A WIRELESS PACKET TRANSMISSION NODE
Field of the Disclosure
The present disclosure relates to communication networks, and more particularly, to a wireless packet transmission node transporting time sensitive packets without introducing wander.
Glossary
Wireless Packet Transmission Node - any packet switching network node with at least one
wireless interface and zero or more wired interfaces forming a transmission network,
Radio Junction (RJ) - a wireless packet transmission node located between other wireless
packet transmission nodes and connecting one node to other nodes providing multi-tier and multi-hop transmission network.
End Point (EP) - a wireless packet transmission node that is located at the periphery of the transmission network and connects end user node to a Radio Junction (RJ). EP consists of one radio interface and several wired interfaces.
Wireless Packet Backhaul Network (WPBN) - a network consisting of several wireless packet
transmission nodes along with a designated root node from where the transmission tree begins. The network also provides several hops and several tiers. The EP or root node provides connectivity to end user nodes.
Packets: - a relatively small sequence of digital symbols (e.g., several tens of binary octets up to several thousands of binary octets) that contains a payload and one or more headers. The payload is the information which the source wishes to send to the destination. The headers contain information about the nature of the payload and its delivery. Packets can be consumed by intermediate node or can be relayed to next node.
Time Sensitive Packets: - packets which carry timing information for synchronizing the network
nodes or end user nodes.
Frames: - packets at the link layer of a communication system. These packets are consumed by the receiving node and not forwarded/relayed to another node the chain.
Synchronization Master: - a designated node in the WPBN which generates the radio clock.
Synchronization Slave: - these nodes receive control frames and synchronize themselves with
the master.
Radio Clock: controls transmission and reception on radio interface(s) of WPTNs making a WPBN.
Point-to-point Network (P2P) - a communication network that provides a communication link
from one source node to a destination node.
Point-to-Multi-point Network (P2MP) - a communication network that provides a
communication link from one source node to multiple destination nodes.
Background
A typical cellular communication system comprises Mobile Stations (MS), Base Station Subsystems and a Network Switching Subsystem (NSS). Each Base Station Subsystem is essentially a Base Station Controller (BSC) coupled to multiple Base Transceiver Stations (BTSs), located at some distance from the BSC. The BSC and its associated BTSs are linked together by means of a 'backhaul' network which may be a wired or wireless network, depending on the deployment requirements. The base stations and their controllers are known with different terminologies for varying networks definitions based on various radio technologies. However, in all types of wireless communication networks, the base stations as the wireless access node at remote places are connected to their network controller node through a backhaul network.
The packet based wired and wireless networks are becoming popular choice for backhaul due to lesser cost. However, network synchronization requirements of the BTS remain a concern thereof.
Further, the legacy systems based on TDM interfaces need to be supported by the packet transmission networks. TDMoP is one technology which uses the packet based transmission network and supports legacy TDM systems to carry traffic and network synchronization information. The synchronization requirements are driven by the recognized standards. Moreover, the TDMoP gateways are used to provide CES (circuit emulation service) for TDM traffic and network synchronization over packet networks.
Figure 1 illustrates a TDMoP (Time Division Multiplexing over Packets) network as known in the art. As per the figure, the TDM Gateway 101 converts the TDM contents into packets and routes the connected Wireless Packet Transmission Nodes (WPTN) of the Wireless Packet Backhaul Network (WPBN). The Packet Node processes packets with payload and routes them towards the destination Gateway 102 connected with the destination Packet Node through intermediate packet transmission node/s. It supports both way communications. The
processing at the Packet Nodes is required to meet digital transmission characteristics to ensure smooth clock recovery at the designation TDM gateway for smooth communication.
However, the clock recovery in general is not smooth that easy because of the variations in clock rate over time. These variations in clock rate over time causes the problem of Wander. Wander arises due to slow; smooth drifting of clock rate due to temperature changes, aging and slaving inaccuracies, as well as due to variations in processing time for time sensitive critical functions in software intensive systems. Packet Switching nodes are typically optimized for higher traffic handling without any consideration of time relationship of corresponding packets, causing another challenge for adaptive clock recovery methods for clocks distribution required for Constant Bit Rate (CBR) services. Specification of wander becomes more complex in case of differing time intervals. Moreover, each time sensitive packet is subjected to different transport characteristics. This leads to non-uniform arrival time of each packet. Ideally, the destination Gateway should receive a packet at every scheduled time interval. Since the intermediate packet system introduces systematic and random delays, the arrival is not exactly at the scheduled time. If the packet arrives before scheduled time, it creates positive time interval error (TIE). If the packet arrives after the scheduled time, it creates negative time interval error. There is another delay which plays an important role in clock extraction and is known an inter packet delay. It occurs due to the difference between the arrival time of the current packet and the arrival time of the previous packet.
Moreover, impairments like Random delay variation, Low frequency delay variations, systematic delay variations, routing changes and congestion effects etc are introduced by Packet Switched Networks and are described in ITU-T specification G.8261. The Adaptive clock recovery (ACR) methods required to tolerate these packet network impairments and provide recovered clock satisfactorily. However, the combination of undefined wander characteristics due to inherent system design of wireless packet switching nodes with defined impairments like systematic delays remains challenge for ACR algorithms in the present art.
US Patent 7,243,150 provides a mechanism to reduce the timing variation in a synchronized network. Each node in the network will know its transmission time and will process the input packets such that the processing is finished just before transmission time. This will avoid any queuing. Overall, this mechanism will result in reduced latency according to the invention. However, the cited document considers highly deterministic systems where processing of data will always finish before transmission opportunity. Building such deterministic characteristics into a system increases complexity and cost. The computing resources are wasted during waiting time and the mechanism will result in a queue building at the input since there is no control over the input. The cited document further does not have mechanism to avoid output wander in data packets.
Similarly, other timing techniques over packet distribution methods involve IEEE 1588, Circuit Emulation services, where the service and the timing information are carried together.
Summary
Embodiments of the present disclosure relate to the packet processing at WPTN and a Wireless Packet Backhaul Network (WPBN) thereof, to make it suitable for its usage to carry traffic of time sensitive packets without introducing wander. An embodiment of the present disclosure illustrates a Wireless Packet Transmission Node (WPTN) (200) comprising a packet processor (201) configured to receive, process and transmit time-sensitive packets without introducing wander on the basis of precise and accurate processing clock and a first set of control signals (203); a packet control unit (202) configured to generate said precise and accurate clock and said first set of control signals (203) on the basis of a low accuracy clock signal (204); said packet processor (201) being further configured to extract a synchronization clock signal (205) from received time sensitive packets when the WPTN is an intermediate node of a network; and said packet control unit (202)) being further configured to generate said first set of control signals (203) in conformity to said extracted synchronization clock signal (205) when the WPTN is an intermediate node of a network.
Yet another embodiment of the present disclosure illustrates a communication network comprising a Wireless Packet Transmission Node (WPTN) (200) comprising a packet processor (201) configured to receive, process and transmit time-sensitive packets without introducing wander on the basis of precise and accurate processing clock and a first set of control signals (203); a packet control unit (202) configured to generate said precise and accurate clock and said first set of control signals (203) on the basis of a low accuracy clock signal (204); said packet processor (201) being further configured to extract a synchronization clock signal (205) from received time sensitive packets when the WPTN is an intermediate node of a network; and said packet control unit (202)) being further configured to generate said first set of control signals (203) in conformity to said extracted synchronization clock signal (205) when the WPTN is an intermediate node of a network.
An embodiment of the present disclosure illustrates a multi-tier communication network comprising a Wireless Packet Transmission Node (WPTN) (200) comprising a packet processor (201) configured to receive, process and transmit time-sensitive packets without introducing wander on the basis of precise and accurate processing clock and a first set of control signals (203); a packet control unit (202) configured to generate said precise and accurate clock and said first set of control signals (203) on the basis of a low accuracy clock signal (204); said packet processor (201) being further configured to extract a synchronization clock signal (205) from received time sensitive packets when the WPTN is an intermediate node of a network; and said packet control unit (202)) being further configured to generate said first set of control signals (203) in conformity to said extracted synchronization clock signal (205) when the WPTN is an intermediate node of a network.
Another embodiment of the present disclosure illustrates a method of operating a wireless packet transmission node (WPTN) comprising: receiving, processing and transmitting time sensitive packets without introducing wander on the basis of precise and accurate processing clock and a first set of control signals (203); and generating said precise and accurate clock and
said first set of control signals (203) on the basis of a low accuracy clock signal (204); said processing further extracts a synchronization clock signal (205) from received time sensitive packets when the WPTN is an intermediate node of a network; and said generating further generates said first set of control signals (203) in conformity to said extracted synchronization clock signal (205) when the WPTN is an intermediate node of a network.
Brief Description of Drawings: -
The aforementioned aspects and other features of the present disclosure will be explained in the following description, taken in conjunction with the accompanying drawings, wherein
Figure 1 illustrates a diagrammatic representation of a TDMoP (Time Division
Multiplexing over Packets) network as known in the art.
Figure 2 illustrates a block diagram of a wireless packet transmission node as per the
present disclosure.
Figure 3 illustrates a detailed block diagram representation of the packet control unit
according to the present disclosure
Figure 4 illustrates a multi-tier communication network with minimal wander according
to an embodiment of the present disclosure.
Figure 5 illustrates the functional block diagram of a Radio Junction (RJ) node according
to an embodiment of the present disclosure.
Figure 6 illustrates the functional block diagram of an End Point (EP) network node
according to an embodiment of the present disclosure.
Figure 7 illustrates medium access by synchronized master and synchronized slave in a
deterministic wireless packet transmission network in a point to point link.
Figure 8 illustrates medium access by synchronized master and multiple synchronized
slaves in a deterministic wireless packet transmission network in a point to multi-point link.
Figure 9 illustrates a comparison between Time Interval Error (TIE) graph according to an
embodiment of the present disclosure and according to conventional art.
Figure 10 illustrates a comparison between the Fourier transform of output of the TIE graph according to an embodiment of the present disclosure and according to conventional art.
Figure 11 illustrates a method of operating a wireless packet transmission node (WPTN) according to an embodiment of the present disclosure
Detailed Description
Exemplary embodiments now will be described with reference to the accompanying drawings. The disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey its scope to those skilled in the art. The terminology used in the detailed description of the particular exemplary embodiments illustrated in the accompanying drawings is not intended to be limiting. In the drawings, like numbers refer to like elements.
The specification may refer to "an", "one" or "some" embodiment(s) in several locations. This does not necessarily imply that each such reference is to the same embodiment(s), or that the
feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments.
As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless expressly stated otherwise. It will be further understood that the terms "includes", "comprises", "including" and/or "comprising" when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may be present. Furthermore, "connected" or "coupled" as used herein may include wirelessly connected or coupled. As used herein, the term "and/or" includes any and all combinations and arrangements of one or more of the associated listed items.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
"Wireless communication system" includes any communication system or any combination of different communication systems. The communication system may be a fixed communication system or a wireless communication system or a communication system utilizing both fixed networks and wireless networks. The protocols used the specifications of communication systems, servers and user terminals, especially in wireless communication, develop rapidly. Such development may require extra changes to an embodiment. Therefore, all words and
expressions should be interpreted broadly and they are intended to illustrate, not to restrict the embodiment.
It should be understood that embodiments of the present disclosure may be included in various types of wireless communication networks intended to be within the scope of the present disclosure, although not limited to, a GSM network, a CDMA network, TDMA, FDMA, OFDMA, SC-FDMA, a worldwide interoperability for microwave access (WiMAX) network, a WCDMA network, a time division synchronous code division multiple access (TD-SCDMA) network, a CDMA2000 network, a personal handy phone system (PHS) network, a cluster network, a long term evolution (LTE) network, and an air interface evolution (AIE) network. The terms "network" and "systems" are often used interchangeably.
The figures depict a simplified structure only showing some elements and functional entities, all being logical units whose implementation may differ from what is shown. The connections shown are logical connections; the actual physical connections may be different. It is apparent to a person skilled in the art that the structure may also comprise other functions and structures. It should be appreciated that the functions, structures, elements and the protocols used in communication are irrelevant to the present disclosure. Therefore, they need not be discussed in more detail here.
Also, all logical units described and depicted in the figures include the software and/or hardware components required for the unit to function. Further, each unit may comprise within itself one or more components, which are implicitly understood. These components may be operatively coupled to each other and be configured to communicate with each other to perform the function of the said unit.
The present method and apparatus provide an alternative method of exploiting packet networks for telephony service that is evolutionary rather than revolutionary. This method uses packet networks as a drop in replacement for native TDM networks. It seamlessly interfaces to
all existing equipment, such as legacy PBXs and switches, and inherently provides all the hundreds of telephony features and the PSTN quality to which customers have become accustomed.
A wireless packet backhaul (hereinafter referred as "transmission") network may include a number of wireless packet transmissions Node and other network entities. For simplicity, only one Node 200 is shown in FIG. 2. A Node is a connection point (root node), either a redistribution point (an intermediate node) or a communication endpoint (some terminal equipment). The root node interfaces with multiple users and generates radio synchronization clock for complete network. The intermediate node provide transit path between two hops of a tier. The End points (EP) are the leaf level nodes. These nodes provide connectivity to the end user nodes. EP consists of one radio interface and several wired interface. The complete network is synchronized and provides deterministic access on radio interface to each media sharing node. To improve system capacity, the overall coverage area of a Node may be partitioned into multiple (e.g., three) smaller areas. Each smaller area may be served by a respective Node subsystem.
FIG. 2 illustrates a block diagram of a wireless packet transmission node as per the present disclosure. The wireless packet transmission node 200 comprises a packet processor 201 operatively coupled to a packet control unit 202. The packet processor unit 201 is configured to receive time sensitive traffic data packets and transmit time-sensitive traffic data packets without introducing wander on the basis of precise and accurate processing clock and a first set of control signals 203. Further, the packet processor unit is configured to extract a synchronization clock signal 205 from received time sensitive packets when the WPTN is an intermediate node or a radio junction of a network.
Further, the packet control unit 201 is configured to generate said precise and accurate clock and said first set of control signals 203 on the basis of a low accuracy clock signal 204. The packet control unit 202 being further configured to generate said first set of control signals 203
in conformity to said extracted synchronization clock signal 205 when the WPTN is an intermediate node of a network.
Furthermore, packet processor 201 receives configurations data inputs along with said precise and accurate clock and said first set of control signals 203 to generate processed output without introducing wander on wired and/or wireless interfaces. The configuration data inputs fed to the packet processor includes format conversion configuration data and prioritization configurations data. The time-sensitive packets fed to the Packet Processor 201 may be from wired and/or wireless interfaces. These received packets are user traffic (general IP traffic), TDM traffic (as TDMoP), and link control packets. The Link Control frames further includes radio clock frames for synchronization from available synchronization master node.
Moreover, discovery frames from synchronization master node contains attributes of the link, link management frames from synchronization master and synchronization slave node for access, authentication and link establishment and release.
According to an exemplary embodiment, if the wireless packet transmission node is configured as Root Node, the packet processor does not receive link control frames containing radio clock information. Packet processing functions on receiving link control frames are as follows: for Radio Clock input frames, processing function is to extract the clock synchronization input 205 to be given to packet control unit 201; for discovery input frames, processing function is to Identify the available master and information related to its transmission controls; and Link Management input frames, processing function is to perform all link management functions as Access request and grant, authentication request, Link Establishment /Release Request.
Packet processing treats different type of inputs packets differently and applies suitable priority in processing. Time-sensitive packets such as TDMoP, Radio Clock frames etc. are processed with high priority and the instruction required for their critical flows are executed from Cache.
This implementation of Packet processing unit is based on highly accurate and increased granularity of said precise and accurate clock and said first set of control signals 203 makes it an absolute deterministic from the task completion perspective. The time sensitive packet output so generated by the packet processer 201 is ensured to be wander free.
According to another exemplary embodiment of the Packet Processor on initialization, if WPTN is configured as synchronization slave Node, is instructed to enable radio interface and listen to control frame from synchronization master. On receiving the valid clock frame, the timing interval information is generated as synchronization clock input signal 205 to be used by Packet Control Unit 202 for further control and synchronization purpose.
Figure 3 illustrates a detailed block diagram representation of the packet control unit according to the present disclosure. The packet control unit 202 comprises and a selection and input processing unit 301, a radio clock generator 302 and a control cache 303. All three (301, 302 and 303) are operatively coupled with each other. The selection and input processing unit 301 is configured to generate said second set of control signals 304 based on feedback signal 305 providing drift data of said clock synchronization signal pertaining to said precise and accurate processing clock and a first set of control signals 203. The radio clock generator 302 configured to generate said precise and accurate clock and a first set of control signals 203 using cache-based processing, and said signal providing radio clock drift data 305 pertaining to said precise and accurate processing clock 203 on the basis of said second set of control signals 304. The control cache 303 configured to provide said cache-based processing, operating at the high priority.
According to another exemplary embodiment, the radio clock generator 302 configured to generate said precise, accurate and wander free clock and first set of control signals 203 using cache-based processing, and operating at the high priority said signal providing radio clock drift data 305 pertaining to said precise and accurate processing clock 203 on the basis of said second set of control signals 304.
Further, the packet control unit 202 takes configuration input from user. The configuration inputs include TDM Clock configuration data, Radio Clock Configuration data and Radio Link Configuration data.
According to another embodiment, the packet control unit 202 also takes clock synchronization input 205 from the packet processor unit 201 is extracted from data received from higher node in the packet network hierarchy. This input is not available at the root node (first WPTN) of Wireless Packet Backhaul Network.
The packet control unit 202 processes input and generated control input for the radio clock generation unit. This unit checks the drift data of said clock synchronization signal for long term integration and adjusts the control output 304 to the radio clock generator 302.
Further, the radio clock generator 302 is coupled to the input processing unit 301 and control cache 303 and the low accuracy clock source 204. The radio clock generator 302 executes instructions from cache at high priority. 302 ensure that the generation of the wander free said precise and accurate clock and said control signals 203 to said Packet Processor 201 leading to generate a wander free output.
Furthermore, the precise and accurate clock and said first set of control signals 203 as generated from radio clock generator 302 includes Radio Clock, TX/RX control for Wireless Interface, TX/RX control for wired interface, and processing control based on given configuration data. It also generates drift data of said clock synchronization signal Selection and Input Processing Unit 301 as feedback signal. The selection and input processing unit uses said feedback signal 305 to determine drifts and does perform long term integration on the drift data to compensate wander.
Figure 4 illustrates a multi-tier communication network with minimal wander according to an embodiment of the present disclosure. The wireless packet backhaul communication network (WPBN) comprises multiple (0 or more) long range tier comprising multiple Wireless Packets Transmission nodes (WPTN). The Wireless Packets Transmission node configured to provide long distance radio links and multiple (0 or more) short range tier comprising multiple WPTN configured to provide short distance radio links.
WPTN arranged in long distance radio links are referred to as Radio Junctions (RJ) 401, 402 and the WPTN arranged in short distance radio links are referred to as End Points (EP) 401a, 401b, 401c, 401d, 401e, 402a, 402b, 402c, 402d, 402e. According to the present arrangement, RJ 401 is coupled to the user gateway through wired or wireless link and RJ 402 through wireless link. RJ 402 is coupled to RJ 401 and possible next hope WPTN over a long distance point-to-point (p2p) or point-to-multipoint (p2mp) radio links. Such long distance radio link coupling between RJ 401 and RJ 402 may be referred to as Tier 1.
Further, multiple EPs are coupled to RJ 401 and 402 through short distance p2p or p2mp radio links. According to the present embodiment, EPs 401a, 401b, 401c, 401d, 401e are coupled to RJ 401 through short distance radio links and EPs 402a, 402b, 402c, 402d, 402e are coupled to RJ 402 through short distance radio links. Such short distance radio link coupling between RJ and EP may be referred to as Tier 2.
However, the present disclosure is not limited to the present embodiments. The present disclosure can be modified in various forms. Thus, the embodiments of the present disclosure are only provided to explain more clearly the present disclosure to the ordinarily skilled in the art of the present disclosure. In other embodiments, EP can be replaced with another RJ to provide yet another tier Tier-3. Similarly, the tier levels can be expanded according to the network requirement.
Figure 5 illustrates the functional block diagram of a Radio Junction (RJ) node according to an embodiment of the present disclosure. An RJ node comprises a WPTN (200) as illustrated in previous embodiments. The RJ acting as WPTN may be equipped with multiple wireless interfaces for radio links with Tier 1 (0 or more) and Tier 2 (0 or more). The RJ acting as WPTN may also be equipped with wired interfaces to serve service users such as time sensitive packet Gateway. RJ does necessary conversion between multiple Tier wireless interface and the also between wireless and wired interface. Further, the root node is synchronization master for Tier-1 and RJ are synchronization masters for Tier-2.
Figure 6 illustrates the functional block diagram of an End Point (EP) network node according to an embodiment of the present disclosure. An EP network node is a reduced capability RJ (601) as described earlier. EP has single wireless interface. EP does not support wireless transit (multi-hope) function and also does not support multiple wireless Tiers. It has the same wired interface/s as RJ and does necessary format conversions.
In p2p and/or p2mp radio links, a WPTN is configured to operate as a transmission synchronization master network node where the node is configured to indicate its presence to the secondary transmission synchronization slave nodes, to detect upcoming slave network nodes, to authenticate the slave network nodes, and to allocate the communication resources. These communication resources are monitored continuously and may be reconfigured to ensure high link level availability. The transmission master network node may additionally be configured to allocate transmission opportunity to the transmission slave network nodes. In case of p2p radio links, the total transmission time may equally be divided between the transmission master network node and the transmission slave network nodes as shown in Figure 7.
In case of p2mp radio links, the total transmission time is dynamically divided between the downlink and uplink communication depending upon the no of slave nodes sharing the common channel as shown in Figure 8.
The total transmission time is the total time available for transmission, which is calculated by taking into account various parameters such as number of transmitters in the communication network sharing a common medium, the available spectrum, the encoding scheme used the network nodes and the maximum spatial distance. The total transmission time may vary with the changing throughput requirements of the communication network.
According to another embodiment, the transmission synchronization master network node may transmit discovery frames at the time of initialization. The discovery frames may contain information such as the number of transmission slave network nodes being supported by the transmission master network node and parameters necessary to setup higher protocol layers with the transmission master network nodes. The discovery frames assist a transmission slave network node to select the most appropriate transmission master network node and set up lower layer connectivity.
According to yet another embodiment of the present disclosure, a WPTN node is configured to locate the position of an upcoming network node (EP or RJ) in a communication network by way of sector information. The upcoming network node is configured to detect the sector information and report the same to the centralized server of the communication network. The central server then identifies the location of the upcoming network node according to the reported sector information.
Figure 9 illustrates a comparison between the TIE (Time Interval Error) graph according to an embodiment of the present disclosure and the conventional art. As described previously in the disclosure, TIE refers to error in scheduled arrival time of a data packet and the actual arrival time. For example, at TDM GW at ingress samples TDM contents every 2ms and packetizes it. The data packets are then sent to the destination TDM GW. Ideally, TDM GW should receive a data packet every 2ms, however, introduction of random and systematic delays of Wireless Packet Backhaul Network (WPBN) results in actual arrival time greater or lesser than the ideal
arrival time of 2ms. The graph 9(b) represents TIE against time, representing systematic TIE variations without wander.
Figure 10 illustrates a comparison between the Fourier transform of the TIE graph according to an embodiment of the present disclosure and according to the conventional art respectively.
Further, the graph 10(a) represents various frequencies component in TIE characteristic of received data. The significant low frequency components (less than 20 Hz) present in the received data make TDM GW clock extraction mechanism to fail. Therefore graph 9(a) and 10(a) represent the problem prevailing in the present art. The graph 9(b), however represent TIE curve with the applied invention. The graph represents that the frequent and systematic TIE variations are significantly reduced. Graph 10 (b) representing frequency components of TIE clearly confirm the absence of low frequency component ie wander.
Figure 11 illustrates a method of operating a wireless packet transmission node (WPTN) according to an embodiment of the present disclosure. The method comprises in step 1101 receiving, processing and transmitting time sensitive packets without introducing wander; in step 1102 generating said precise and accurate clock and said first set of control signals (203) on the basis of a low accuracy clock signal (204); said processing further extracts a synchronization clock signal (205) from received time sensitive packets when the WPTN is an intermediate node of a network; and said generating further generates said first set of control signals (203) in conformity to said extracted synchronization clock signal (205) when the WPTN is an intermediate node of a network.
Embodiments of the present disclosure deliver deterministic, contention free access, low latency, point to point links, point to multi point links, multi tier cluster, multi hop backhaul cluster and suitable transmission of TDM traffic and time sensitive packets without introducing wander.
Those of skill in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.
Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the disclosure herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.
The various illustrative logical blocks, modules, and circuits described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.
The steps of a method or algorithm described in connection with the disclosure herein may be
embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC or FPGA. The ASIC or FPGA may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.
In one or more exemplary designs, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers.
Combinations of the above should also be included within the scope of computer-readable media.
The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein but are to be accorded the widest scope consistent with the principles and novel features disclosed herein.

We claim:
1. A Wireless Packet Transmission Node (WPTN) (200) comprising:
a packet processor (201) configured to receive, process and transmit time-sensitive packets without introducing wander on the basis of precise and accurate processing clock and a first set of control signals (203);
a packet control unit (202) configured to generate said precise and accurate clock and said first set of control signals (203) on the basis of a low accuracy clock signal (204);
said packet processor (201) being further configured to extract a synchronization clock signal (205) from received time sensitive packets when the WPTN is an intermediate node of a network; and
said packet control unit (202)) being further configured to generate said first set of control signals (203) in conformity to said extracted synchronization clock signal (205) when the WPTN is an intermediate node of a network.
2. The Wireless Packet Transmission Node (200) as claimed in claim 1, wherein said packet
control unit (202) comprises :
a selection and input processing unit (301) configured to generate said second set of control signals (304) based a feedback signal (305) providing drift data of said clock synchronization signal pertaining to said precise and accurate processing clock and a first set of control signals (203);
a radio clock generator (302) configured to generate said precise and accurate clock and first set of control signals (203) using cache-based processing, and/or

operating at the high priority and said signal providing radio clock drift data (305) pertaining to said precise and accurate processing clock (203) on the basis of said second set of control signals (304); and
a control cache (303) configured to provide said cache-based processing, operating at the high priority.
3. The Wireless Packet Transmission Node as claimed in claim 1, wherein said precise and
accurate clock and a first set of control signals (203) comprises:
a radio clock;
a transceiver control for wireless interface;
a transceiver control for wired interface; and
a processing control based on given configuration.
4. A communication network comprising a Wireless Packet Transmission Node (WPTN)
(200) comprising:
a packet processor (201) configured to receive, process and transmit time-sensitive packets without introducing wander on the basis of precise and accurate processing clock and a first set of control signals (203);
a packet control unit (202) configured to generate said precise and accurate clock and said first set of control signals (203) on the basis of a low accuracy clock signal (204);

said packet processor (201) being further configured to extract a synchronization clock signal (205) from received time sensitive packets when the WPTN is an intermediate node of a network; and
said packet control unit (202)) being further configured to generate said first set of control signals (203) in conformity to said extracted synchronization clock signal (205) when the WPTN is an intermediate node of a network.
5. The communication network as claimed in claim 4, wherein said packet control unit
(202) comprises :
a selection and input processing unit (301) configured to generate said second set of control signals (304) based a feedback signal (305) providing drift data of said clock synchronization signal pertaining to said precise and accurate processing clock and a first set of control signals (203);
a radio clock generator (302) configured to generate said precise and accurate clock and first set of control signals (203) using cache-based processing, and/or operating at the highest priority and said signal providing radio clock drift data (305) pertaining to said precise and accurate processing clock (203) on the basis of said second set of control signals (304); and
a control cache (303) configured to provide said cache-based processing, operating at the highest priority.
6. The communication network as claimed in claim 6, wherein said precise and accurate
processing clock and a first set of control signals (203) comprises:
a radio clock;

a transceiver control for wireless interface;
a transceiver control for wired interface; and
a processing control based on given configuration.
7. A multi-tier communication network comprising a Wireless Packet Transmission Node
(WPTN) (200) comprising:
a packet processor (201) configured to receive, process and transmit time-sensitive packets without introducing wander on the basis of precise and accurate processing clock and a first set of control signals (203);
a packet control unit (202) configured to generate said precise and accurate clock and said first set of control signals (203) on the basis of a low accuracy clock signal (204);
said packet processor (201) being further configured to extract a synchronization clock signal (205) from received time sensitive packets when the WPTN is an intermediate node of a network; and
said packet control unit (202)) being further configured to generate said first set of control signals (203) in conformity to said extracted synchronization clock signal (205) when the WPTN is an intermediate node of a network.
8. The multi-tier communication network as claimed in claim 7, wherein said packet
control unit (202) comprises :
a selection and input processing unit (301) configured to generate a second set of control signals (304) based on said second configuration data (206), and a

feedback signal (305) providing radio clock drift data pertaining to said precise and accurate processing clock and a first set of control signals (203);
a radio clock generator (302) configured to generate said precise and accurate clock and first set of control signals (203) using cache-based processing, operating at the highest priority and said signal providing radio clock drift data (305) pertaining to said precise and accurate processing clock (203) on the basis of said second set of control signals (304); and
a control cache (303) configured to provide said cache-based processing, operating at the highest priority.
9. The multi-tier communication network as claimed in claim 7, wherein said precise and
accurate processing clock and a first set of control signals (203) comprises:
a radio clock;
a transceiver control for wireless interface;
a transceiver control for wired interface; and
a processing control based on given configuration.
10. A Radio Junction comprising a Wireless Packet Transmission Node (WPTN) (200)
comprising:
a packet processor (201) configured to receive, process and transmit time-sensitive packets without introducing wander on the basis of precise and accurate processing clock and a first set of control signals (203);

a packet control unit (202) configured to generate said precise and accurate clock and said first set of control signals (203) on the basis of a low accuracy clock signal (204);
said packet processor (201) being further configured to extract a synchronization clock signal (205) from received time sensitive packets when the WPTN is an intermediate node of a network; and
said packet control unit (202)) being further configured to generate said first set of control signals (203) in conformity to said extracted synchronization clock signal (205) when the WPTN is an intermediate node of a network.
11. The Radio Junction as claimed in claim 10, wherein said packet control unit (202) comprises:
a selection and input processing unit (301) configured to generate a second set of control signals (304) based on said second configuration data (206), and a feedback signal (305) providing radio clock drift data pertaining to said precise and accurate processing clock and a first set of control signals (203);
a radio clock generator (302) configured to generate said precise and accurate clock and first set of control signals (203) using cache-based processing, operating at the highest priority and said signal providing radio clock drift data (305) pertaining to said precise and accurate processing clock (203) on the basis of said second set of control signals (304); and
a control cache (303) configured to provide said cache-based processing, operating at the highest priority.

12. The Radio Junction as claimed in claim 10, wherein said precise and accurate processing
clock and a first set of control signals (203) comprises:
a radio clock;
a transceiver control for wireless interface;
a transceiver control for wired interface; and
a processing control based on given configuration.
13. A End Point comprising a Wireless Packet Transmission Node (WPTN) (200) comprising:
a packet processor (201) configured to receive, process and transmit time-sensitive packets without introducing wander on the basis of precise and accurate processing clock and a first set of control signals (203);
a packet control unit (202) configured to generate said precise and accurate clock and said first set of control signals (203) on the basis of a low accuracy clock signal (204);
said packet processor (201) being further configured to extract a synchronization clock signal (205) from received time sensitive packets when the WPTN is an intermediate node of a network; and
said packet control unit (202)) being further configured to generate said first set of control signals (203) in conformity to said extracted synchronization clock signal (205) when the WPTN is an intermediate node of a network.
14. The End Point as claimed in claim 13, wherein said packet control unit (202) comprises :

a selection and input processing unit (301) configured to generate a second set of control signals (304) based on said second configuration data (206), and a feedback signal (305) providing radio clock drift data pertaining to said precise and accurate processing clock and a first set of control signals (203);
a radio clock generator (302) configured to generate said precise and accurate clock and first set of control signals (203) using cache-based processing, operating at the highest priority and said signal providing radio clock drift data (305) pertaining to said precise and accurate processing clock (203) on the basis of said second set of control signals (304); and
a control cache (303) configured to provide said cache-based processing, operating at the highest priority.
15. The End Point as claimed in claim 13, wherein said precise and accurate processing clock
and a first set of control signals (203)comprises:
a radio clock;
a transceiver control for wireless interface;
a transceiver control for wired interface; and
a processing control based on given configuration.
16. A method of operating a wireless packet transmission node (WPTN) comprising:
receiving, processing and transmitting time sensitive packets without introducing wander on the basis of precise, accurate and wander free processing clock and a first set of control signals (203);

generating said precise and accurate clock and said first set of control signals (203) on the basis of a low accuracy clock signal (204);
said processing further extracts a synchronization clock signal (205) from received time sensitive packets when the WPTN is an intermediate node of a network; and
said generating further generates said first set of control signals (203) in conformity to said extracted synchronization clock signal (205) when the WPTN is an intermediate node of a network.
17. The method as claimed in claim 16, wherein said said precise and accurate processing clock and a first set of control signals (203) comprises:
a radio clock;
a transceiver control for wireless interface;
a transceiver control for wired interface; and
a processing control based on given configuration.