DESC:TECHNICAL FIELD
[0001] The present invention relates to the field of wireless communication and more particularly the invention relates to dynamic time division multiple access with refresh rate enabled for transmission of periodic data of network nodes in a tactical network environment.

BACKGROUND

[0002] The basis of TDMA is a repeating cycle of transmission and receptions. The time is divided into the period of super frames, with each super frame being very few seconds long. The super frame is further broken down into sub frames, each of which is 100 msec in duration. The time of sub frame is further equally fractioned into segments of 50 time slots in order to use spectrum efficiently. Therefore, the time slot is a fundamental transmission/reception period used by all nodes in the tactical network. A single time slot can be defined as a period of time allocated to a single node for transmission purpose during which all other nodes in the network will be in receive mode of data.
[0003] In US Patent No US8942197B2 invention is generally related to wireless communication and more specifically related to media access control (“MAC”) layer module implementation of a distributed multichannel time division multiple access (TDMA) communication scheme and the dynamic allocation of timeslots and channels.
[0004] In Europe Patent No EP1662678B1 invention relates generally to a time division multiple access (TDMA) communications apparatus for performing TDMA communication in which each frame is divided into a plurality of time slots and every participating station transmits information in allocated slots. More particularly, the invention pertains to slot allocation for a TDMA communication apparatus.
[0005] However there exists a lack of even distribution of time slots across the super frame to meet the timely delivery of data that is crucial in tactical systems. Therefore, there is a need for meeting the refresh rate requirements of the nodes along with the timely delivery of real-time data in tactical environment.
SUMMARY OF THE INVENTION
[0006] An aspect of the present invention is to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below.
[0007] Accordingly, in one aspect of the present invention relates to a method of configuring a dynamic time division multiple access data transmission frame for meeting variable refresh rate requirement of one or more nodes, (200), said method comprising: initializing refresh rate and one or more dynamic time division multiple access parameters of each node of one or more nodes of a tactical wireless network (210), broadcasting and receiving, by each node of the one or more nodes, a dynamic time division multiple access control transmission frame comprising the refresh rate and the one or more dynamic time division multiple access parameters corresponding to each node of the tactical wireless network (220), deriving a global refresh rate and a global one or more dynamic time division multiple access parameters corresponding to the nodes of the tactical wireless network (230), generating the dynamic time division multiple access data transmission frame slot map for allocating slots to the one or more nodes (240) and configuring the dynamic time division multiple access data transmission frame based on the dynamic time division multiple access data transmission frame slot map for meeting the variable refresh rate requirement of the one or more node in the tactical wireless network (250).
[0008] Another aspect of the present invention relates to a system for configuring a dynamic time division multiple access data transmission frame for meeting variable refresh rate requirement of one or more nodes, said system comprising a processor configured to: initialize refresh rate and one or more dynamic time division multiple access parameters of each node of one or more nodes of a tactical wireless network, broadcast and receive, by each node of the one or more nodes, a dynamic time division multiple access control transmission frame comprising the refresh rate and the one or more dynamic time division multiple access parameters corresponding to each node of the tactical wireless network, derive a global refresh rate and a global one or more dynamic time division multiple access parameters corresponding to the nodes of the tactical wireless network, generate a dynamic time division multiple access data transmission frame slot map for allocating slots to the one or more nodes and configure the dynamic time division multiple access data transmission frame based on the dynamic time division multiple access data transmission frame slot map for meeting the variable refresh rate requirement of the one or more node in the tactical wireless network.
[0009] Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The detailed description is described with reference to the accompanying figures.
[0011] FIG. 1 illustrates a dynamic time division multiple access (DTDMA) sub frame structure according to one embodiment of the present invention.
[0012] FIG. 2 illustrates a method of configuring a dynamic time division multiple access data transmission frame for meeting variable refresh rate requirement of one or more nodes according to one embodiment of the present invention.
[0013] FIG. 3 illustrates slot map classification process according to one embodiment of the present invention.
[0014] It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative methods embodying the principles of the present disclosure. Similarly, it will be appreciated that any flow charts, flow diagrams, and the like represent various processes which may be substantially represented in computer readable medium and so executed by a computer or processor, whether or not such computer or processor is explicitly shown.

DETAILED DESCRIPTION
[0015] The present disclosure describes about a method for dynamic time slot allocation to meet variable refresh rate requirement of one or more network nodes. However, the systems and methods are not limited to the specific embodiments described herein. Further, structures and devices shown in the figures are illustrative of exemplary embodiments of the present invention and are meant to avoid obscuring of the present invention. In the following description, for purpose of explanation, specific details are set forth in order to provide an understanding of the present invention. It will be apparent, however, to one skilled in the art that the present disclosure may be practiced without these details. One skilled in the art will recognize that embodiments of the present invention, some of which are described below, may be incorporated into a number of systems.
[0016] It should be noted that the description merely illustrates the principles of the present invention. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present invention. Furthermore, all examples recited herein are principally intended expressly to be only for explanatory purposes to help the reader in understanding the principles of the invention and the concepts contributed by the inventor to furthering the art and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass equivalents thereof.
[0017] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.
[0018] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents. It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. By the term “substantially” it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic is intended to provide.
[0019] The method for dynamic time slot allocation to meet the variable refresh rate requirement of the network nodes has been disclosed. The method comprising initializing refresh rate of a node and dynamic time division multiple access (DTDMA) parameters, broadcasting of refresh rate and DTDMA parameters, collecting refresh rate and DTDMA parameters from all other nodes in the tactical network, deriving global refresh rate and DTDMA parameters applicable for whole tactical network. The method further comprising computating or computing DTDMA time slot map through common distributed function based on the global refresh rate parameters and allocating unused time slots based on the run time data transfer requirements of network node.
[0020] Every node broadcasts own refresh rate and DTDMA parameters along with network control packet. Every node collects refresh rates and dynamic time division multiple access (DTDMA) parameters from all other nodes in the network and forms a common refresh rate and DTDMA parameters applicable for whole network. Every node derives the global refresh rate and DTDMA parameters applicable for the whole network based on the network control packets received from the neighbours or neighbouring nodes. Every node applies common distributed function on global DTDMA flags and derives a common slot map for meeting the refresh rate requirements of network nodes applicable for that cycle. adaptive allocation of time slots is done based on the run time data transfer requests from the mobile units.
[0021] FIG. 1 explains the structure of dynamic time division multiple access (DTDMA) sub frame of 100 ms duration according to one embodiment of the present invention. It is divided into individual time slots of Tslot duration. The concept of sub frames is devised to optimize the network data latency in a way that each node gets a chance at least once in 100 msec irrespective of the number of nodes presence in the tactical network. The definition of sub frame also enables the variable refresh rate of the tactical network. Variable refresh rate is the rate at which a tactical network node requires to update the status to the other nodes in the network.
[0022] FIG. 2 illustrates a method of configuring a dynamic time division multiple access data transmission frame for meeting variable refresh rate requirement of one or more nodes according to one embodiment of the present invention.
[0023] The figure illustrates a method of configuring a dynamic time division multiple access data transmission frame for meeting variable refresh rate requirement of one or more nodes (200), the method comprising few steps: initializing refresh rate and one or more dynamic time division multiple access parameters of each node of one or more nodes of a tactical wireless network (210), broadcasting and receiving, by each node of the one or more nodes, a dynamic time division multiple access control transmission frame comprising the refresh rate and the one or more dynamic time division multiple access parameters corresponding to each node of the tactical wireless network (220), deriving a global refresh rate and a global one or more dynamic time division multiple access parameters corresponding to the nodes of the tactical wireless network (230), generating a dynamic time division multiple access data transmission frame slot map for allocating slots to the one or more nodes (240) and configuring the dynamic time division multiple access data transmission frame based on the dynamic time division multiple access data transmission frame slot map for meeting the variable refresh rate requirement of the one or more node in the tactical wireless network (250).
[0024] The method further comprises allocating one or more idle time slots to a node of one or more nodes of the tactical wireless network based on a run time requirement of the node for data transfer. The dynamic time division multiple access data transmission frame is a super frame comprises plurality of sub-frames. Each of the plurality of sub-frames comprises plurality of time slots.
[0025] The dynamic time division multiple access data transmission frame comprises one or more dedicated access slots, one or more polling access slots, one or more dedicated reallocation slots, and one or more contention slots.
[0026] Each slot of the one or more dedicated access slots is assigned to a node based on corresponding node identifier. The one or more polling access slots are shared by the nodes of the tactical wireless network for digitized voice related communication. The one or more dedicated reallocation slots are assigned to the nodes of the tactical wireless network for communication of high priority data and variable refresh rate requirement of the tactical wireless network. The contention slots are dynamically assigned based on the need of the nodes of the tactical wireless network.
[0027] The dynamic time division multiple access control transmission frame comprises one or more network control packets. The one or more network control packets comprises a refresh rate corresponding to each node and one or more dynamic time division multiple access parameters corresponding to each node. The global refresh rate is a common refresh rate across the tactical wireless network. The global dynamic time division multiple access parameters is common dynamic time division multiple access parameters across the tactical wireless network. The generation of slot map is based on a hash function of the number of slots to be allocated for the one or more nodes of the tactical wireless network.
[0028] The one or more time slots of the dynamic time division multiple access data transmission frame are adaptively allocated based on run time data transfer requests from one or more nodes of the tactical wireless network. The nodes of the tactical wireless network are synchronized with respect to time based on one pulse per second timing.
[0029] In another embodiment, the present invention relates to a system for configuring a dynamic time division multiple access data transmission frame for meeting variable refresh rate requirement of one or more nodes, said system comprising a processor configured to: initialize refresh rate and one or more dynamic time division multiple access parameters of each node of one or more nodes of a tactical wireless network, broadcast and receive, by each node of the one or more nodes, a dynamic time division multiple access control transmission frame comprising the refresh rate and the one or more dynamic time division multiple access parameters corresponding to each node of the tactical wireless network, derive a global refresh rate and a global one or more dynamic time division multiple access parameters corresponding to the nodes of the tactical wireless network, generate a dynamic time division multiple access data transmission frame slot map for allocating slots to the one or more nodes and configure the dynamic time division multiple access data transmission frame based on the dynamic time division multiple access data transmission frame slot map for meeting the variable refresh rate requirement of the one or more node in the tactical wireless network.
[0030] FIG. 3 explains the different types of slot-map allocation process based on the requirement of participating nodes during run time environment.
[0031] The dynamic time division multiple access (DTDMA) method uses global positioning system (GPS) based 1pps for time synchronization of mobile nodes in presence of GPS, or a co-operative time synchronization mechanism in GPS denied environment. It uses the control slots for exchanging configuration parameters, these DTDMA parameters are used in computation of dynamic slot allocation in a co-operative and coordinated manner among the nodes present in the network. A common distributed function is used for dynamic allotment of time slots.
[0032] The dynamic time division multiple access (DTDMA) method divides the time into super frames of two second each, and a super frame is divided into sub frames of 100 ms each. A sub frame is further divided into individual time slots with predetermined slot time of Tslot.
[0033] All the time slots in the sub frame are classified in to four pools, the time slots in the first pool are statically allotted to the nodes in a predetermined manner, the time slots from the second pool are called as polling access slots, the time slots from the third pool are called as dedicated re-allocation pool to meet the variable network refresh rate of participating network nodes, which is larger than the other pools in the sub-frame, and the time slots from the fourth pool are called as contention slots that are allotted in a dynamic manner based on the data requirement of the nodes. In a scenario where there is one node broadcasting an image file in the network shall be allotted all the time slots from the contention pool.
[0034] Time slots in a sub frame are classified in four categories as dedicated access slots, polling access slots, dedicated reallocation slots, and contention slots. The dedicated access slot is a slot that corresponds to a node based on the node ID. Each node in a sub network is assigned a node ID. Wherein, the definition of sub network is given as a group of maximum of N mobile nodes. These nodes can communicate to each other either in direct hop or in multi hop link topology depending on relative navigational position of them. Due to random and dynamic joining or leaving nature of the mobile nodes, each node is assigned one dedicated slot reservation according to its node ID irrespective of presence of the node in the sub network. This access mode guarantees no transmission conflicts in a DTDMA network.
[0035] The polling access slots are a category of slots assigned for digitized voice in tactical communications. Since tactical voice is of highest priority in nature, slots are dedicated for the use. However, the polling access slots are not allocated to a specific node. Polling access slots are shared by all nodes. Each node receives in these slots unless the Push-to-Talk button is selected. Upon selection of Push-to-Talk the node resets to transmit digital voice data. It is possible for two or more nodes to attempt to transmit on digital voice simultaneously, but the protocol recommends listening first before speaking. It ensures that most likely you don’t transmit over the top of another conversation.
[0036] The dedicated reallocation slots are a category of slots assigned to all the member nodes present in the network. The slot allocation distributed method, which runs locally in every node ensures the allocation of slots to itself as well as to others based on the refresh rate requirements of participating network nodes through network control packets received from neighbours. The significance of the logic is that every node does have a variable number of randomly indexed slots assigned to it to use in high priority data viz. situational awareness message, fixed or variable format message or any other kind of emergency message. It also ensures the variable Refresh Rate requirement for the sub network.
[0037] The contention slots are a category of slots that are fully dynamic in nature. The allocation itself is in line with node's need while ensuring collision free packet transmission. Any member node can do request for additional number of slots according to type and volume of data that need to be sent. The number of additional slots assignment depends on the number of nodes present in the sub network as well as the volume of unused slots present during that super frame cycle. The protocol also includes need of slot release signal broadcasted by the user after completing its transmission.
[0038] The dynamic time division multiple access (DTDMA) method uses the control slots for exchanging configuration parameters. The DTDMA parameters are used in computation of dynamic slot allocation to meet the refresh rate requirement in a co-operative and coordinated manner among the nodes present in the tactical network. A common distributed function is used for dynamic allotment of time slots.
[0039] The initial few slots are allotted statically to the nodes for topology/control information exchange. The remaining or the next few slots are allotted based on the variable network refresh rate requirement of network nodes and the leftover slots if at all, are allotted adaptively based on the data transfer requirement of the mobile units. Where Hash function for generating slot map uses is
y=H(x)
where H is a hash function, y = node id, and x=no. of slot to be allocated.
[0040] The variable refresh rate method using dynamic time division multiple access (DTDMA) method is used for meeting the refresh rate requirement of nodes in the network. The method also ensures efficient utilization and sharing of network bandwidth, in which the time is divided into segments of time frames in order to use spectrum efficiently. Each time slot is the fundamental transmission/reception period used by all nodes in a network. A single time slot can be defined as a period of time allocated to a single node for transmission purpose during which all other nodes in the network will be in receive mode of data. During this time slot allocation process each node will be allocated with 10 time-slots per second with 10 Hz network refresh rate.
[0041] It will be readily apparent in different embodiments that the various methods, algorithms, and computer programs disclosed herein are implemented on non-transitory computer readable storage media appropriately programmed for computing devices. The non-transitory computer readable storage media participate in providing data, for example, instructions that are read by a computer, a processor or a similar device. In different embodiments, the “non-transitory computer readable storage media” also refer to a single medium or multiple media, for example, a centralized database, a distributed database, and/or associated caches and servers that store one or more sets of instructions that are read by a computer, a processor or a similar device. The “non-transitory computer readable storage media” also refer to any medium capable of storing or encoding a set of instructions for execution by a computer, a processor or a similar device and that causes a computer, a processor or a similar device to perform any one or more of the methods disclosed herein. Common forms of the non-transitory computer readable storage media comprise, for example, a floppy disk, a flexible disk, a hard disk, magnetic tape, a laser disc, a Blu-ray Disc® of the Blu-ray Disc Association, any magnetic medium, a compact disc-read only memory (CD-ROM), a digital versatile disc (DVD), any optical medium, a flash memory card, punch cards, paper tape, any other physical medium with patterns of holes, a random access memory (RAM), a programmable read only memory (PROM), an erasable programmable read only memory (EPROM), an electrically erasable programmable read only memory (EEPROM), a flash memory, any other memory chip or cartridge, or any other medium from which a computer can read.
[0042] The term “processor” refers to any one or more microprocessors, central processing unit (CPU) devices, finite state machines, computers, microcontrollers, digital signal processors, logic, a logic device, an electronic circuit, an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a chip, etc., or any combination thereof, capable of executing computer programs or a series of commands, instructions, or state transitions. The processor may also be implemented as a processor set comprising, for example, a general purpose microprocessor and a math or graphics co-processor. The method of configuring a dynamic time division multiple access data transmission frame for meeting variable refresh rate requirement of one or more nodes disclosed herein is not limited to employing a processor. The method may also employ a controller or a microcontroller.
[0043] Those skilled in this technology can make various alterations and modifications without departing from the scope and spirit of the invention. Therefore, the scope of the invention shall be defined and protected by the following claims and their equivalents.
[0044] FIGS. 1-3 are merely representational and are not drawn to scale. Certain portions thereof may be exaggerated, while others may be minimized. FIGS. 1-3 illustrate various embodiments of the invention that can be understood and appropriately carried out by those of ordinary skill in the art.
[0045] In the foregoing detailed description of embodiments of the invention, 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 invention require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus, the following claims are hereby incorporated into the detailed description of embodiments of the invention, with each claim standing on its own as a separate embodiment.
[0046] It is understood that the above description is intended to be illustrative, and not restrictive. It is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined in the appended claims. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein,” respectively.

,CLAIMS:

1. A method of configuring a dynamic time division multiple access data transmission frame for meeting variable refresh rate requirement of one or more nodes (200), said method comprising:
initializing refresh rate and one or more dynamic time division multiple access parameters of each node of one or more nodes of a tactical wireless network (210);
broadcasting and receiving, by each node of the one or more nodes, a dynamic time division multiple access control transmission frame comprising the refresh rate and the one or more dynamic time division multiple access parameters corresponding to each node of the tactical wireless network (220);
deriving a global refresh rate and a global one or more dynamic time division multiple access parameters corresponding to the nodes of the tactical wireless network (230);
generating a dynamic time division multiple access data transmission frame slot map for allocating slots to the one or more nodes (240); and
configuring the dynamic time division multiple access data transmission frame based on the dynamic time division multiple access data transmission frame slot map for meeting the variable refresh rate requirement of the one or more node in the tactical wireless network (250).

2. The method as claimed in claim 1, further comprising allocating one or more idle time slots to a node of one or more nodes of the tactical wireless network based on a run time requirement of the node for data transfer.

3. The method as claimed in claim 1, wherein the dynamic time division multiple access data transmission frame is a super frame comprises plurality of sub-frames.

4. The method as claimed in claim 3, wherein the each of the plurality of sub-frames comprises plurality of time slots.

5. The method as claimed in claim 1, wherein the dynamic time division multiple access data transmission frame comprises one or more dedicated access slots, one or more polling access slots, one or more dedicated reallocation slots, and one or more contention slots.

6. The method as claimed in claim 5, wherein each slot of the one or more dedicated access slots is assigned to a node based on a corresponding node identifier.

7. The method as claimed in claim 5, wherein the one or more polling access slots are shared by the nodes of the tactical wireless network for digitized voice related communication.

8. The method as claimed in claim 5, wherein the one or more dedicated reallocation slots are assigned to the nodes of the tactical wireless network for communication of high priority data and variable refresh rate requirement of the tactical wireless network.

9. The method as claimed in claim 5, wherein the contention slots are dynamically assigned based on the need of the nodes of the tactical wireless network.

10. The method as claimed in claim 1, wherein the dynamic time division multiple access control transmission frame comprises one or more network control packets.

11. The method as claimed in claim 10, wherein the one or more network control packets comprises a refresh rate corresponding to each node and one or more dynamic time division multiple access parameters corresponding to each node.

12. The method as claimed in claim 1, wherein the global refresh rate is a common refresh rate across the tactical wireless network and the global dynamic time division multiple access parameters is common dynamic time division multiple access parameters across the tactical wireless network.

13. The method as claimed in claim 1, wherein the generation of slot map is based on a hash function of the number of slots to be allocated for the one or more nodes of the tactical wireless network.

14. The method as claimed in claim 1, wherein one or more time slots of the dynamic time division multiple access data transmission frame are adaptively allocated based on run time data transfer requests from one or more nodes of the tactical wireless network.

15. The method as claimed in claim 1, wherein the nodes of the tactical wireless network are synchronized with respect to time based on one pulse per second timing.

16. A system for configuring a dynamic time division multiple access data transmission frame for meeting variable refresh rate requirement of one or more nodes, said system comprising a processor configured to:
initialize refresh rate and one or more dynamic time division multiple access parameters of each node of one or more nodes of a tactical wireless network;
broadcast and receive, by each node of the one or more nodes, a dynamic time division multiple access control transmission frame comprising the refresh rate and the one or more dynamic time division multiple access parameters corresponding to each node of the tactical wireless network;
derive a global refresh rate and a global one or more dynamic time division multiple access parameters corresponding to the nodes of the tactical wireless network;
generate a dynamic time division multiple access data transmission frame slot map for allocating slots to the one or more nodes; and
configure the dynamic time division multiple access data transmission frame based on the dynamic time division multiple access data transmission frame slot map for meeting the variable refresh rate requirement of the one or more node in the tactical wireless network.