Packet).The characteristic of instant messaging package fails to utilize fully in the design of Radio Network System, for example instant messaging can tolerate that mostly the package of some degree loses, and the transmission that utilizes extra bandwidth to reach reliability will not be the most important consideration when transmitting voice data packet.Therefore, if can improve the power consumption that the network bandwidth uses capacity and improves hand-held device, will help to develop the instant messaging service of wireless network environment.
The operational process of standard 802.11 as shown in Figure 1, mobile communications device (MobileStation, MS) when transmitting package, if wireless medium has other mobile communications device to use, then mobile communications device can be waited for until wireless medium is unmanned uses, and then waits for a distributed collaborative interframe space (DCF Interframe Space, DIFS), begin competition window reciprocal (Contention Window, CW).After competition window inverse to 0, just begin to transmit, as require to transmit (RTS), determine to transmit the packages such as (CTS) control, or data (Data) and cut apart (Fragmentation) package (such as Frg#1 and Frg#2).After receiving terminal receives correct package, can send afterwards response (ACK) package through a short interframe space (ShortInterframe Space, SIFS) to transmitting terminal.
Please refer to Fig. 2, it is a kind of system construction drawing that uses instant messaging to serve wireless network.As shown in Figure 2, in wireless network side, one or more radio network devices 202,204 link to each other with access the Internet (Internet) 230 with the cable network end by wireless network memory access (Access Point) 210.Take up instant messaging package (uplink real-time frame) as example, package is at first delivered to the router (Router) 220 of same local area network (LAN) by wireless network memory access 210, then router two 20 is just delivered to the other end carries out the instant messaging service with it node (correspondent node) 240 with this package by Internet 2 30.And with descending instant messaging package (downlink real-time frame), package is at first delivered to router two 20 by Internet 2 30, and then router two 20 is delivered to radio network device 202 or 204 with this package by wireless network memory access 210.
And with present technology, in the time will using wireless network environment to transmit the instant messaging package, the simplest practice is forever to start network card, makes it forever can the sending and receiving package.Even but such design will be so that network card when not transmitting package, still needs power consumption.A kind of practice of improving power consumption is that wireless network is enabled in sleep state, and when having package to transmit, the wake on wireless network equipment is transmitted again, and this method is commonly referred to as the PS-Poll transfer mechanism.Please refer to Fig. 3, it consumes schematic diagram for package sequential chart and the corresponding energy that transmits instant package with PS-Poll mechanism in wireless network.As shown in Figure 3, radio network device (STA) just can carry out the transmission of up and descending instant messaging package after the line registration action of being correlated with.After up instant messaging package (UL Voice) was sent, therefore radio network device needed to continue the response package (ACK) of wait wireless network memory access (AP) owing to need to judge whether this heavy sending of this package.In addition, because radio network device is under the battery saving mode, fetch for the package that descending instant messaging package (DL Voice) needs to deposit in wireless network memory access buffering area by PS-Poll.Same, judge whether this heavy sending of this package for making the wireless network memory access, radio network device need be sent the response package to the wireless network memory access so that it confirms that this package correctly is received.Accordingly, reach reliability transmission for making the instant messaging package, will need to expend two short interframe spaces (SIFS) and two response packages more, therefore incite somebody to action so that the lifting on power consumption and the network bandwidth use capacity all is restricted.
If transmit the instant messaging package with the defined non-ordering automatic power save transmission mechanism of 802.11e (Unscheduled-Automatic Power Saving Delivery, U-APSD), then can further improve the power consumption of PS-Poll transfer mechanism.Please refer to Fig. 4, it consumes schematic diagram for package sequential chart and the corresponding energy that transmits instant package with U-APSD mechanism in wireless network.Compare with Fig. 3, mechanism shown in Figure 4 has been lacked the package of a PS-Poll, and remainder and Fig. 3 are similar, will not describe in detail at this.
Be the power saving effect of Da Gengjia, except above-mentioned power saving transmission mechanism, further develop many relevant media control technologys at present.Wherein, or synchronizing signal and the interval person who reduces mobile communications device and wireless network memory access (Access Point, AP) arranged; Or the problem that reduces hiding mobile communications device is arranged, reduce disturbance and collision reduce the probability person who heavily send package; Or the delivery status of the present wireless medium of observation is arranged, reduce the unnecessary receipts actor that send; Or have by data statistics or predict the time point person that next package send receipts; Or the transmission behavior of analyzing package long-time (Long Term) or short time (Short Term) is arranged, control to send and receive to avoid unnecessary power consumption person; Or there are the carrier sense multiple access of Standard modification and collision to avoid the transfer mechanism person of (CSMA/CA); Or have to be reduced in and transmit the control package person cut apart in the package; Or the increase protection mechanism is arranged, reduce the probability person that long package bumps in transport process; Or increase is arranged or revise feedback information (Feedback Message), help to adjust transmitting power person; Or there is minimizing heavily to send packet data unit or response package person.In addition, many other power conservation techniques are still arranged, as: reduce detection at park mode, reduce at the system's power consumption that receives short control package, the electricity-saving mechanism relevant with service quality (QoS), use time-division multiple access (Time Division Multiple Access, TDMA), use package to reserve the transmission etc. of the control information (Control Message) of multiple-access (Packet Reservation Multiple Access) and minimizing network.
Yet aforementioned all electricity-saving mechanisms have many meetings to be modified to 802.11 transfer mechanism, and incompatible with standard; Some is subject to the result who detects or assess and different power saving effects is arranged; Some then causes the power consumption of other parts in order to economize certain a part of power consumption; Some then causes other impact for reaching power saving effect, and usefulness (Throughput) reduces or broken string as transmitting.
In other words, every effort of carrying out for the power saving aspect at present has its defective place.Especially the electricity-saving mechanism of part can be because incompatible and cause inconvenience in the use with standard.Therefore, existing technology also can't effectively solve the problem that suffers from the instant messaging.
State with other objects, features and advantages and can become apparent on the present invention for allowing, preferred embodiment cited below particularly, and cooperate accompanying drawing, be described in detail below.
Summary of the invention
According to above-mentioned, purpose of the present invention is exactly that a kind of encapsulated packet transmission method of wireless network is being provided, this kind encapsulated packet transmission method transmits the package of instantaneity communication service by the multicast mechanism of 802.11 standard definitions, on compatibility, be and operating such, while can't be subject to assessment or the accuracy that detects and affect, can not reach power saving effect in the mode that increases the other parts power consumption yet, more can not cause other impact of mobile device, power conservation techniques by this motion except reach power saving effect, the bandwidth that also can increase whole network system is used capacity.
For reaching above-mentioned purpose, the present invention proposes a kind of encapsulated packet transmission method of wireless network, and it judges at first whether the package that will transmit is the instant messaging package.And when this package was the instant messaging package, namely signal strength signal intensity or the sending and receiving package Loss Rate according to wireless network determined whether this package is opened retransmission mechanism.
In one embodiment of the invention, further the common multicast medium access that uses of setting wireless access node and radio network device is controlled (MAC) address.And can be information exchange by this radio access node and this radio network device get in this multicast medium access control address, also can be to change the unicast network address of radio network device and get.
In one embodiment of the invention, when getting multicast medium access control address in the unicast network address of changing radio network device, it at first is the standard handovers program of carrying out unicast network address is converted to unicast media access control address, again the specific field in the network address in the specification standards is converted to afterwards multicast medium access control address and uses, so that the unicast media access
In another embodiment of the present invention, after judging that the package that will transmit is the instant messaging package, whether decision is to before this package unlatching retransmission mechanism, can integrate first a plurality of instant messaging packages is a descending chain package, and carries out package take this descending chain package as a unit of transfer and transmit.
In one embodiment of the invention, be in the descending chain package at a plurality of instant messaging packages of aforementioned integration, for each the instant messaging package that adds in the descending chain package so far, employed specified byte and corresponding medium access are controlled the length of packet data unit when at first being converted to multicast medium access control address according to unicast network address, produce a sub-header, be combined into a sub-package with corresponding medium access control package afterwards and with sub-header.After being combined into a plurality of sub-packages, be situated between by sub-header again and connect mode, each sub-package of chain combination.At last, before the result of this a little package gained of chain combination, add that a standard multicast medium access control header is to produce thus aforesaid descending chain package.
The present invention utilizes detection instant messaging package with non-instant messaging package and is separated, and when treating the instant messaging package, dynamically start and the retransmission mechanism of closing the instant messaging package, therefore can be in the situation that meets the existing network host-host protocol, effectively reduce detection instant messaging package and heavily send and retransmit the bandwidth of package, and improve thus network bandwidth use capacity and the hand-held device power consumption problem of Radio Network System.
State with other objects, features and advantages and can become apparent on the present invention for allowing, preferred embodiment cited below particularly, and cooperate accompanying drawing, be described in detail below.
Description of drawings
Fig. 1 is the operational process of standard 802.11.
Fig. 2 is a kind of system construction drawing that uses the wireless network of instant messaging service.
Fig. 3 consumes schematic diagram for package sequential chart and the corresponding energy that transmits instant package with PS-Poll mechanism in wireless network.
Fig. 4 consumes schematic diagram for package sequential chart and the corresponding energy that transmits instant package with U-APSD mechanism in wireless network.
Fig. 5 is according to the unicast mac address of IPv4 network specification standards and the schematic diagram of multicast MAC Address.
Fig. 6 is for being combined into a plurality of instant messaging packages that possess unicast ip address in the packet structure schematic diagram of a descending chain package.
Fig. 7 A is the operational flowchart that router carries out during from the node receive data according to one embodiment of the invention.
Fig. 7 B is the operational flowchart that router carries out during from wireless network memory access receive data according to one embodiment of the invention.
Fig. 8 A is the operational flowchart that radio network device carries out during from wireless network memory access receive data according to one embodiment of the invention.
Fig. 8 B is the operational flowchart that radio network device carries out data upload during to the wireless network memory access according to one embodiment of the invention.
The main element description of symbols
202,204: radio network device
210: the wireless network memory access
220: router
230: the internet
240: node
600,620,640: the package with unicast ip address
610,630,650: header
612,632,652: specified byte
660: descending chain package
670: the header of descending chain package
672a, 672b, 672c: sub-header
680a, 680b, 680c:MAC packet data unit
S700~S720: the implementation step of one embodiment of the invention
S730~S746: the implementation step of one embodiment of the invention
S800~S818: the implementation step of one embodiment of the invention
S830~S848: the implementation step of one embodiment of the invention
Embodiment
Below will describe with WLAN (WLAN), but content of the present invention is applicable to various Radio Network Systems, is not limited to use among WLAN.And embodiment will reach as example describes in detail take the dynamic correspondence of multicast/unicast address and apportion design and separate the concrete technological means that instant messaging package and non-instant messaging package heavily send mechanism, but also can dynamically start and close the voice data packet retransmission mechanism and reach effect of the present invention by other.
Please understand follow-up explanation referring again to network configuration shown in Figure 2 knowing.When the present invention being used in PS-Poll mechanism, radio network device 202 or 204 can be first to the operation that line registers of be correlated with of wireless network accessing apparatus 210 and router two 20, and with the other end carries out the instant messaging service with it node 240 to set up instant messaging online.Carrying out by this part action, wireless network memory access 210 just can be opened for the dynamic correspondence of the multicast/unicast address of radio network device 202 or 204 and the support of apportion design, and provides router two 20 to distinguish the call parameter of instant messaging package and non-instant messaging package.Then, radio network device 202 or 204 can be lost situation according to present communication quality quality or package, judges whether carry out the transmission of up and descending instant messaging package to close retransmission mechanism with multicast address at present.
In an IPv4 embodiment of the present invention, in carry out radio network device 202 or 204 with wireless network accessing apparatus 210 and router two 20 between relevant line registration operation the time, radio network device 202 or 204 at first need produce a legal multicast address (representing with multicast medium access control address MAC MA herein).The generation of this multicast address can by rear 23 positions with the unicast address (representing with unicast media access control address MAC STA herein) of this radio network device 202 or 204, produce in conjunction with the standard prefix (prefix) of multicast address MAC MA.Certainly, other technology that can reach the multicast address generation also can be used in this case.Then, radio network device 202 or 204 just carries out the line request to wireless network memory access 210.In this line request, it is parameter that radio network device 202 or 204 can carry multicast address MAC MA, and wireless network memory access 210 just can upgrade this parameter in present radio network device wire list after receiving this request.Perhaps, these multicast address MAC MA can be directly produced by the unicast address MAC STA of wireless network memory access 210 according to radio network device 202 or 204, and is like this then do not need extra information or data exchange operation.
And for descending instant messaging package that router two 10 can will deliver to radio network device 202 or 204 is transmitted with the multicast address of radio network device, radio network device 202 or 204 needs the ARP that uses address resolution communication protocol (ARP, Address Resolution Protocol) to upgrade router two 10 to tabulate.This moment, radio network device 202 or 204 network (IP) address will correspond to its multicast address MAC MA and unicast address MAC STA simultaneously.At last, distinguished instant messaging package and non-instant messaging package for making router two 10, the method of a kind of simple identification instant messaging package and non-instant messaging package can be finished by port numbers (Port Number), also be, router two 10 can by radio network device 202 or 204 and other end instant messaging node 240 when setting up the online invitation of instant messaging with Session Description Protocol (Session Description Protocol, SDP) whether information, recording the online used port numbers of this instant messaging is the usefulness of instant messaging package for next distinguishing.In addition, whether use specific address header, package whether to carry out etc. according to customizing messages exchanged form (as the aforementioned SDP) such as package, also can be used as and judge whether package is the foundation of instant messaging package.
After having carried out the preposition work of aforesaid package transmission, just can begin to carry out the actual transmissions of package.According to technology of the present invention, the package transmission of this moment can be divided into two kinds of instant messaging package and non-instant messaging packages easily.For non-instant messaging package, be not do special processing in the present embodiment.But this is not to mean these non-instant messaging packages just can not make change in any transmission, and this can know for the person of ordinary skill in the field, does not repeat them here.On the other hand, for the instant messaging package, the present invention will determine whether according to the transmission state of wireless network it is opened retransmission mechanism.For instance, radio network device 202 or 204 can be divided into several periods with time span t with its transport behavior on time shaft, and by the parameters such as sending and receiving package Loss Rate (Packet Lost Rate) that signal strength signal intensity (RSSI) or upper network layer provide, judge present network condition quality.In other words, in the present invention, can make radio network device 202 confirm a signal strength signal intensity every one section scheduled time t, and close the retransmission mechanism of instant messaging package during greater than a certain default value in signal strength signal intensity.Or, also can namely confirm sending and receiving package Loss Rate one time every one section scheduled time t, and when sending and receiving package Loss Rate is higher than a certain default value, open the retransmission mechanism of instant messaging package.
In one embodiment of the invention, whether control opens the function of the retransmission mechanism of instant messaging package, and whether be becomes the multicast package by the above-mentioned instant messaging package of control to decide.Because according to existing Internet Transmission specification, the multicast package will not have the mechanism that package retransmits, if therefore can transfer the instant messaging package to multicast from clean culture, just can reduce the whole time that the instant messaging package transmits.Change the mechanism different from other, in the package conversion that must unicast to multicast, the present invention be with network layer (IP layer) still for the package of unicast state when entering data link layer (Data Link Layer), change its medium access control (Medium Access Control, MAC) header of address is so that the MAC Address of above-mentioned package can be converted to the mode of multicast.
Please refer to Fig. 5, it is according to the unicast mac address of IPv4 network specification standards and the schematic diagram of multicast MAC Address.As shown in Figure 5, for present Internet Transmission specification, unicast mac address just is that from the difference of multicast MAC Address its address front end has different values.Therefore, as long as with the content of the specific fields of the unicast mac address in the specification standards (in the specification standards of IPv4, indication is front 25 positions of MAC Address herein, and in the specification standards of IPv6, the indication person then is front 16 positions of MAC Address herein) be converted to the content that the multicast medium access is controlled the specific fields of address, just can easily unicast mac address be converted to the multicast MAC Address.According to this point, after obtaining an instant messaging package with unicast networks (IP) address, can advanced be about to unicast network address is converted to the standard handovers program of unicast mac address (these standard handovers programs is different because of different network standards, but its conversion should be the person of ordinary skill in the field to be known, so do not repeat them here).
After being converted to unicast mac address, the standard content that next just must will meet according to the mode of Fig. 5 the specific fields of the unicast mac address in the network specification standards is converted to the standard content of the specific fields of multicast MAC Address, so that unicast mac address becomes the multicast MAC Address.At last, when decoding, really be mistaken as the instant messaging package of multicast for the instant messaging package that prevents clean culture, in the present embodiment, can use predefined multicast address group, also be that MAC Address belongs to address in this group then to be considered as this package be instantaneity communication package, if at this point in the group of location, then be not considered as general multicast package.
In addition, more can further the instant messaging packet intergration with same alike result be become a descending chain package together, and carry out package with this descending chain package as a delivery unit and transmit.Wherein, these attributes can be power consumption, service quality (QoS), fail safe, propagation delay or delay jitter etc.Please refer to Fig. 6, it is for being combined into a plurality of instant messaging packages 600,620 and 640 that possess unicast ip address in the packet structure schematic diagram of a descending chain package 660.In the present embodiment, utilize the aforementioned specified byte 612,632 and 652 of giving up when unicast ip address is converted to the multicast MAC Address, add the length of follow-up MAC packet data unit (680a, 680b and 680c), produce new sub-header (Sub-Header) 672a, 672b and a 672c, add MAC packet data unit 680a, 680b and 680c and be combined into one by one sub-package (Sub-Packet).Also namely, 672a and 680a are charge-coupled to be a sub-package, and 672b and 680b are charge-coupled to be a sub-package, and 672c and 680c are charge-coupled to be a sub-package.Then, a plurality of sub-packages use chain mode to be combined into a long package by the mode that sub-header is situated between and connects, and add the multicast MAC header 670 of a standard to produce descending chain package 660.
In said process, the content of sub-header can be done according to IP version change, and simultaneously the length of sub-package can change according to the length of MAC packet data unit in fact.And other data packet can according to conversion originally and transfer approach operation, not be affected yet.Utilize this technology just can possess same alike result with a plurality of, comprise power consumption, QoS, and the single MAC package of the chain one-tenth of package of fail safe etc. transmit, can reduce on the one hand the added burden (Overhead) when transmitting, also reduce the transmission competition between package and package simultaneously.This mechanism will possess package of the same type and use transfer approach of the same type to transmit, and such as propagation delay (Delay), delay jitter (Jitter) or other attribute, cooperate the algorithm operation.
And using under the situation of descending chain package, in network environment as shown in Figure 2, mobile communications device 202 or 204 and the operation of router two 20 can slightly make an amendment in order to operate accordingly support.Please refer to Fig. 7 A, it is router two 20, or other possesses the network equipment of the 3rd layer of disposal ability, the operational flowchart that carries out during from node 240 receive data according to one embodiment of the invention.When this device receives the TCP/IP package that is transmitted into by external network (step S700), distinguish at first whether this package belongs to instant messaging package (step S702, S704), if not the instant messaging package, then use general the processing and transfer approach transmission (step S706).If the instant messaging package, then this package of identification belongs to any service mechanism (step S708).Then judge whether that according to the service mechanism that whether belongs to same type needs produce sub-package (step S710).If need to produce sub-package, then the sub-header (step S712) under then producing by conversion program adds that its packet data unit produces a sub-package (step S714).Do not need to set up sub-package or built erect sub-package after, calculate to judge whether to arrive the delivery time (step S716) by algorithm with that.If do not reach the delivery time, then this sub-package is put in process (Schedule) or the formation (Queue), wait for the time (step S720) of transmitting; Otherwise, if reached the delivery time, then produce a new multicast MAC header that belongs to these service mechanism kinds, and the single package of the chain one-tenth of sub-package in process or the formation sent out (step S718).
Next please refer to Fig. 7 B, it is router two 20, or other possesses the network equipment of the 3rd layer of disposal ability, the operational flowchart that carries out during from wireless network memory access 210 receive data according to one embodiment of the invention.In the present embodiment, when receiving package from wireless network memory access 210, namely do identification for the header of this package and process (step S730).If be found to be the package of non-multicast after the identification, then the method for Application standard is processed (step S732); Otherwise, if be found to be the package of multicast after the identification, then process the header (step S734) of multicast package, and whether identification belongs to predefined instant messaging package (step S736).If find it is not predefined instant messaging package through the identification of step S736, then use the method for general multicast to process (step S738); Otherwise if predefined instant messaging package, then the sub-header (step S740) of decipher package is then processed sub-packet data unit (step S742), then sub-header is removed and package is passed to the upper strata to process (step S744).Check at last whether also have the sub-package of next group (step S746), if having then do identical processing (step S740~S746) is if nothing then finishes this program.
Next please refer to Fig. 8 A, the operational flowchart that it carries out during from wireless network memory access 210 receive data according to one embodiment of the invention for radio network device 202 or 204.In the present embodiment, when mobile communications device 202 or 204 receives the package that transmits into from external network by wireless network memory access 210, can determine whether first multicast package (step S800), if not then the method for establishing criteria is processed package (step S802).If the package of multicast then processes (step S804) for header.Judge then whether this package belongs to predefined instant messaging package (step S736), if not then the method for establishing criteria is processed (step S802); If then do subsequent treatment for this package.At first, check that whether to one's name sub-header to judge the sub-package of this batch (step S808, S810), if not then ignore the sub-package of this batch (step S812), then checks the sub-package of next group (S818); Otherwise, if the sub-package of this batch to one's name, then process (step S814) for sub-package, sub-header removed and solve pass to the upper strata behind the sub-packet data unit and process (step S816), then check the sub-package of next group (step S818), until whole multicast package is all complete by decipher.
Next please refer to Fig. 8 B, the operational flowchart that it carries out data upload during to wireless network memory access 210 according to one embodiment of the invention for radio network device 202 or 204.Wherein, when radio network device has data to send out (step S830), this TCP/IP package (step S832) of can classifying first.If not predefined instant messaging package is then processed and is transmitted according to the general data treatment principle (step S834, S836); And if predefined instant messaging package, then judge whether to belong to any specific service mechanism (step S834, S838), and then produce sub-header (step S840) corresponding to this service mechanism, add that then the packet data unit forms a MAC package (step S842).Calculate according to process or algorithm whether this sends out (step S844) afterwards, if this sends out, then transmit principle according to multicast this package is sent out (step S846); If not yet arrive the delivery time, then this sub-package is put into that process or formation are medium to be treated the transmission time (step S848).
Can know by above-mentioned various explanations and to learn that the present invention is whether to be that the package of multicast type is to determine to open or close the package retransmission mechanism by ACTIVE CONTROL instant messaging package.And whether control instant messaging package be wherein a kind of mode of multicast type is exactly to utilize the means of aforementioned change MAC Address to reach.If method provided by the present invention is used on the PS-Poll transfer mechanism, then owing to used multicast address to transmit in up and descending instant messaging package transmission, therefore can close the time of heavily sending mechanism and then reducing the wait-for-response package, by reducing two short interframe spaces and two response packages, radio network device just can improve for power consumption situation and network bandwidth utilization rate simultaneously.Identical, method provided by the present invention also can be applicable on other instant messaging electric-saving transmission method such as the U-APSD, this moment is owing to used multicast address to transmit in up and descending instant messaging package transmission, therefore can close the time of heavily sending mechanism and then reducing the wait-for-response package, by reducing two short interframe spaces and two response packages, therefore can improve for power consumption situation and network bandwidth utilization rate simultaneously equally.Show according to experimental result, on the network bandwidth, can improve about 40% utilization rate, and also can save at the same time about 40% power consumption.
Although the present invention discloses as above with preferred embodiment; so it is not to limit the present invention; any person of ordinary skill in the field; without departing from the spirit and scope of the invention; when can doing a little change and improvement, so the present invention's protection range is as the criterion when looking the claim person of defining.