Patent Application
20150036588
This application claims priority to and the benefit of Korean Patent Application No. 10-2013-0091109 filed in the Korean Intellectual Property Office on Jul. 31, 2013, the entire contents of which are incorporated herein by reference.
(a) Field of the Invention
The present invention relates to a method and apparatus that can use an existing transport network so as to extend a wireless sensor network, and that can multiplex and transmit a packet.
(b) Description of the Related Art
In general, most packets that are transported through an existing wireless network are short data of less than 127 bytes, that have directionality, and that are transported to a predetermined path. According to an increasing trend of using sensor nodes that generate data in a wireless sensor network, a quantity of data that are transmitted/received through a network is rapidly increasing. Therefore, in order to effectively enlarge a network according to extension of a sensor network service area, a necessity to effectively use an existing transport network is increasing.
However, because an existing transport network is optimized for an existing service, it is inefficient to use the existing transport network as a transport network for a wireless sensor network having a short length and a small data amount. For example, in a wireless sensor network, a small amount of data occurs in a large number of nodes, and the amount of data is not large, but when a transmitting/receiving terminal processes a large number of packets, the load is large. However, in an existing service, a relatively large amount of data occurs in a small number of nodes compared with a wireless sensor network, and thus a wireless sensor network represents a different characteristic from a service of an existing network in which the number of packets is relatively small and in which a size of a packet is large.
Because performance of a packet network service is more sensitive to the number of packets that should be processed than an absolute amount of data, such a phenomenon may become a serious problem. Therefore, because a sudden increase of the number of packets in a wireless sensor network adds a burden to various functions that an existing transport network does not consider, it is difficult to use the wireless sensor network as an effective transport network.
The present invention has been made in an effort to provide a method and apparatus for multiplexing a wireless sensor network packet having advantages of efficiently transporting wireless sensor network data using an existing transport network.
An exemplary embodiment of the present invention provides a method of multiplexing a packet in a wireless sensor network, the method including: determining whether to multiplex a packet that is generated in a node constituting the wireless sensor network; generating, if the packet is to be multiplexed, a frame of a first length by multiplexing at least one packet; and transmitting the frame of the first length, wherein in the frame of the first length, a data portion including a data unit and a header unit having a second length smaller than the first length includes at least one multiplexed payload.
The determining of whether to multiplex may include determining that multiplexing of a packet is to be performed when the packet is transmitted through a transport network that is connected to the wireless sensor network, and determining that multiplexing of a packet is to be performed when the packet is directly transmitted between nodes constituting the wireless sensor network instead of being transmitted through the transport network.
Packet transmission through the transport network may include transmission of a packet between nodes through a transport network instead of being transmitted through a gateway and transmission of a packet between nodes through a gateway.
The generating of a frame of a first length may include generating a frame of the first length by multiplexing packets having the same destination address. The frame of the first length may be a management MAC packet data unit (L-MPDU), and the data unit of the second length may be an S-MPDU. The frame of the first length may further include a first frame header portion including information that is related to the payload, a second header portion including length information of the frame, and a frame check sequence (FCS) for checking an error. The frame may be formed in order of the second header portion, the first header portion, the payload, and the FCS, and the first length may represent a length from the first header portion to the FCS.
Another embodiment of the present invention provides a packet multiplexing apparatus in a wireless sensor network, the packet multiplexing apparatus including: a packet generator that generates a packet corresponding to data to be transmitted in a random node constituting a wireless sensor network; a multiplexing determination unit that determines whether a packet is to be transmitted through a transport network and that determines whether to multiplex; a packet multiplexer that multiplexes at least one packet that is determined to be multiplexed; and a packet transmitter that generates and transmits a frame including the multiplexed packet, wherein the frame has a first length and includes at least one data portion including a data unit having a second length smaller than the first length and a header unit that is related to the data unit.
The packet multiplexer may multiplex packets having the same destination address. The multiplexing determination unit may determine whether a corresponding packet is a packet to be transmitted through transport network transmission based on a destination address of the packet.
In the following detailed description, only certain exemplary embodiments of the present invention have been shown and described, simply by way of illustration. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.
Accordingly, the drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements throughout the specification.
In addition, in the entire specification and claims, unless explicitly described to the contrary, the word “comprise” and variations such as “comprises” or “comprising” will be understood to imply the inclusion of stated elements but not the exclusion of any other elements.
Hereinafter, a method and apparatus for multiplexing a packet in a wireless sensor network according to an exemplary embodiment of the present invention will be described.
A frame according to an exemplary embodiment of the present invention includes a first header portion F1 and a payload portion F2 including at least one data portion, and further includes a second header portion F3 and a frame check sequence (FCS) portion F4 for checking an error.
Such a packet frame has a first length, and the first header portion F1 includes information that is related to the payload portion F2 and is referred to as a MAC header (MHR).
The payload portion F2 includes a plurality of data portions, and is referred to as a MAC payload. Each data portion (for convenience of description, F2 is a representative reference numeral) constituting the payload portion is referred to as a management MAC packet data unit (mMPDU). Each data portion includes a header unit F21 and a data unit F22 including length information, as shown in
The second header portion F3 includes information about a frame length. The second header portion F3 is referred to as a PHY header (PFR). The first length is a length from the first header portion F1 to the FCS F4, except for the second header portion F3 that is positioned at the forefront of a frame.
In an exemplary embodiment of the present invention, as shown in
A maximum length of an MPDU was generally limited to about 127 bytes, but recently, may be extended to 2047 bytes. A maximum MDPU of the first length (e.g., about 2047 bytes) is referred to as an L-MPDU, and a maximum MPDU of the second length (e.g., about 127 bytes) is referred to as an S-MPDU.
In an exemplary embodiment of the present invention, an S-MPDU of the first length is multiplexed by an L-MPDU of the second length, and a multiplexed target is a header unit and a data unit. As shown in
Table 1 represents a MAC frame type in which a method of multiplexing a packet according to an exemplary embodiment of the present invention is applied.
A kind of a frame according to an exemplary embodiment of the present invention may be classified like Table 1 according to a frame type value. Specifically, the kind of a frame includes a beacon frame (b2, b1, b0: 000) for transmitting/receiving a beacon, a data frame (b2, b1, b0: 001) for transmitting/receiving data, an acknowledgment (ACK) frame (b2, b1, b0: 010) for determining whether data reception has succeeded, and a frame (b2, b1, b0: 011) for a MAC command, and includes an L-MPDU of a first length, i.e., an aggregated MPDU frame (b2, b1, b0: 100) that is formed by multiplexing an S-MPDU of at least one second length according to an exemplary embodiment of the present invention.
The aggregated MPDU frame (b2, b1, b0: 100) according to an exemplary embodiment of the present invention includes a first header portion F1, which is a MAC header, and a payload portion F2 including at least one data portion, as shown in
Hereinafter, a method of multiplexing a packet using such a frame will be described.
Upon multiplexing a packet, when final destination addresses of each packet are the same, the packet may be multiplexed, and when next hops of each packet are the same, the packet may be multiplexed. In a case of the latter, a switching function of disassembling and reassembling in every hop is necessary, and thus as complexity increases, in an exemplary embodiment of the present invention, when final destination addresses are the same, an example of performing multiplexing is described. However, the present invention is not limited thereto. A standby time for multiplexing is determined according to an allowance delay time request condition of a service.
As shown in
A case “b” of
The case “a” of
A packet having occurred in a node constituting a sensor network is data having a short length, and in an exemplary embodiment of the present invention, by multiplexing data instead of repeatedly transmitting data several times, data is processed and transmitted as one packet.
When a random node constituting a wireless sensor network attempts to transmit packet data to another node, a packet multiplexing apparatus determines whether a packet is transmitted through a transport network (S100 and S110). In a network environment of
When packet multiplexing is performed, by multiplexing packets to be transmitted, a packet frame is generated. That is, by multiplexing at least one of data portions including a data unit, which is a packet having a second length, and a header unit that is related thereto, the payload portion F2 is generated (S140). Here, destination addresses of multiplexed data portions are the same.
By multiplexing at least one of data portions having a data unit of the second length, the payload portion F2 is formed, and by coupling a first header portion F1 including information that is related thereto, a frame of the first length to be transmitted is generated. The generated frame of the first length is transmitted (S150).
A data packet of a short length is repeatedly transmitted through such a process, but by processing and transmitting with a frame of a longer length by multiplexing such data packets, in a wireless sensor network, a processing load according to a repeated transmitting/receiving processing of a packet of a small size can be reduced.
As shown in
The packet generator 110 generates a packet corresponding to data to be transmitted in a random node constituting a wireless sensor network.
The multiplexing determination unit 120 determines whether a generated packet is transmitted through a transport network, and determines whether to multiplex. If a packet is directly transmitted between nodes, the multiplexing determination unit 120 determines that packet multiplexing is not to be performed, and transports the corresponding packet to the packet transmitter 140. If a packet is transmitted through the transport network, the multiplexing determination unit 120 determines that packet multiplexing is to be performed, and transports the corresponding packet to the packet multiplexer 130.
The packet multiplexer 130 multiplexes packets to be transmitted. The packet multiplexer 130 generates a payload portion by multiplexing at least one of data portions including a data unit, which is a packet having a second length, and a header unit that is related thereto, and provides the payload portion to the packet transmitter 140. Destination addresses of the multiplexed data portions may be the same.
The packet transmitter 140 generates a frame by coupling a header portion including related information to a packet to be transmitted, and transmits the generated frame. Particularly, the packet transmitter 140 multiplexes at least one of data portions having a data unit of a second length that is transported from the packet multiplexer 130, and generates and transmits a frame of the first length by coupling the first header portion including related information to a generated payload portion.
According to an exemplary embodiment of the present invention, data of a wireless sensor network can be effectively transported through an existing transport network. Therefore, a service can be extended using an existing transport network. Further, when forming a network with only a wireless sensor network, wireless sensor network backhaul can be formed, and when a transport network connection for extending a service is necessary, an effective network connection is available.
An exemplary embodiment of the present invention may not only be embodied through the above-described apparatus and/or method, but may also be embodied through a program that executes a function corresponding to a configuration of the exemplary embodiment of the present invention or through a recording medium on which the program is recorded, and can be easily embodied by a person of ordinary skill in the art from the description of the foregoing exemplary embodiment.
While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2013-0091109 | Jul 2013 | KR | national |
