Time and frequency allocation for concurrent communications on a shared coaxial cable

This application claims priority to and the benefit of the following application(s), each of which is hereby incorporated herein by reference:

U.S. provisional patent application 62/190,448 titled “Time and Frequency Allocation for Concurrent Communications on a Shared Coaxial Cable” filed on Jul. 9, 2015.

Limitations and disadvantages of conventional approaches to time and frequency allocation for concurrent communications on a shared coaxial cable will become apparent to one of skill in the art, through comparison of such approaches with some aspects of the present method and system set forth in the remainder of this disclosure with reference to the drawings.

Methods and systems are provided for time and frequency allocation for concurrent communications on a shared coaxial cable, substantially as illustrated by and/or described in connection with at least one of the figures, as set forth more completely in the claims.

FIG. 1 depicts an example multimedia over coax alliance (MoCA) network adapted in accordance with aspects of this disclosure in order to permit concurrent communications among multiple pairs of nodes.

FIG. 2 is a block diagram of a MoCA network controller adapted to provide bandwidth grants on both a time and a frequency basis.

FIG. 3 depicts example data structures which the MoCA network controller of FIG. 2 may use for granting reservation requests.

FIG. 4 is a flowchart illustrating an example request grant process performed by the MoCA network controller of FIG. 2 .

FIG. 5 illustrates an example allocation of timeslot and subband using per-pair link parameters and per-pair grant status data structures.

FIG. 1 depicts an exemplary MoCA network. Shown in FIG. 1 is a local area network (LAN) 100 connected to a network 114 . The exemplary LAN 100 comprises a device 102 (e.g., a gateway device and/or network controller device, etc.) and network devices 104 a - 104 c coupled via links 106 a - 106 f and splitters 108 a - 108 b . The LAN 100 also comprises devices 110 a and 110 b coupled to respective network devices 104 a and 104 c via links 112 a and 112 b , respectively.

Each of the links 106 a - 106 f may, for example, comprise wired cabling, optical cabling, and/or wireless links. In an exemplary embodiment, each of the links 106 a - 106 f comprises coaxial cabling. The splitter 108 a is operable to electrically couple links 106 a , 106 b , 106 c , and 106 f such that the signal on each of these four links is substantially the same. The splitter 108 b is operable to electrically couple links 106 c , 106 d , and 106 e such that the signal on each of these three links is substantially the same.

The device 102 comprises circuitry operable to communicate over the links 106 a - 106 f . The circuitry of the device 102 may also be operable to communicate with network 114 (e.g., a CaTV network, a DSL network, a satellite network, etc.). The device 102 may be, for example, a set-top box or gateway operable to receive data from the network 114 via the links 106 f and 106 b , process the received data, and convey the processed data to the devices 104 a - 104 c via the links 106 a - 106 e . In an exemplary embodiment, the device 102 may communicate the processed data over the links 106 a - 106 e in accordance with multimedia over coaxial alliance (MoCA) standards, such as the “MoCA MAC/PHY Specification v2.0 MoCA-M/P-SPEC-V2.0-20100507,” which is hereby incorporated herein by reference in its entirety. In such an embodiment, the device 102 may function as the network coordinator (NC) of the MoCA network.

Each of the example devices 104 a - 104 c may comprise circuitry operable to communicate over the links 106 a - 106 e . The device 104 c may be, for example, a wireless access point operable to convert between the network protocols (e.g., MoCA, etc.) utilized on the links 106 a - 106 e and the network protocols (e.g., IEEE 802.11, Bluetooth, etc.) utilized on the link 112 b . The device 104 a may be, for example, a network adaptor operable to convert between the network protocols (e.g., MoCA, etc.) utilized on the links 106 a - 106 e and the network protocols (e.g., HDMI, USB, Ethernet, etc.) utilized on the link 112 a.

The devices 110 a and 110 b may comprise circuitry operable to receive media and/or data via the links 112 a and 112 b , respectively. The devices 110 a and 110 b may comprise circuitry operable to transmit media and/or data via the links 112 a and 112 b , respectively. Each of the devices 110 a and 110 b may be, for example, an end-point such as a television or personal computer.

In operation, a device 104 (representing any of 104 a , 104 b , and 104 c ) desiring to transmit to another device 104 (representing any other of 104 a , 104 b , and 104 c ) sends a reservation request (or request to transmit) to the network controller 102 . The network controller 102 then grants or denies the reservation request. If the reservation request is granted, the grant may include an assignment of both: one or more timeslots on which the transmission is to take place, and one or more frequency bands on which the transmission is to take place. Including a frequency assignment in the grant enables multiple pairs of MoCA nodes to communicate concurrently (or simultaneously) on different frequencies.

The determination of whether to grant the reservation request and, if so granted, the determination of which timeslot(s) and frequency(ies) to allocate for the grant, may be based on one or more factors including, for example: the identity of the device that would be transmitting, the identity(ies) of the intended destination device(s), link parameters that would be used for the transmission, identities of transmit and destination devices for other pending reservation requests, link parameters that would be used for the other pending reservation requests, identities of transmit and destination devices for previously granted reservation request (where transmissions are ongoing or scheduled for some time in the future), and/or link parameters used for the previously-granted reservation requests.

FIG. 2 is a block diagram of a MoCA network controller (NC) adapted to provide bandwidth grants on both a time and a frequency basis. The example network controller comprises a transceiver 202 and chipset 204 .

The transceiver 202 is configured for transmitting and receiving over the cable 106 using both time and frequency division multiplexing. The transceiver 202 may be operable to measure signal quality metrics (e.g., signal-to-noise ratio, etc.) for the coaxial cable 106 , and report the measured metrics to the chipset 204 .

The chipset 204 comprises a processor (e.g., x86 based, ARM based, an FPGA, ASIC, etc.) 206 , memory 208 (e.g., DRAM, nonvolatile storage, a non-transitory machine-readable storage medium, etc.), and peripheral circuitry 210 (e.g., bus adaptor(s), LAN adaptor(s), etc.).

The processor 206 , using memory 208 , operates to decide whether to grant or deny reservation requests received via transceiver 202 , determine which timeslot(s) and frequency(ies) to allocate for granted reservation requests, and to provide grant or denial messages to the transceiver 202 for transmission onto the cable 106 . This may comprise the processor 206 performing the process described below with reference to FIG. 4 using the data structures shown in FIG. 3 .

FIG. 3 depicts example data structures which the MoCA network controller of FIG. 2 may use for granting reservation requests. Shown are a link parameters data structure 302 and a grant status data structure 304 .

The data structure 302 (e.g., a lookup table stored in memory 208 ) stores sets of link parameters for each possible pair of M devices on the shared (shared among the MoCA network and one or more networks such as a CaTV network) communication medium 106 (e.g., in FIG. 1 , M=4 and the four devices are 102 , 104 a , 104 b , and 104 c ). Each set of link parameters (LP x,y ) may include, for example, a minimum transmit power needed for a transmission from device ‘x’ to reach device ‘y’ (i.e., the more attenuation between a transmitting device and a receiving device, the more transmit power that will be needed), and spectral characteristics of the link between the device ‘x’ and device ‘y’ (e.g., SNR over frequency (e.g., in list or table form for a plurality of frequencies), noise level, power spectral density (e.g., in list or table form for a plurality of frequencies), and/or other measurement(s) for each of a plurality of possible subbands). The per-pair link parameters may, for example, be determined through the use of probes communicated among each pair of devices on the network.

The data structure 304 (e.g., a lookup table stored in memory 208 ), stores status/characterizations of reservation requests. For each possible pair of M devices, the table 304 indicates whether a reservation request is pending or granted. Where no reservation request is pending or granted for transmissions from device ‘x’ to device ‘y’, the corresponding entry in table 304 indicates “none;” where a reservation request is pending for a transmission from device ‘x’ to device ‘y’, the corresponding entry in table indicates “pending;” and where a reservation request has been granted, the corresponding entry holds (T,F) x,y , where ‘T’ is the timeslot(s) that has been allocated for the transmission (e.g., referenced to some determined network clock) and F is the subband(s) that have been allocated for the transmission.

FIG. 4 is a flowchart illustrating an example reservation request grant process performed by the MoCA network controller of FIG. 2 . The process begins with block 402 in which the network controller (e.g., device 102 ) receives a reservation request from device ‘x’ (e.g., device 104 a ) seeking to transmit to device ‘y’ (e.g., device 104 b ). In block 404 , the network controller accesses per-pair link parameter table 302 and per-pair grant status table 304 to determine subband(s) F, timeslot(s) T, and link parameters, LP x,y which can be used for the transmission from device ‘x’ to device ‘y’ while keeping any interference (from the transmission from device ‘x’ to device ‘y’ onto other transmissions, and the interference from other transmissions onto the transmission from device ‘x’ to device ‘y’) at tolerable levels (e.g., where tolerable levels may be defined as keeping error rates below a determined threshold). In block 406 , the network controller grants the reservation request. Accordingly, in block 408 , the network controller 102 stores F and T to the table 304 and stores LP x,y to the table 302 ; and in block 410 , the network controller instructs ‘x’ to carry out the transmission using link parameters LP x,y on subband(s) F during timeslot(s) T.

FIG. 5 illustrates an example allocation of timeslot and subband using per-pair link parameters and per-pair grant status data structures. In FIG. 5 , device 104 b has requested a reservation for a transmission to device 104 c . Before the allocation, existing allocations are shown in tables 504 and 506 for timeslots T 1 and T 2 , respectively. In this hypothetical example, the network controller 102 has three subbands, F 1 -F 3 , available for allocation. In determining whether to assign the requested communication from 104 b to 104 c to timeslot T 1 or T 2 , the network controller 102 inspects the data structures to determine that all three subbands are already allocated for timeslot T 1 , thus the communication is assigned to timeslot T 2 . To decide which subband to allocate during timeslot T 2 , the network controller 102 takes into consideration that F 1 has already been allocated for a communication from 104 a to 104 b . As a result of the physical topology of the network ( 104 a and 104 b are far apart) the per-pair link parameters for the communication from 104 a and 104 b inform the network controller that the device 104 a will have to use high transmit power for that communication. As a result, some of that transmission may leak onto subband F 2 . Accordingly, the network controller decides to allocate F 3 for the communication from 104 b to 104 c during timeslot T 2 , as shown in 510 .

In accordance with an example implementation of this disclosure, circuitry (e.g., circuitry or chipset 204 ) for use in a network controller (e.g., device 102 ) comprises a processor (e.g., 206 ) and memory (e.g., 208 ). The network controller is operable to control communications in a network comprising a plurality of devices (e.g., 104 a , 104 b , and 104 c ) connected via a shared coaxial cable (e.g., 106 a - 106 f ). The circuitry is operable to maintain one or more data structures (e.g., read and write data structures 302 and 304 in memory 208 ) that hold per-sender-receiver-pair link parameters and per-sender-receiver-pair bandwidth grant status. The circuitry is operable to, in response to receipt of a reservation request (or a request to transmit) on the shared coaxial cable, decide which one or more of a plurality of subbands (e.g., which one or more of F 1 -F 3 in the example of FIG. 5 ) and which one or more of a plurality timeslots (e.g., the timeslots T 1 and T 2 in the example of FIG. 5 ) to reserve for the transmission based, at least in part, on the per-sender-receiver-pair link parameters and the per-sender-receiver-pair bandwidth grant status in the one or more data structures. The circuitry is operable to generate a reservation grant message that indicates the decided one or more subbands and the decided one or more timeslots. The per-sender-receiver-pair link parameters comprise a minimum transmit power parameter for each sender-receiver pair of the plurality of devices (e.g., for the example of FIG. 5 , each of the following sender-receiver pairs: ( 104 a , 104 b ), ( 104 b , 104 a ), ( 104 b , 104 c ), ( 104 c , 104 b ), ( 104 a , 104 c ), and ( 104 c , 104 a ). The per-sender-receiver-pair link parameters may, for example, comprise a minimum transmit power parameter for each sender-receiver pair of the plurality of devices. The processor and memory may, for example, be operable to determine the per-sender-receiver-pair link parameters based at least in part on probes communicated over the shared coaxial cable by the plurality of devices. The per-sender-receiver-pair grant status may, for example, indicate a reserved one or more subbands and a reserved one or more timeslots for each of a plurality of granted reservation requests. The circuitry may, for example, be operable to reserve a first subset of the plurality of subbands (e.g., F 1 in the example of FIG. 5 ) during a particular timeslot (e.g., timeslot T 2 in the example of FIG. 5 ) for a first granted reservation request, and reserve a second subset of the plurality of subbands (e.g., F 3 in the example of FIG. 5 ) during the particular timeslot for a second granted reservation request such that communications of the first granted reservation request and of the second granted reservation request are to occur concurrently (or simultaneously) on the shared coaxial cable. The per-sender-receiver-pair link parameters may comprise link parameters used for previous communications on the shared coaxial cable. The per-sender-receiver-pair link parameters may comprise link parameters to be used for future communications on the shared coaxial cable. The circuitry may comprise a transceiver (e.g., 202 ) operable to measure a performance metric on the shared coaxial cable, and make the measured performance metric available to the processor. The processor may be operable to update the one or more data structures based, at least in part, on the measured performance metric.

As utilized herein the terms “circuits” and “circuitry” refer to physical electronic components (i.e. hardware) and any software and/or firmware (“code”) which may configure the hardware, be executed by the hardware, and or otherwise be associated with the hardware. As used herein, for example, a particular processor and memory may comprise a first “circuit” when executing a first one or more lines of code and may comprise a second “circuit” when executing a second one or more lines of code. As utilized herein, “and/or” means any one or more of the items in the list joined by “and/or”. As an example, “x and/or y” means any element of the three-element set {(x), (y), (x, y)}. In other words, “x and/or y” means “one or both of x and y”. As another example, “x, y, and/or z” means any element of the seven-element set {(x), (y), (z), (x, y), (x, z), (y, z), (x, y, z)}. In other words, “x, y and/or z” means “one or more of x, y and z”. As utilized herein, the term “exemplary” means serving as a non-limiting example, instance, or illustration. As utilized herein, the terms “e.g.,” “for example,” “exemplary,” and the like, set off lists of one or more non-limiting examples, instances, or illustrations. As utilized herein, circuitry is “operable” to perform a function whenever the circuitry comprises the necessary hardware and code (if any is necessary) to perform the function, regardless of whether performance of the function is disabled or not enabled (e.g., by a user-configurable setting, factory trim, etc.).

The present method and/or system may be realized in hardware, software, or a combination of hardware and software. The present methods and/or systems may be realized in a centralized fashion in at least one computing system, or in a distributed fashion where different elements are spread across several interconnected computing systems. Any kind of computing system or other apparatus adapted for carrying out the methods described herein is suited. A typical combination of hardware and software may be a general-purpose computing system with a program or other code that, when being loaded and executed, controls the computing system such that it carries out the methods described herein. Another typical implementation may comprise an application specific integrated circuit or chip. Some implementations may comprise a non-transitory machine-readable (e.g., computer readable) medium (e.g., FLASH drive, optical disk, magnetic storage disk, or the like) having stored thereon one or more lines of code executable by a machine, thereby causing the machine to perform processes as described herein.

While the present method and/or system has been described with reference to certain implementations, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the present method and/or system. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from its scope. Therefore, it is intended that the present method and/or system not be limited to the particular implementations disclosed, but that the present method and/or system will include all implementations falling within the scope of the appended claims.