Claims:
1. A method for a centralized messaging service, comprising:
receiving, by a source central radio (102-s), a first set of frames associated with a message from a source terminal radio (106-s);
transmitting, by the source central radio (102-s), one of:
an acknowledgement signal to the source terminal radio (106-s) upon receiving the first set of frames; or
a request for retransmission of one or more frames upon identifying missing of the one or more frames from the first set of frames;
generating, by the source central radio (102-s), the message upon receiving the first set of frames;
transmitting, by the source central radio (102-s), the message to a server (104), wherein the server (104) comprising:
identifying a destination central radio (102-d) associated with the message, wherein the destination central radio (102-d) comprising:
receiving the message from the server (104);
dividing the message into a second set of frames based on N bytes of the message; and
transmitting the second set of frames associated with the message to a destination terminal radio (106-d).

2. The method as claimed in claim 1, comprising:
receiving, by the source Human based machine interface (HMI) device, a message request from the source terminal radio (106-s);
composing, the message by the source Human based machine interface (HMI) device;
sending, the message by the source Human based machine interface (HMI) device to the source terminal radio (106-s); and
transmitting, by the source terminal radio (106-s), the first set of frames associated with the message to the source central radio (102-s), wherein the first set of frames are based on N bytes of the message associated with an air transmit burst.

3. The method as claimed in claim 1, wherein the request for retransmission is transmitted based on:
storing, by the source central radio (102-s), an end of packet and a length of packet associated with the set of frames;
checking, by the source central radio (102-s), a frame sequence number associated with each frame from the first set of frames upon storing the length of packet and the end of packet;
identifying, by the source central radio (102-s), the one or more frames missing from the first set of frames based on the frame sequence number, the end of packet and the length of packet; and
transmitting, by the source central radio (102-s), the request for retransmission to the source terminal radio (106-s) based on the identification.

4. The method as claimed in claim 1, wherein the destination terminal radio (106-d) comprising:
transmitting an acknowledgement signal to the destination central radio (102-d) upon receiving the second set of frames; or
transmitting a request for retransmission of one or more frames upon identifying missing of the one or more frames from the second set of frames.

5. The method as claimed in claim 1, wherein the destination terminal radio (106-d) comprising:
storing an end of packet associated with the second set of frames;
checking a frame sequence number associated with each frame from the second set of fame upon storing the end of packet;
identifying the one or more frames missing from the second set of frames based on the sequence number and the end of packet; and
transmitting the request for retransmission to the destination central radio (102-d) based on the identification.

6. The method as claimed in claim 1, comprising displaying, by the destination terminal radio (106-d), the message to a user using a destination Human based Machine Interface (HMI) device.

7. The method as claimed in claim 1, comprising implementing a randomized beacon transmission algorithm at the source central radio.

8. A system for a centralized messaging service, comprising:
a source terminal radio (106-s) coupled to a source central radio (102-s);
a destination terminal radio (106-d) coupled to a destination central radio (102-d); and
a server (104), wherein the server (104) is coupled to the source central radio (102-s) and the destination central radio (102-d);
further comprising:
a receiving module (304) configured to receive a first set of frames associated with a message from a source terminal radio (106-s);
a transmission module (306) configured to transmit one of:
an acknowledgement signal to the source terminal radio (106-s) upon receiving the first set of frames; or
a request for retransmission of one or more frames upon identifying missing of the one or more frames from the first set of frames;
a generation module (308) configured to generate the message upon receiving the first set of frames;
the transmission module (306) configured to transmit the message to the server (104), wherein the server (104) comprising:
an identification module (310) to identify the destination central radio (106-d) associated with the message, wherein the destination central radio (102-d) comprising:
the receiving module (304) configured to:
receive the message from the server (104); and
divide the message into a second set of frames based on N bytes of the message; and
the transmission module (306) configured to transmit the second set of frames associated with the message to a destination terminal radio (106-d).

9. The system as claimed in claim 8, configured to:
receive a message request from the source central radio (102-s);
compose a message using a source Human based machine interface (HMI) device; and
transmit the first set of frames associated with the message to the source central radio (102-s), wherein the first set of frames are based on N bytes of the message associated with air transmit burst.

10. The system as claimed in claim 8, wherein the request for retransmission is transmitted based on:
storing, by the source central radio (102-s), an end of packet and a length of packet associated with the set of frames;
checking, by the source central radio (102-s), a frame sequence number associated with each frame from the first set of frames upon storing the length of packet and the end of packet;
identifying, by the source central radio (102-s), the one or more frames missing from the first set of frames based on the frame sequence number, the end of packet and the length of packet; and
transmitting, by the source central radio, the request for retransmission to the source terminal radio (106-s) based on the identification.

11. The system as claimed in claim 8, wherein the destination terminal radio (106-d) comprising:
transmitting an acknowledgement signal to the destination central radio (102-d) upon receiving the second set of frames; or
transmitting a request for retransmission of one or more frames upon identifying missing of the one or more frames from the second set of frames.

12. The system as claimed in claim 8, wherein the destination terminal radio (106-d) comprising:
storing an end of packet associated with the second set of frames;
checking a frame sequence number associated with each frame from the second set of fame upon storing the end of packet;
identifying the one or more frames missing from the second set of frames based on the frame sequence number and the end of packet; and
transmitting the request for retransmission to the destination central radio (102-d) based on the identification.

13. The system as claimed in claim 8, configured to display, by the destination terminal radio (106-d), the message to a user using a destination Human based Machine Interface (HMI) device.
, Description: FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
&
THE PATENTS RULES, 2003

COMPLETE SPECIFICATION
[SEE SECTION 10, RULE 13]

A SYSTEM AND METHOD FOR A CENTRALISED MESSAGING SERVICE

BHARAT ELECTRONICS LIMITED
WITH ADDRESS:
OUTER RING ROAD, NAGAVARA, BANGALORE 560045, KARNATAKA, INDIA

THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.
TECHNICAL FIELD
[0001] The present invention relates generally to systems and methods for a centralized messaging service.
BACKGROUND
[0002] US6959194B2 discloses a messaging server but do not consider the centralized coordination among the users. The existing system does not consider a low probability of detection of transmitted RF burst streams. Further, US7197324B2 discloses a messaging network connected to an internet network.
[0003] Generally, data may be missed during transmission of packets from one terminal to another terminal in a network. Thus, erroneous packets may be transmitted. Also, it may not be possible to identify such errors in the packet. In case of retransmission, whole packet must be retransmitted from one terminal to another terminal. Hence, it increases a time for transmission.
[0004] Therefore, there is a need of a system and method which solves the above defined problems and can provide an efficient system and method for a centralized messaging service.
[0005] In order to address the requirement, a system in the present invention is realized by a TDMA based centralized messaging service over a radio Network.
SUMMARY
[0006] This summary is provided to introduce concepts related to systems and methods for a centralized messaging service. This summary is neither intended to identify essential features of the present invention nor is it intended for use in determining or limiting the scope of the present invention.
[0007] In an embodiment of the present invention, a method for a centralized messaging service is provided. The method includes receiving, by a source central radio, a first set of frames associated with a message from a source terminal radio. The source central radio comprises transmitting one of an acknowledgement signal to the source terminal radio upon receiving the first set of frames, or a request for retransmission of one or more frames upon identifying missing of the one or more frames from the first set of frames. Upon transmission, the source central radio comprises generating the message upon receiving the first set of frames. The source central radio comprises transmitting the message to a server. The server comprises of identifying a destination central radio associated with the message. The destination central radio comprises receiving the message from the server. The destination central radio comprises dividing the message into a second set of frames based on N bytes of the message. The destination central radio comprises transmitting the second set of frames associated with the message to a destination terminal radio.
[0008] In another embodiment of the present invention, a system for a centralized messaging service is provided. The system includes a source terminal radio coupled to a source central radio, a destination terminal radio coupled to a destination central radio, and a server. The server is coupled to the source central radio and the destination central radio. The system further comprising a receiving module configured to receive a first set of frames associated with a message from a source terminal radio. The system comprising a transmission module configured to transmit one of an acknowledgement signal to the source terminal radio upon receiving the first set of frames, or a request for retransmission of one or more frames upon identifying missing of the one or more frames from the first set of frames. The system comprising a generation module configured to generate the message upon receiving the first set of frames. The system includes the transmission module configured to transmit the message to a server. The server comprising an identification module configured to identify a destination central radio associated with the message. The destination central radio comprising the receiving module configured to receive the message from the server and divide the message into a second set of frames based on N bytes of the message. The destination central radio includes the transmission module to transmit the second set of frames associated with the message to a destination terminal radio.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
[0009] The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to reference like features and modules.
[0010] Figure 1 illustrates a block diagram depicting a system for a centralized messaging service, according to an embodiment of the present invention.
[0011] Figure 2 illustrates a block diagram depicting a connection between terminal radios, central radios, and a server, according to an embodiment of the present invention.
[0012] Figure 3A and 3B illustrates a system for a centralized messaging service, according to an embodiment of the present invention.
[0013] Figure 4 illustrates a flow diagram depicting a communication between a source terminal radio and a source central radio, according to an embodiment of the present invention.
[0014] Figure 5 illustrates a flow diagram depicting a retransmission logic for a source central radio, according to an embodiment of the present invention.
[0015] Figure 6 illustrates a flow diagram depicting a communication between a destination central radio and a destination terminal radio, according to an embodiment of the present invention.
[0016] Figure 7 illustrates a flow diagram depicting a retransmission logic for a destination terminal radio, according to an embodiment of the present invention.
[0017] Figure 8 illustrates a flowchart depicting a method for a centralized messaging service, according to an embodiment of the present invention.
[0018] Figure 9A illustrates a message format at a source terminal radio, according to an embodiment of the present invention.
[0019] Figure 9B illustrates a message format at a destination central radio, according to an embodiment of the present invention.
[0020] It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative systems embodying the principles of the present invention. 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
[0021] The various embodiments of the present invention provide a system and method for a centralized messaging service.
[0022] In the following description, for purpose of explanation, specific details are set forth to provide an understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention 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 several systems.
[0023] 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.
[0024] Furthermore, connections between components and/or modules within the figures are not intended to be limited to direct connections. Rather, these components and modules may be modified, re-formatted or otherwise changed by intermediary components and modules.
[0025] References in the present invention to “an embodiment” or “another embodiment” mean that a particular feature, structure, characteristic, or function described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase “in an embodiment” in various places in the specification are not necessarily all referring to the same embodiment. The phrase “embodiment of the present invention” used in the present invention may refer to various embodiments of the present invention.
[0026] The present invention provides a system and method for a centralized messaging service.
[0027] In an embodiment of the present invention, a method for a centralized messaging service is provided. The method includes receiving, by a source central radio, a first set of frames associated with a message from a source terminal radio. The source central radio comprises transmitting one of an acknowledgement signal to the source terminal radio upon receiving the first set of frames, or a request for retransmission of one or more frames upon identifying missing of the one or more frames from the first set of frames. Upon transmission, the source central radio comprises generating the message upon receiving the first set of frames. The source central radio comprises transmitting the message to a server. The server comprises identifying a destination central radio associated with the message. The destination central radio comprises receiving the message from the server. The destination central radio comprises dividing the message into a second set of frames based on N bytes of the message. The destination central radio comprises transmitting the second set of frames associated with the message to a destination terminal radio.
[0028] In an exemplary embodiment of the present invention, the method includes receiving, by the source Human based machine interface (HMI) device, a message request from the source terminal radio (106-s). The method includes composing, the message by the source Human based machine interface (HMI) device, and sending, the message by the source Human based machine interface (HMI) device to the source terminal radio (106-s). The method includes transmitting, by the source terminal radio (106-s), the first set of frames associated with the message to the source central radio (102-s), wherein the first set of frames are based on N bytes of the message associated with an air transmit burst.

[0029] In another exemplary embodiment of the present invention, the request for retransmission is transmitted based on storing, by the source central radio, an end of packet and a length of packet associated with the set of frames, checking, by the source central radio, a frame sequence number associated with each frame from the first set of frames upon storing the length of packet and the end of packet, identifying, by the source central radio, the one or more frames missing from the first set of frames based on the frame sequence number, the end of packet and the length of packet, and transmitting, by the source terminal radio, the request for retransmission to the source terminal radio based on the identification.
[0030] In yet another exemplary embodiment of the present invention, the destination terminal radio comprising transmitting an acknowledgement signal to the destination central radio upon receiving the second set of frames or transmitting a request for retransmission of one or more frames upon identifying missing of the one or more frames from the second set of frames.
[0031] In yet another exemplary embodiment of the present invention, the destination terminal radio comprising storing an end of packet associated with the second set of frames. The destination terminal radio checking a frame sequence number associated with each frame from the second set of fame upon storing the end of packet. The destination terminal radio identifying the one or more frames missing from the second set of frames based on the sequence number and the end of packet; and transmitting the request for retransmission to the destination central radio based on the identification.
[0032] In yet another exemplary embodiment of the present invention, the method comprising displaying, by the destination terminal radio, the message to a user using a destination Human based Machine Interface (HMI) device.
[0033] In another embodiment of the present invention, a system for a centralized messaging service is provided. The system includes a source terminal radio coupled to a source central radio, a destination terminal radio coupled to a destination central radio, and a server. The server is coupled to the source central radio and the destination central radio. The system further comprising a receiving module configured to receive a first set of frames associated with a message from a source terminal radio. The system comprising a transmission module configured to transmit one of an acknowledgement signal to the source terminal radio upon receiving the first set of frames, or a request for retransmission of one or more frames upon identifying missing of the one or more frames from the first set of frames. The system comprising a generation module configured to generate the message upon receiving the first set of frames. The system includes the transmission module configured to transmit the message to a server. The server comprising an identification module configured to identify a destination central radio associated with the message. The destination central radio comprising the receiving module configured to receive the message from the server and divide the message into a second set of frames based on N bytes of the message. The destination central radio includes the transmission module configured to transmit the second set of frames associated with the message to a destination terminal radio.
[0034] In an exemplary embodiment of the present invention, the system configured to receive a message request from the source central radio, compose the message using a source Human based machine interface (HMI) device, and transmit the first set of frames associated with the message to the source central radio, wherein the first set of frames are based on N bytes of message associated with air transmit burst.
[0035] In another exemplary embodiment of the present invention, the request for retransmission is transmitted based on storing, by the source central radio, an end of packet and a length of packet associated with the set of frames, checking, by the source central radio, a frame sequence number associated with each frame from the first set of frames upon storing the length of packet and the end of packet, identifying, by the source central radio, the one or more frames missing from the first set of frames based on the frame sequence number, and transmitting, by the source terminal radio, the request for retransmission to the source terminal radio based on the identification.
[0036] In yet another exemplary embodiment of the present invention, the destination terminal radio comprising transmitting an acknowledgement signal to the destination central radio upon receiving the second set of frames or transmitting a request for retransmission of one or more frames upon identifying missing of the one or more frames from the second set of frames.
[0037] In yet another exemplary embodiment of the present invention, the destination terminal radio comprising storing an end of packet associated with the second set of frames, checking a frame sequence number associated with each frame from the second set of fame upon storing the end of packet, identifying the one or more frames missing from the second set of frames based on the frame sequence number and the end of packet, and transmitting the request for retransmission to the destination central radio based on the identification.
[0038] In yet another exemplary embodiment of the present invention, the system configured to display, by the destination terminal radio, the message to a user using a destination Human based Machine Interface (HMI) device.
[0039] Referring to Figure 1, a block diagram depicting a system (100) for a centralized messaging service is shown according to an embodiment of the present invention. In an embodiment, figure 1 depicts a centralized radio (102), a messaging server (104) and a set of terminal radios referred as terminals 1, 2, 3…100. Each terminal radio from the set of terminal radios may be referred as 106-1, 106-2, …106-n.
[0040] In one aspect, the messaging service over a radio network is having a centralized architecture to support distributed users in the field.
[0041] The centralized radio (102) is deployed at an elevated location. The centralized radio (102) can communicate with the set of terminal radios (106-1, 106-2, … 106-n) deployed in the field. The centralized radio (102) is referred as a central radio.
[0042] The central radio (102) is configured to receive messages from terminal radios (106-1. 106-2, …106-n), and forward the messages to the messaging server (104) for processing. The central radio (102) is configured to transmit messages from the messaging server (104) to the terminal radios (106-1, 106-2,…106-n). The terminal radios (106-1, 10602, …106-n) uses VHF or UHF frequency bands to communicate with the centralized radio (102). The messaging server (104) uses a wired communication or a wireless communication to transmit or receive messages from the central radio (102). In one aspect, depending on number of the terminal radios (106-1, 106-2, …106-n) in the network, the central radio (102) can be a single radio catering for all users or multiple radios catering group of terminals.
[0043] The messaging server (104) is light weight and can be installable on Operating System (OS) based human machine interface (HMI) kind of platforms. The messaging server (104) is configured to support functionalities such as message transmission, forwarding, storing, location awareness and others. The messaging server (104) may be referred as a server.
[0044] In one embodiment, the terminal radios (106-1, 106-2, …106-n) consists of two components a Human based machine interface (HMI) and a radio.
[0045] The HMI may include, but is not limited to, a smartphone with a messaging application. In one example, a user will compose, send, and receive a message from the messaging application. It is possible to communicate with the radio via a wired communication or a wireless communication. The messaging application is configured to transmit or receive an information to the radio via the interface.
[0046] The radio is configured to interface with the HMI based application. All parameters of the radio and the message received or transmitted on the radio will be displayed on the application of the smartphone. In one aspect, an authentication mechanism between the smartphone and the radio is developed to prevent an unauthorized use of the radio with other smartphones. The transmission of the radio is designed to have a low duration transmission over an air.
[0047] In one embodiment, the system (100) uses a random algorithm to allow the terminal radios to transmit messages or frames in the network randomly. The random algorithm helps to determine the terminal radio that will transmit, and the terminal radio that will receive.
[0048] In one aspect, the central radio (102) generates random numbers between 1 and 2000 time slots. The time slots are used for selection of beacon transmission slots for users in each frequency. In one example, the first 100 numbers, from the random numbers generated, are used for selection of the beacon transmission slots for a user 1 in each frequency group, next 100 numbers for a user 2 in each frequency group, like wise other user data in a set of 100 time slots.
[0049] In the aspect, number of time slots to generate depends on a message length and a number of terminal users in a group. Depending on a throughput achievable, a number of characters transmitted per time slot will vary. The random algorithm allows different radios to transmit at different time randomly as per algorithm implemented at the server (104). Table 1 shows transmission of messaging by different radio at different instant.
Table 1: Transmission of Messaging by different Radio at different instant
Timing T1 T2 T3 T4 T5 T6 T7 ----- ------- TN
Radio Radio 1 Radio 5 Idle Radio 8 Radio 1 Radio 4 ---- ----- ------ Radio X
[0050] In one aspect, the messaging service over the air frame consists of X bit of preamble, Y bit of sync word, M bit of payload and Z bit of CRC making it to the total of (X+Y+M+Z) bit long. By transmitting the frames over the air at a data rate greater than (X+Y+M+Z) Kbps makes it low duration typically in range of millisecond or microseconds. Table 2 shows the typical over the air burst structure.
Table 2: Typical over the air burst structure.
Preamble Sync word Payload CRC
X bit Y bit M bit Z bit
[0051] Referring to Figure 2, a block diagram depicting a connection between terminal radios, central radios and a server is shown, according to an embodiment of the present invention.
[0052] In one embodiment, groups of terminal radios (group-1, group-2…group-n) are formed. Each group may comprise n number of terminal radios. In one example, group-1 (201) may comprise terminal radios 10-19, group-2 (204) may comprise terminal radios 20-29, and likewise group-n (206) may comprise terminals n0-n9.
[0053] Each group is connected to the central radio. In other words, the terminal radios from the groups are connected to the central radio. In one embodiment, the group-1 is connected to the central radio CR1 (202), group-2 is connected to the central radio CR2 (205), group-n is connected to the central radio CRN (207), and the like. The central radios CR1, CR2…CRN are further connected to the server (203).
[0054] In one aspect, the central radio is using First in First Out (FIFO) algorithm to process the messages received from the terminal radios. Using the FIFO algorithm, the central radio is configured to process the terminal radio for which it receives the message first.
[0055] Referring to figure 3A and 3B, a system for a centralized messaging service is shown, according to an embodiment of the present invention.
[0056] The system includes a source terminal radio (106-s), a destination terminal radio (106-d), a source central radio (102-s), a destination central radio (102-d), and a server (104). The source terminal radio (106-s) is coupled to the source central radio (102-s). The destination terminal radio (106-d) is coupled to the destination central radio (102-d). The source central radio (102-s) and the destination central radio (102-d) are further coupled via the server (104).
[0057] In one exemplary implementation, the source central radio (102-s) receives a message from multiple source terminal radios. The source central radio (102-s) processes the message and transmit the message to the destination terminal radio (106-d) via the server (104) and the destination central radio (106-d).
[0058] The system comprises one or more processors (302). The one or more processors (302) are coupled to a memory (312). In one implementation, the source terminal radio (106-s) comprises a processor from the one or more processors (302), the source central radio (102-s) comprises a processor from the one or more processors (302), the server (104) comprises a processor from the one or more processors (302), the destination terminal radio (106-d) comprises a processor from the one or more processors (302), and the destination central radio (102-d) comprises a processor from the one or more processors (302). The one or more processors (302) may be, but is not limited to, a microprocessor, a microcontroller, a control unit, a processing unit, and the like.
[0059] The memory (312) is configured to store pre-determined parameters and rules related to the centralized messaging service. In an embodiment, the memory (312) can include any computer-readable medium known in the art including, for example, volatile memory, such as static random-access memory (SRAM) and dynamic random-access memory (DRAM), and/or non-volatile memory, such as read only memory (ROM), erasable programmable ROM, flash memories, hard disks, optical disks, and magnetic tapes. The memory (312) also includes a cache memory to work with the system more effectively. In one aspect, the memory (312) can be internal or external based on the complexity of application. For low complexity preferably internal memory or external for other complex applications.
[0060] The system further includes a database (314). The database (314) is configured to store a message, a first set of frames and a second set of frames. In an embodiment, the database (314) can be implemented as, but is not limited to, an enterprise database, a remote database, a local database, and the like. In one embodiment, the database (314) may themselves be located either within the vicinity of each other or may be located at different geographic locations. In another embodiment, the database (314) can be implemented as a single database.
[0061] The one or more processors (302) include a receiving module (304), a transmission module (306), a generation module (308), and an identification module (310).
[0062] The one or more processors (302) control and monitor the functioning of the blocks (304-310). In an embodiment, the one or more processors (302) perform a method for a centralized messaging service.
[0063] In one embodiment, the receiving module (304) is configured to receive the first set of frames. The first set of frames are received from the source terminal radio (106-s).
[0064] In one embodiment, the source terminal radio (106-s) is configured to receive a message request from the source central radio (102-s). Upon receiving the message request, the source terminal radio (106-s) composes the message. The message is composed using a source Human based machine interface (HMI) device. The source HMI device is associated with the source terminal radio (106-s).
[0065] The source terminal radio (106-s) further divides the message into the first set of frames. The message is divide based on N bytes of the message associated with an air transmit burst. Based on the division, the first set of frames are transferred to the source central radio (102-s).
[0066] In one embodiment, over the air, a burst structure from the source terminal radio (106-s) to the source central radio (102-s) will be as per Table 3.
Table 3: Burst structure from the source terminal radio (106-s) to the source central radio (102-s)
Preamble Sync word Payload CRC
X bit Y bit Central radio
ID Frame Sequence
number 1st byte
of Message Nth byte
of Message Z bit
[0067] In one embodiment, the central radio ID indicates a radio ID of the source central radio (102-s). The frame sequence number indicates that 1st N byte of the message will have sequence number as 1, 2nd N bytes of the message will have sequence number as 2 and the like.
[0068] Once the message is received, the transmission module (306) is configured to transmits one of an acknowledgement signal or a request for retransmission to the source terminal radio (106-s).
[0069] In one embodiment, the transmission module (306) checks if each frame from the first set of frames is received or not. The transmission module (306) checks an End of Packet (EOP) and a Length of Packet (LOP) associated with the message. Further, the transmission module (306) analyses the frame sequence number associated with each frame from the first set of frames. Based on the EOP, LOP and the frame sequence number, the transmission module (306) determines one or more frames missing from the first set of frames.
[0070] If the one or more frames are determined, the transmission module (306) is configured to transmit the request for retransmission to the source terminal radio (106-s). The request for retransmission indicates that the one or more frames are missing and hence the source terminal radio (106-s) retransmits the one or more frame. In one example, the request for retransmission indicates the frame sequence number associated with the one or more frames, and the source terminal radio (106-s) retransmits the one or more frames.
[0071] If no frame is missing, the transmission module (306) transmits the acknowledgement signal to the source terminal radio (106-s). The acknowledgment signal indicates that all frames from the first set of frames are received by the source central radio (102-s).
[0072] The generation module (308) is configured to generate the message upon receiving the first set of frames. The message is generated at the source central radio (102-s).
[0073] In one exemplary embodiment, the first set of frames are received. If any frame is missing, the frame missing from the first set of frames is received based on transmission of the request for retransmission. Further, the message is generated using the first set of frames received.
[0074] Upon generation, the transmission module (306) is configured to transmit the message to the server (104).
[0075] Based on the transmission, the identification module (310) is configured to identify the destination terminal radio (106-d) and the destination central radio (102-d). In one embodiment, the destination terminal radio (106-d) is identified based on a destination terminal ID associated with the message. Once the destination terminal radio (106-d) is identified, a central radio to which the destination terminal radio (106-d) is connected is the destination central radio (102-d). In one aspect, the server (104) communicates with the destination terminal radio (106-d) via the destination central radio (102-d).
[0076] Upon identification, the transmission module (306) transmits the message to the destination central radio (102-d).
[0077] Further, the receiving module (304) receives the message. The receiving module (306) divides the message into a second set of frames. The second set of frames are transmitted to the destination terminal radio (106-d). In one aspect, the transmission module (306) transmits the second set of frames.
[0078] The structure of the message from the destination central radio (102-d) to the destination terminal radio (106-d) is as per Table 2.
Table 4: Structure of the message from the destination central radio (102-d) to the destination terminal radio
Preamble Sync word Payload CRC
X bit Y bit Terminal radio
ID Frame Sequence
number 1st byte
of Message Nth byte
of Message Z bit
[0079] In one embodiment, the terminal radio ID indicates the ID the destination terminal radio (106-d). The frame sequence number indicates that 1st N byte of the message will have sequence number as 1, 2nd N bytes of the message will have sequence number as 2 and the like.
[0080] Upon receiving the second set of frames, the transmission module (306) transmits one of the acknowledgement signal or the request for retransmission to the destination central radio (102-d).
[0081] In one embodiment, an end of packet (EOP) associated with second set of frames is stored. Further, the frame sequence number associated with each frame of the second set of frames is checked at the destination terminal radio (106-d). Based on the analysis, one or more frames missing from the second set of frames are identified. Upon identification of the one or more frames, the request for transmission is transmitted to the destination central radio (102-d). In one aspect, the request for retransmission indicates the frame sequence number associated with the one or more frames.
[0082] Once the request for retransmission is received by the destination central radio (102-d), the destination central radio (102-d) retransmits the one or more frames to the destination terminal radio (106-d). In one aspect, the retransmission is possible for only 3 times for each frame.
[0083] If no frame is missing, the transmission module transmits the acknowledgement signal to the destination central radio (102-d). The acknowledgement signal indicates that all frames from the second set of frames are received by the destination terminal radio (106-s).
[0084] Once the second set of frames are received, the message is generated at the destination terminal radio (106-d). Further, the message is displayed to a user using a destination Human based machine interface (HMI) device. The destination HMI device is associated with the destination terminal radio (106-d).
[0085] Referring now to Figure 4, a flow diagram depicting a communication between a source terminal radio and a source central radio is shown, according to an embodiment of the present invention.
[0086] At step (404), a packet request is received by the source terminal radio (106-s) from the source central radio (102-s). In one aspect, the packet request is received by the source Human based machine interface (HMI) device from the source terminal radio(106-s). The packet request may be referred as a message request. Upon receiving the message request, a source Human based machine interface (HMI) device is configured to compose a message.
[0087] At step (406), the source terminal radio (106-s) checks the availability of a packet. The packet may be referred as the message. In other words, the source terminal radio (106-s) may check if the source HMI device has composed the message to transmit or not.
[0088] If the message is not available at the source HMI device, the source terminal radio (106-s) may again request the source HMI device to compose the message. In one aspect, the request for composition of the message may be sent in a predefined time. The request may be a periodic request.
[0089] If the message is composed, the source terminal radio (106-s) is configured to store the message in a local buffer. At step (408), the source terminal radio (106-s) stores the message in the local buffer.
[0090] At step (410), the source terminal radio (106-s) is configured to transmit the message in the form of frames to the source central radio (102-s). In one embodiment, the source terminal radio (106-s) divides the message into a first set of frames based on N bytes of the message. Further, the source terminal radio (106-s) transmits each frame from the first set of frames to the source central radio (102-s) over an air transmit burst.
[0091] At step 412, the source terminal radio (106-s) checks if the transmission is completed or not. In one aspect, the source terminal radio (106-s) receives an acknowledgement signal from the source central radio (102-s) based on the completion of the transmission. In another aspect, the source terminal radio (106-s) may receive a request for retransmission from the source central radio (102-s). The request for retransmission indicates that all frame from the first set of frames is not received by the source central radio and few frames are missing. Upon receiving the request for retransmission, the source terminal radio (106-s) may retransmit the frames missing from the first set of frames.
[0092] At step 414, the source terminal radio (106-s) receives the acknowledgment signal from the source central radio (102-s). Upon receiving the acknowledgement signal, the source terminal radio (106-s) may further start the transmission of another message.
[0093] At step 416, the source terminal radio (106-s) is configured to wait for a defined time to receive the acknowledgement signal. If the acknowledgement signal is not received in the defined time, then the source terminal radio (106-s) considers that the message is not transmitted.
[0094] Referring to Figure 5, a flowchart depicting a retransmission logic for a source central radio is shown, according to an embodiment of the present invention.
[0095] A step 502, a message is composed by a source Human based machine interface (HMI) device at a source terminal radio (106-s).
[0096] In one aspect, a format of the message at the source terminal radio is shown in figure 9A. Referring now to figure 9A, a message format at the source terminal radio is shown, according to an embodiment of the present invention. The message may comprise a start of packet (SOP), a packet originating radio ID, a packet destination radio ID, a length of actual message (LOP), an actual message and an end of the packet (EOP). The message is transmitted over an air transmit burst.
[0097] At step 504, the source terminal radio (106-s) transmits the message to the source central radio (102-s). The source terminal radio (106-s) is configured to transmit a first set of frames associated with the message. In other words, the source terminal radio (106-s) transmits frame by frame message to the source central radio (102-s).
[0098] At step 506, the source central radio (102-s) is configured to store each frame, received from the source terminal radio (106-s), in a buffer.
[0099] At step 508, the source central radio (102-s) is configured to check the End of Packet (EOP) associated with the message upon storing each frame. In one embodiment, the source central radio (102-s) checks if the EOP is greater than 0 or not.
[00100] At step 518, the source central radio (102-s) is configured to check the Length of Packet (LOP) associated with the message. In one embodiment, the source central terminal (102-s) checks if the LOP is greater than 0 or not.
[00101] In one embodiment, the source central radio (102-s) is configured to receive an end_of_packet frame from the source terminal radio (106-s). Upon reception, the source central radio (102-s) increases a num_of_terminal_eop by one. In one aspect, a non-zero value of num_of_terminal_eop needs to get processed for one or more frames missing from the first set of frames.
[00102] In one embodiment, the source central radio (102-s) is configured to maintain two parameters such as a num_terminal_with_length_of_packet and a num_terminal_with_end_of_packet. Once the source central radio (102-s) receives the LOP frame or the EOP frame, the source central radio (102-s) increases the num_terminal_with_length_of_packet or num_terminal_with_end_of_packet by one, respectively.
[00103] In one embodiment, the num_terminal_with_length_of_packet is equal to the num_terminal_with_end_of_packet and both are non-zero. In the embodiment, the source central radio (102-s) received the start of packet, the length of packet and the end of packet from the source terminal radio (106-s). In one aspect, the source central radio (102-) is configured to process the source terminal radio (106-s) for which the source central radio (102-s) got the end of packet first.
[00104] In another embodiment, the num_terminal_with_length_of_packet is greater than the num_terminal_with_end_of_packet and the num_terminal_with_length_of_packet is non-zero. At step 518, the LOP is greater than zero. In the embodiment, the source central radio (102-s) is configured to receive the start of packet, the length of packet but missed the end of packet from the source terminal radio (106-s). The num_terminal_with_length_of_packet will have nonzero value, whereas the num_terminal_with_end_of_packet will have zero value. The source central radio (102-s) is configured to further check an elapsed time since the reception of the start of packet from the source terminal radio (106-s). If the elapsed time is more than a full packet reception time, then the source central radio (102-s) is configured to process the source terminal radio (106-s) for missed packet, else the source central radio (102-s) is configured to wait to elapse the full packet reception time.
[00105] In yet another embodiment, the source central radio missed the length of packet and the end of the packet but received the start of packet from the source terminal radio. In the embodiment, the num_terminal_with_length_of_packet and the num_terminal_with_end_of_packet is zero. The source central radio (102-s) is configured to check for reception of any frame with the start of packet. If any frame is received with the start of packet, then after waiting for the full reception time from the reception of the start of packet, the source central radio (102-s) clears the buffer assigned to the source terminal radio (102-s).
[00106] At step (510), the source central radio (102-s) is configured to receive the first set of frames from the source terminal radio (106-s), when the EOP is greater than zero. In one aspect, the source central radio (102-s) receives the first set of frames, when the EOP is missing but the LOP is greater than zero. In another aspect, the source central radio (102-s) receives the first set of frames, when one of the EOP or the LOP are greater than zero at step (526).
[00107] At step (520), the source central radio (102-s) check for any unprocessed terminal radio, when the LOP is not greater than zero. At step (522), the source central radio (102-s) checks for a timeout. The source central radio (102-s) checks for a time elapsed from the reception of the start of packet. At step (524), if the time elapsed is less than the full packet reception time, then the source central radio (102-s) is configured to wait to elapse the full packet reception time.
[00108] At step (526), the source central radio (102-s) checks if one of the EOP and the LOP is greater than zero, when the time elapsed is more than a full packet reception time. Further, the source central radio (102-s) is configured to receive the message from the source terminal radio (106-s) at the step (510).
[00109] In one embodiment, the full packet reception time for the source central radio (102-s) can be defined as an expected time the source central radio (102-s) will take to receive all frames from the first set of frames with maximum possible length. The full packet reception time can be evaluated using equation 1.
Full packet reception time = maximum_no_frame * sync_interval …equation 1
Wherein,
maximum_no_frame - Maximum length of message/N
sync_interval = Time Interval at which the source terminal radio is getting the sync packet from the source central radio
[00110] In one aspect, single central radio (102-s) has to cater multiple terminal radios, so the central radio maintains two multi-dimensional buffers to store received frame byte and a frame sequence number. Size of multi-dimensional buffer to store the frame sequence number will be given using equation 2.
Size of multi-dimensional buffer to store frame sequence number= [Total no of Terminal] [Maximum no. of frames] …equation 2
[00111] Also, the size of multi-dimensional buffer to store the frame bytes will be given as equation 3.
Size of multi-dimensional buffer to store the frame bytes = [Total no of Terminal] [Maximum packet length] …equation 3
[00112] In one embodiment, once the source central radio (102-s) receives the start of packet, the source central radio (102-s) starts storing the frame byte and the frame sequence number in two different multidimensional array buffers.
[00113] Upon determining the source terminal radio (106-s) that is to be processed, the source central radio (102-2) is configured to process the received frame sequence number from the source terminal radio (106-s).
[00114] At step (514), the source central radio (102-s) is configured to check the frame sequence number. If any sequence number is missing, then the source central radio (102-s) is configured to transmit a request for retransmission to the source terminal radio (106-s). The missing sequence number indicates that one or more frames are missing from the first set of frames. The request for retransmission indicates the retransmission of the one or more frames associated with the missing sequence number frame. At step (530), the source central radio (102-s) is configured to transmit the request for retransmission.
[00115] If no frame is missing, the source central radio (102-s) is configured to transmit the acknowledgement signal to the source terminal radio (106-s). The acknowledgement signal indicates that all frames from the first set of frames are received by the source central radio (102-s). At step (516), the source central radio (102-s) transmits the acknowledgment signal.
[00116] In one aspect, a missed_packet_processing_status indicates that any missed frame processing is going or not in the source central radio (102-s).
[00117] A terminal_under_processing indicates a terminal radio ID whose frames is under processing for the frames missing.
[00118] Once the first set of frames are received, the source central radio (102-s) generates the message from the first set of frames. The source central radio further transmits the message to a server (104).
[00119] In one embodiment, consider that the source terminal radio (106-s) has transmitted all of its frames, then till the reception of the acknowledgment signal from the source central radio (102-s), the source terminal radio (106-s) will not need a sync packet. For better utilization of a time slot, the source central radio (102-s) stops sending the sync frame to the source terminal radio (106-s) under processing. The time slot may be used by the source central radio (102-s) to transmit the retransmission signal to the source terminal radio (106-s) under processing.
[00120] Once the processing of the source terminal radio (106-s) gets completed by the source central radio (102-s), the source central radio (102-s) is configured to reset all buffer allotted to the source terminal radio (106-s).
[00121] Referring now to figure 6, a flow diagram depicting a communication between a destination central radio and a destination terminal radio is shown, according to an embodiment of the present invention.
[00122] At step (602), the destination central radio (102-s) is configured to receive a transmit packet request. The transmit packet request indicates transmission of a message from the destination central radio (102-s) to the destination terminal radio (106-d). In one embodiment, the destination central radio (102-d) receives the message from a server (104).
[00123] At step (604), if the destination central radio (102-d) fails to receive the transmit packet request, then the destination central radio (102-d) is configured to wait for receiving the transmit packet request.
[00124] At step (610), the destination central radio (102-d) transmits the message to the destination terminal radio (106-d). The message may be divided into a second set of frames. Further, each frame from the second set of frames may be transmitted by the destination central radio (102-d) to the destination terminal radio (106-d).
[00125] At step (612), the destination central radio (102-d) is configured to store the message in a buffer.
[00126] At step (614), the destination central radio (106-d) transmits the message to the destination terminal radio (106-d) via air burst. Each frame, from the second set of frames are transmitted via an air transmit burst.
[00127] At step (616), the destination terminal radio (106-d) checks if the transmission is completed or not. In one aspect, the destination terminal radio (106-d) transmits a request for retransmission to the destination central radio (102-d), when the transmission is not completed.
[00128] In one embodiment, if the destination terminal radio (106-d) identifies one or more frames missing from the second set of frames. The destination terminal radio (106-d) transmits the request for retransmission to the destination central radio (102-d).
[00129] At step (606), the destination central radio (102-d) receives an acknowledgement signal from the destination terminal radio (106-d) upon completion of the transmission.
[00130] At step (608), the destination central radio (102-d) is configured to wait for a timeout, when the acknowledgment signal is not received. Based on the timeout, the destination central radio (102-d) receives another transmit packet request for another message.
[00131] Referring now to figure 7, a flow diagram depicting a retransmission logic for a destination terminal radio is shown, according to an embodiment of the present invention.
[00132] At step (702), a destination central radio (102-d) is configured to receive a message from a server (104). The server (104) may be an HMI based server application.
[00133] In one aspect, a format of the message is shown in figure 9B. Referring to figure 9B, a message format at the destination central radio is shown, according to an embodiment of the present invention. The message comprises a start of packet (SOP), a packet originating radio ID, a packet destination radio ID, a length of actual message (LOP), actual message and an end of the packet (EOP).
[00134] At step (704), the destination central radio (102-d) is configured to transmit the message to the destination terminal radio (106-d). The message may be divided into a second set of frames. Further, the destination central radio (102-d) transmits each frame from the second set of frames.
[00135] At step (706), the destination terminal radio (106-d) is configured to receive frames from the destination central radio (102-d). Once the destination terminal radio (106-d) receives the start of packet, the destination terminal radio (106-d) will start storing a frame byte and a frame sequence number in two different multidimensional arrays.
[00136] In one aspect, a size of one-dimensional array buffer to store the frame sequence number will be given as per equation 4.
a size of one-dimensional array buffer to store the frame sequence number = [1] [Maximum no. of frames] … equation 4
[00137] Further, a size of one-dimensional array buffer to store the frame bytes will be given as per equation 5.
a size of one-dimensional array buffer to store the packet frame bytes = [1] [Maximum packet length] … equation 5
[00138] At step (712), the destination terminal radio (106-d) is configured to check if the EOP is received. If the EOP is not received, the destination terminal radio (106-d) stores the frames received from the destination central radio (102-d) at step (714).
[00139] Once the EOP is received, the destination terminal radio (106-d) checks for missing sequence number in the frame sequence number array at step (716). The missing sequence number indicates that one or more frames are missing from the second set of frames.
[00140] At step (718), if the missing sequence number is identified, then the destination terminal radio (106-d) is configured to transmit a request for retransmission to the destination central radio (102-d).
[00141] At step (710), the destination terminal radio (106-d) checks if the number of retransmissions is less than 3 or not. If the number of retransmissions is less than 3, then the request for retransmission is transmitted by the destination terminal radio (106-d) to the destination central radio (102-d).
[00142] Once the request for retransmission is received, the destination central radio (102-d) is configured to transmit the one or more frames missing from the second set of frames to the destination terminal radio (106-d).
[00143] If destination terminal radio (106-d) is not able to receive all frames even after 3 retransmission requests, then destination terminal radio (106-d) transmits a negative acknowledgement (NACK) signal to the destination central radio (102-d) at step (720).
[00144] At step (722), the destination terminal radio (106-d) transmits an acknowledgement (ACK) signal to the destination central radio (102-d), when no frame is missing. The acknowledgment signal indicates that the destination terminal radio (106-d) received full message from the destination central radio (102-d). The message is further displayed to a user using a destination Human based Machine Interface (HMI) device. The destination HMI is associated with the destination terminal radio (106-d).
[00145] At step (724), the destination terminal radio (106-d) clears a buffer on transmitting one of the acknowledgement (ACK) signal or the negative acknowledgement (NACK) signal.
[00146] At step (708), upon receiving the start of packet if the destination terminal radio (106-d) fails to receive any frames for a time interval and the EOP is not received, then the destination terminal radio (106-d) forcefully assumes the EOP. Further, the destination terminal radio (106-d) considers that the one or more frames are missing from the second set of frames and starts the processing of the one or more frames. The time interval may be 10 consecutive intervals.
[00147] Referring now to figure 8, a flowchart depicting a method for a centralized messaging service is shown, according to an embodiment of the present invention.
[00148] At a step (802), receiving a first set of frames associated with a message from a source terminal radio (106-s). In one embodiment, a source central radio (102-s) is configured to receive the first set of frames from the source terminal radio (106-s).
[00149] In one embodiment, the source terminal radio (106-s) receives a message request from the source central radio (102-s). The source terminal radio (106-s) further composes the message using a source Human based machine interface (HMI) device. The source terminal radio (106-s) transmits the first set of frames to the source central radio (106-s). The first set of frames are based on N bytes of the message associated with an air transmit burst.
[00150] At step (804), transmitting one of: an acknowledgement signal to the source terminal radio upon receiving the first set of frames; or a request for retransmission of one or more frames upon identifying missing of the one or more frames from the first set of frames. In one embodiment, the source central radio (102-s) is configured to transmit one of the acknowledgement signal to the source terminal radio upon receiving the first set of frames; or the request for retransmission of one or more frames upon identifying missing of the one or more frames from the first set of frames.
[00151] At step (806), generating the message upon receiving the first set of frames. In one embodiment, the source central radio (102-s) is configured to generate the message upon receiving the first set of frames.
[00152] At step (808), transmitting the message to a server (104), wherein the server (104) comprising: identifying a destination central radio (102-d) and a destination terminal radio (106-d) associated with the message. In one embodiment, the source central radio (102-s) is configured to transmit the message to the server (104). The server (104) is further configured to identify the destination central radio (102-d) and the destination terminal radio (106-d).
[00153] At step (810), wherein the destination central radio (102-d) comprising: receiving the message from the server (104); dividing the message into a second set of frames based on N bytes of message; and transmitting the second set of frames associated with the message to the destination terminal radio (106-d). In one embodiment, the destination central radio (102-d) is configured to receive the message from the server (104). Upon receiving the message, the destination central radio (102-d) divides the message into the second set of frames based on N bytes of message. The destination central radio (102-d) transmits the second set of frames associated with the message to the destination terminal radio (106-d).

[00154] However, any number of steps of the above flowcharts may be implemented as a loop. Further, the steps of the above flowcharts may be implemented in any order.
[00155] It is also possible to implement the method for a centralized messaging service of the present invention by executing the above flowchart while skipping one or more steps or while implementing one or more steps multiple times.
[00156] Therefore, the system and the method for a centralized messaging service is not limited by the order of the steps in the flowchart.
[00157] In an advantageous embodiment, the system and method for centralized based grouped communications for transmitting a message with a low probability of detection. In order to ensure the less probability of detection, the message is transmitted over an air in the forms burst of a low duration in randomized time slots. The system and method are configured to implement a randomized beacon transmission algorithm at a central radio. The optimized burst duration and the randomized algorithm for burst transmissions makes it less susceptible to get detected.
[00158] The system and method implement a retransmission algorithm and a handshaking algorithm at a terminal radio and the central radio to ensure guaranteed message delivery between two terminals and its processing. The system and method are configured to transfer an error free packet from one terminal to another terminal.
[00159] 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.
[00160] 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(s) to furthering the art and are to be construed as being without limitation to such specifically recited examples and conditions.
[00161] Moreover, all statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass equivalents thereof.