Patent Application
20190059017
The present invention relates to controlling communications resources by a node of a communications network, and in particular to flood control by a node of a multi-hop network.
Reduced quality of service is resulted when a network node is carrying more data than it can handle. Typical effects include queueing delay, packet loss or the blocking of new connections. Network protocols that use aggressive retransmissions to compensate for packet loss due to congestion can increase congestion, even after the initial load has been reduced to a level that would not normally have induced network congestion. Networks use congestion control and congestion avoidance techniques to try to avoid congestive collapse, for example exponential backoff in protocols such as the IEEE 802.11 CSMA/CA and the Ethernet and window reduction in TCP. Another method is to implement priority schemes, transmitting some packets with higher priority than others. A third avoidance method is the explicit allocation of network resources to specific flows.
Operation of network node devices is typically designed to cope with maximum/peak load. When there is no data to transmit or receive during an idle period of an active data connection, overall power consumption is naturally reduced, but the device typically still operates with the same processing intensity and the provided communications resource is just not used. There is need to provide further improvements in communications resource control particularly for communications devices for which it is essential to achieve as low power consumption as possible, such as standalone machine-to-machine M2M or Internet of Things IoT devices without external power supply.
The invention is defined by the features of the independent claims. Some specific embodiments are defined in the dependent claims.
According to a first aspect of the present invention, there is provided a method for a transmitting node of a communications network, comprising: transmitting packets via a transmission buffer by a first interface duty cycle, detecting a flood control condition of the transmission buffer, in response to detecting the flood control condition including a flood control indication in one or more packets, said one or more packets comprising a payload field, and transmitting the one or more packets by a second interface duty cycle.
According to a second aspect of the present invention, there is provided a method for controlling communications resources by a receiving node of a communications network, comprising: receiving a packet comprising a payload field by a first interface duty cycle, detecting a flood control indication in the received packet, in response to detecting the flood control indication, receiving one or more packets by a second interface duty cycle, and in response to detecting lack of flood control indication during reception of a packet by a second interface duty cycle, adapting interface duty cycle for packet reception.
According to a third aspect of the present invention, an apparatus comprising at least one processing core, at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processing core, cause the apparatus at least to perform a method according to the first aspect and/or the second aspect.
According to a fourth aspect of the present invention, there is provided a computer program configured to cause a method in accordance with at least one aspect to be performed.
According to a fifth aspect of the present invention, there is provided a non-transistory computer readable medium having stored thereon a set of computer readable instructions that, when executed by at least one processor, cause a network node to at least perform a method according to the first aspect and/or the second aspect.
Dynamic resource adaptation is now provided for transmitting and receiving devices, facilitating very low power consumption during idle or low-activity periods and instant increase of resources during flooding transmission conditions. Packets are first transferred by a first interface duty cycle. Upon detecting a flood control condition of a transmission buffer, a second interface duty cycle is entered and a flood control indication is included in one or more packets.
A flood or flooding herein refers generally to a situation where a large number of packets is to be or being transferred, causing a high load on the transmitter or receiver. The instant increase of packets to be transferred may have already caused or will likely cause the transmission or reception buffer to become full or overflow. For example, such situation may be caused by a multi-hop flooding transmission, without restricting to any particular transfer method. Thus, a specific resource increase procedure involving the changed interface duty cycle may be initiated to instantly meet the flood condition. The flood control condition refers to a predefined trigger causing the resource increase procedure and is detected by the network node on the basis of one or more threshold values. The flood control condition may be detected on the basis of fast increase of packets in a transmission buffer or a predetermined occupancy level of the transmission buffer being reached or exceeded.
The interface duty cycle herein refers to an operation period of a communications interface, comprising a transmission or reception event or activity and an idle period for power-saving, the proportion of which may differ. For example, during a normal or low-activity operation mode 100 millisecond duty cycle comprising one active transmission or reception event of around one ms and an idle period of 99 ms is applied. During a flooding condition the duty cycle may be substantially reduced, for example to 1 ms. The interface duty cycle may be alternatively defined as percentage or ratio of active transmission or reception event time of the total operation period (e.g. 20% duty cycle may refer to using 20% the operation period for transmission.
A flood control operation or mode triggered by the detection of the flood control condition may be initiated also on the basis of another trigger than the state of the transmission buffer. In some embodiments the packet to be transmitted may comprise, or an upper protocol layer may otherwise indicate, a high rate indication for increasing the data transmission capacity. For example, such high rate indication may be provided by an ON/OFF high rate bit in the packet format. Thus, the method may involve checking if a packet to be transmitted comprises or is otherwise associated with a high rate indication, e.g. by checking if the high rate bit is set ON. In response to the packet comprising the high rate indication, the packet may be transmitted with the flood control indication with the second interface duty cycle.
The high bit rate indication, in an embodiment illustrated in
However, it is to be appreciated that the method of
Phase 104 comprises checking the state of the transmission buffer, for detecting the flood control condition and triggering the flood control on the basis of the state of the buffer. The flood control condition may be detected in response to the amount of packets in the transmission buffer reaching a flood control condition threshold value, which may also be referred to as a flood control on threshold.
Phase 105 comprises setting the interface duty cycle to the second value applied for transmission of packet during the flood control condition. For example, minimum duty cycle of the available duty cycle values may be applied during the flood condition. However, it will be appreciated that the cited normal and minimum interface work cycles represent non-limiting examples and various other values within available work cycle values may be selected in steps 102 and 105. In some embodiments, the value in step 102 and/or 105 may be selected on the basis of further historical data processing or big data analysis. For example, time/date may affect the value selection based on historical resource usage information such that the work cycle value is during Mondays 9-12 am set smaller than 1-5 am. This further facilitates power saving at network nodes.
Phase 106 comprises including the flood control indication in the packet to be transmitted. The indication may be included in a packet next to be transmitted amongst the packets in the transmission buffer. In some embodiments the flood control condition and the lack of flood control condition are indicated by a state of a packet flood control bit. Phase 107 comprises transmitting the packet.
The transmission buffer is monitored during the flood control condition for determining if the flood control needs to be continued. In response to detecting termination of the flood control condition on the basis of the state of the transmission buffer, at least one packet is transmitted by the first interface duty cycle and without the flood control indication. The termination of the flood control condition may be detected based on the amount of packets in the transmission buffer falling under a flood control condition termination value.
Flood control, and data cycle and flood control indication, may thus be set for each packet in the transmission buffer. If the state of the buffer does not cause flood control condition, the high rate bit indication in a packet may still cause setting the flood control indication to the packet and transmitting the packet by the second interface duty cycle. After transmission of such packet, need for flood control indication and transmission by the second interface dutycycle may be determined separately for a subsequent packet in the transmission buffer.
With reference to the example of
In some embodiments the termination of the flood control condition may be detected or based on removal of the other trigger (than the state of the transmission buffer). The removal of such flood condition may be detected on the basis of a subsequent packet not including the high rate indication, for example if the VIP bit is OFF.
Phase 203 comprises receiving a packet by the first interface duty cycle. Phase 204 comprises checking for a flood control indication in the received packet, in some embodiments based on the state of the flood control bit in the received packet. In response to detecting the flood control indication in the received packet (flood control ON), the interface duty cycle is set, in step 205, to a second value facilitating increase in reception activity as signaled by the transmitter, in some embodiments to the minimum value.
Step 206 comprises receiving at least one packet (after the packet that caused entering the step 205) by the second interface duty cycle. Step 207 comprises checking if the received packet comprises the flood control indication. In some embodiments this is detected by checking the state of the flood control bit: ON or 1 referring to flood control indication and OFF or 0 to lack of flood control indication. In response to detecting the flood control indication, reception 206 for next packet is continued with the second interface duty cycle. In response to detecting lack of flood control indication, interface duty cycle for packet reception is adapted. In some embodiments the interface duty cycle is changed back 202 to the first interface duty cycle value, such as the normal interface duty cycle.
It will be appreciated that there may be some other value (than the first interface duty cycle value) applied after termination of the flood control condition and/or detection of lack of flood control indication, e.g. to enable gradual recovery from the flood control condition and duty cycle change after the termination of the flood control condition. Multiple receiving nodes for a packet comprising a flood control indication, and the nodes may apply the above illustrated features for flood control.
The domain address 302, source node identifier 303, target node identifier 304 and last node identifier 305 may indicate identifiers of the nodes. The identifiers may be unique in the network and used for addressing nodes within the network. The domain address may serve for identifying a domain of the network, whereby the identifiers may be unique within the domain. Formats of the identifiers and the domain address may be human-readable but also machine-readable data formats, for example Internet Protocol addresses or Medium Access Control (MAC) addresses are feasible. Identifiers of human-readable formats may be naturally read by humans, for example text in a selected character set for example ASCII character set. For example, the text may represent people names. The identifiers may be defined by user according to a desired logic. It should be appreciated that only a specific user may be authorized to manage node identifiers. The user authorized to manage node identifiers may be an administrator of the node and/or administrator of the network. The checksum 312 may serve for detecting errors in the packet.
The service source identifier 308 may serve for identifying a source application (App) and a service target identifier 309 may serve for identifying a target application. The payload 311 may serve for carrying data from a source node to a target node.
In some embodiments the network nodes are multi-hop and/or mesh network nodes and the packet comprises fields 305 and 307. The hop limiter 307 may serve for indicating a maximum time to live (TTL) of the packet. The TTL may be indicated by a number of hops. A connection between nodes of the mesh network may determine a single hop, whereby a transmission of the frame over a connection between nodes in the mesh network may cause an update of the hop limiter. Initially the hop limiter may be set to a maximum number of hops, whereby a hop may reduce the value of the hop limiter. The network address 301 may serve for indicating different mesh networks from each other. Packets cannot pass through different networks than the network address indicates.
The packet 300 may be processed by more than one protocols. The protocols may comprise a link layer protocol, a network layer protocol, a service layer protocol for example. Accordingly, at least some of the fields may be adapted to be processed by more than one protocol. A protocol stack may comprise protocols on a plurality of layers of the protocol stack for processing the packet.
The packet encapsulates data in the payload 311 to be transmitted on a physical layer. Preferably the packet is not limited to a digital data transmission unit of a single protocol or a protocols layer. Indeed the packet may serve for a digital data transmission unit of a plurality of protocols that are on different layers. Accordingly, the fields of the packet may be utilized by more than one protocol on different protocol layers. In one example, the source node identifier may be utilized on both link layer and a network layer.
At least some of the presently disclosed embodiments may be applied in a mesh network, such as a mesh network illustrated in patent application no. FI20175492. In the mesh network, a node that forwards a packet may change a last node identifier of the packet. It should be appreciated that payload of the packet may be unchanged in the forwarding. One or more nodes, even all nodes, other than the source node may update routing information to a route ring buffer, for example as described in
In an example procedure according to at least some embodiments, packets may be processed at the nodes by a protocol stack comprising the following layers in a top down order: application, service, network, link and physical. The packets may have the format described with
An electronic device comprising electronic circuitries may be an apparatus for realizing at least some embodiments of the present invention and capable of carrying out at least some of the features illustrated above. The apparatus may be or may be comprised in a computer, a laptop, a tablet computer, a cellular phone, a machine to machine (M2M) device (e.g. a sensor device), a wearable device, or any other apparatus provided with radio communication capability. In another embodiment, the apparatus carrying out the above-described functionalities is comprised in such a device, e.g. the apparatus may comprise a circuitry, such as a chip, a chipset, a microcontroller, or a combination of such circuitries in any one of the above-described devices.
The apparatus 500 may comprise a processor 501 and a memory 502, 503, and one or more communication interfaces 504. The processor may comprise one or more processing cores. The processor may comprise at least one application-specific integrated circuit, ASIC. The processor may comprise at least one field-programmable gate array, FPGA. The processor may be means for performing method steps in the device.
The memory may comprise random-access memory and/or permanent memory. The memory may comprise at least one RAM chip. The memory may comprise solid-state, magnetic, optical and/or holographic memory, for example. The memory may be at least in part accessible to the processor 501. The memory may be at least in part comprised in the processor 501. The memory may store a computer program comprising computer instructions that the processor is configured to execute, to cause one or more functionalities described in the embodiments. The processor and the memory may be operatively connected to the processor for communications of data for execution of the computer program by the processor. The connection between the processor and the memory may be a data bus for example. When computer instructions configured to cause the processor to perform certain actions are stored in the memory, and the device in overall is configured to run under the direction of the processor using computer instructions from the memory, the processor and/or its at least one processing core may be considered to be configured to perform said certain actions. The memory may be at least in part comprised in the processor. The memory may be at least in part external to the device 600 but accessible to the device. Control parameters affecting operations in the device may be stored in one or more portions of the memory and used to control operation of the device.
The communications interfaces may provide a communications channel for communications of packets in the network. Examples of the communications interfaces comprise network interface cards and network interface modules that may be connected to the apparatus by means of wired or wireless connections. Wireless connections may comprise Bluetooth and IEEE 802.11 based Wireless Local Area Network (WLAN) connections, for example. The wired connections may comprise data buses, for example. The processor 501 may be operated to control at least some of the communications interfaces 504 by applying at least some of embodiments associated with flood control and illustrated above in connection with
Reference is made to example scenarios of
Next, as illustrated in
In
In an embodiment, a receiving node may in some specific conditions be arranged to enter flood condition by another trigger than the flood control indication, even if a received packet does not include the flood control indication. For example, the flood control (slave) mode may be controlled by a network control function or during a reboot situation to monitor frequency channel usage thoroughly. The trigger may be set e.g. during predefined time period and/or at predefined position/area, the receiving node may be configured to receive data at the second interface duty cycle to ensure high reception capacity e.g. to ensure time-critical data transmission delivery e.g. for healthcare service. The trigger may be set for commercial reasons, such as prearrange adequate reception capacity for local advertisements.
It is to be understood that the embodiments of the invention disclosed are not limited to the particular structures, process steps, or materials disclosed herein, but are extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that terminology employed herein is used for the purpose of describing particular embodiments only and is not intended to be limiting.
Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment.
As used herein, a plurality of items, structural elements, compositional elements, and/or materials may be presented in a common list for convenience. However, these lists should be construed as though a member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary. In addition, various embodiments and example of the present invention may be referred to herein along with alternatives for the various components thereof. It is understood that such embodiments, examples, and alternatives are not to be construed as de facto equivalents of one another, but are to be considered as separate and autonomous representations of the present invention.
Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention.
While the foregoing examples are illustrative of the principles of the present invention in one or more particular applications, it will be apparent to those of ordinary skill in the art that numerous modifications in form, usage and details of implementation can be made without the exercise of inventive faculty, and without departing from the principles and concepts of the invention. Accordingly, it is not intended that the invention be limited, except as by the claims set forth below.
The verbs “to comprise” and “to include” are used in this document as open limitations that neither exclude nor require the existence of also un-recited features. The features recited in depending claims are mutually freely combinable unless otherwise explicitly stated. Furthermore, it is to be understood that the use of “a” or “an”, i.e. a singular form, throughout this document does not exclude a plurality.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20175739 | Aug 2017 | FI | national |
