METHOD AND APPARATUS FOR DYNAMIC MEDIA ACCESS CONTROL IN A MULTIPLE ACCESS SYSTEM
An electronic device may be operable to control access to a physical medium (e.g., airwaves, a copper cable, or an optical fiber) utilizing carrier sense multiple access (CSMA). The amount of time that the electronic device must sense the physical medium as being inactive before it permits transmission of a message onto the physical medium may be determined based on: the size of the message, the type of the message, the symbol rate at which the message is to be transmitted, and/or a channel onto which the message is to be transmitted. Similarly, other aspects of how and when electronic device transmits and/or receives on the physical medium may be controlled via one or more dynamically configurable parameters which may be configured based on characteristics of received and/or to-be-transmitted messages.
This patent application is a continuation of U.S. patent application Ser. No. 16/038,430, filed on Jul. 18, 2016, which is a continuation of U.S. patent application Ser. No. 15/200,265, filed on Jul. 1, 2016, which is a continuation of U.S. patent application Ser. No. 14/943,661, filed on Nov. 17, 2015, which is a continuation of U.S. patent application Ser. No. 13/408,453, filed on Feb. 29, 2012, which makes reference to, claims priority to and claims benefit from U.S. Provisional Patent Application Ser. No. 61/464,376, entitled “Advanced Communication System for Wide-area Low Power Wireless Applications and Active RFID” and filed on Mar. 2, 2011.
Each of the above identified applications is hereby incorporated herein by reference in its entirety.
INCORPORATION BY REFERENCEThis patent application also makes reference to:
U.S. Provisional Patent Application Ser. No. 61/464,376, entitled “Advanced Communication System for Wide-Area Low Power Wireless Applications and Active RFID” and filed on Mar. 2, 2011;
U.S. Provisional Patent Application Ser. No. 61/572,390, entitled “System for Adding Dash7-Based Applications Capability to a Smartphone” and filed on Jul. 15, 2011;
U.S. patent application Ser. No. 13/267,640, entitled “Method and Apparatus for Adaptive Searching of Distributed Datasets” and filed on Oct. 6, 2011;
U.S. patent application Ser. No. 13/267,621, entitled “Method and Apparatus for Low-Power, Long-Range Networking” and filed on Oct. 6, 2011;
U.S. patent application Ser. No. 13/270,802, entitled “Method and Apparatus for a Multi-band, Multi-mode Smartcard” and filed on Oct. 11, 2011;
U.S. patent application Ser. No. 13/270,959, entitled “Method and Apparatus for an Integrated Antenna” and filed on Oct. 11, 2011;
U.S. patent application Ser. No. 13/289,054, entitled “Method and Apparatus for Electronic Payment” and filed on Nov. 4, 2011;
U.S. patent application Ser. No. 13/289,050 filed on Nov. 4, 2011;
U.S. patent application Ser. No. 13/297,348, entitled “Method and Apparatus for Interfacing with a Smartcard” and filed on Nov. 16, 2011;
U.S. patent application Ser. No. 13/354,513, entitled “Method and Apparatus for Memory Management” and filed on Jan. 20, 2012;
U.S. patent application Ser. No. 13/354,615, entitled “Method and Apparatus for Discovering, People, Products, and/or Services via a Localized Wireless Network” and filed on Jan. 20, 2012;
U.S. patent application Ser. No. 13/396,708, entitled “Method and apparatus for Plug and Play, Networkable ISO 18000-7 Connectivity” and filed on Feb. 15, 2012;
U.S. patent application Ser. No. 13/396,739, entitled “Method and Apparatus for Serving Advertisements in a Low-Power Wireless Network” and filed on Feb. 15, 2012;
U.S. patent application Ser. No. 13/408,440, entitled “Method and Apparatus for Forward Error Correction (FEC) in a Resource-Constrained Network” and filed on Feb. 29, 2012;
U.S. patent application Ser. No. 13/408,447, entitled “Method and Apparatus for Adaptive Traffic Management in a Resource-Constrained Network” and filed on Feb. 29, 2012;
U.S. patent application Ser. No. 13/408,457, entitled “Method and Apparatus for Rapid Group Synchronization” and filed on Feb. 29, 2012;
U.S. patent application Ser. No. 13/408,461, entitled “Method and Apparatus for Addressing in a Resource-Constrained Network” and filed on Feb. 29, 2012;
U.S. patent application Ser. No. 13/408,464, entitled “Method and Apparatus for Query-Based Congestion Control” and filed on Feb. 29, 2012; and
U.S. patent application Ser. No. 13/408,466, entitled “Method and Apparatus for Power Autoscaling in a Resource-Constrained Network” and filed on Feb. 29, 2012.
Each of the above-referenced applications is hereby incorporated herein by reference in its entirety.
FIELD OF THE INVENTIONCertain embodiments of the invention relate to networking. More specifically, certain embodiments of the invention relate to a method and apparatus for dynamic media access control in a multiple access system.
BACKGROUND OF THE INVENTIONExisting methods of media access control for a shared communication medium are often inefficient. Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.
BRIEF SUMMARY OF THE INVENTIONA system and/or method is provided for dynamic media access control in a multiple access system, substantially as illustrated by and/or described in connection with at least one of the figures, as set forth more completely in the claims.
These and other advantages, aspects and novel features of the present invention, as well as details of an illustrated embodiment thereof, will be more fully understood from the following description and drawings.
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 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)}. 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)}. As utilized herein, the terms “block” and “module” refer to functions than can be implemented in hardware, software, firmware, or any combination of one or more thereof. As utilized herein, the term “exemplary” means serving as a non-limiting example, instance, or illustration. As utilized herein, the terms “e.g.,” and “for example,” introduce a list of one or more non-limiting examples, instances, or illustrations.
The CPU 204 may comprise circuitry operable to control operation of the first device 102. The CPU 204 may, for example, execute an operating system and/or other programs such (e.g., programs that enable a user interface of the device 102). The CPU 204 may generate one or more control signals for controlling the operation of the device 102. The CPU 204 may, for example, control a mode of operation of the device 102.
The CPU 214 may comprise circuitry operable to control operation of the second device 104. In some instances, the CPU 214 may be substantially similar to the CPU 204. In instances that the device 102 is less resource-constrained device, such as a base station or network controller, and the device 104 is more resource-constrained device, such as a battery-powered tag or a smartcard as described in above-incorporated U.S. patent application Ser. No. 13/270,802, the CPU 204 may be less-complex (e.g., comprise fewer gates, utilize less power, utilize less memory, etc.) than the CPU 214. In one embodiment, for example, the CPU 204 may comprise a RISC or ARM processor, and the CPU 214 may comprise a state-machine having a relatively small number of states (e.g., four states).
The radio 207 may comprise a processor 208 and an analog front-end (AFE) 209. The processor 208 may comprise circuitry operable to interface with the AFE 209 to receive and transmit data, and to process received and to-be-transmitted data. For transmission, the processor 208 may be operable to receive data from the CPU 204 and/or memory 206, encode, packetize, and/or otherwise process the data to prepare it for transmission in accordance with one or more wireless protocols, and output the data to the AFE 209 for transmission. For reception, the processor 208 may be operable to receive data via the AFE 209, process the received data and output received data to the memory 206 and/or the CPU 204. Exemplary protocols which may be supported by the second device 104 include the ISO 18000-7 standard, and protocols described in the above-incorporated U.S. Provisional Patent Application Ser. No. 61/464,376 filed on Mar. 2, 2011.
The radio 217 may comprise a processor 218 and an analog front-end (AFE) 219. The baseband processor 218 may comprise circuitry operable to interface with the AFE 219 to receive and transmit data, and to process received and to-be-transmitted data. In some instances, the baseband processor 218 may be substantially similar to the baseband processor 208. In instances that the device 102 is less-resource-constrained device, such as a base station or network controller, and the device 104 is a more-resource-constrained device, such as a battery-powered tag, the baseband processor 218 may be less-complex (e.g., comprise fewer gates, utilize less power, utilize less memory, etc.) than the baseband processor 208. In one embodiment, for example, the baseband processor 208 may be operable to implement more complex signal processing algorithms (e.g., FEC decoding) than the baseband processor 218.
The analog front-end (AFE) 209 may comprise circuitry suitable for processing received and/or to-be-transmitted data in the analog domain. For transmission, the AFE 209 may receive digital data from the baseband processor 208, process the data to generate corresponding RF signals, and output the RF signals to the antenna 210. For reception, the AFE 209 may receive RF signals from the antenna 210, process the RF signals to generate corresponding digital data, and output the digital data to the baseband processor 209. In some instances, the AFE 219 may be substantially similar to the AFE 209. In instances that the device 102 is less-resource-constrained device, such as a base station or network controller, and the device 104 is a more-resource-constrained device, such as a battery-powered tag, the AFE 219 may be less-complex (e.g., comprise fewer gates, utilize less power, utilize less memory, etc.) than the AFE 209. In one embodiment, for example, the AFE 209 may comprise a more-sensitive receiver, a more powerful transmitter than the AFE 219.
Circuitry of the memory 206 may comprise one or more memory cells and may be operable to store data to the memory cell(s) and read data from the memory cell(s). The one or more memory cell may comprise one or more volatile memory cells and/or one or more non-volatile memory cells. The memory 206 may store data arranged, for example, as an indexed short file block (ISFB) and/or indexed short file series block (ISFSB) as described in the above-incorporated U.S. Provisional Patent Application Ser. No. 61/464,376.
Circuitry of the memory 216 may comprise one or more memory cells and may be operable to read data from the memory cell(s) and/or store data to the memory cell(s). The memory 216 may store data arranged, for example, as an indexed short file block (ISFB) and/or indexed short file series block (ISFSB) as described in the above-incorporated U.S. Provisional Patent Application Ser. No. 61/464,376. In some instances, the memory 216 may be substantially similar to the memory 206. In instances that the device 104 is resource-constrained, the memory 216 may be less-complex (e.g., comprise fewer gates, utilize less power, etc.) than the memory 206.
Each of the clocks 211 and 221 may be operable to generate one or more oscillating signals which may be utilized to control synchronous circuitry of the device 100. Each of the clocks 211 and 221 may comprise, for example, one or more crystal oscillators, phase-locked loops, and/or direct digital synthesizers. Each of the clocks 211 and 221 may also comprise a “date/time” or “real-time” clock operable to keep track of time of day, day of week, day of month, month, and/or year.
The interfaces 212 and 222 may enable configuring and/or programming the devices 102 and 104, respectively. In an exemplary embodiment, one or more values of one or more timing parameters may be programmed via the programming interfaces 212 and/or 222.
Each of the antennas 210 and 220 may be operable to transmit and receive electromagnetic signals in one or more frequency bands. In an embodiment of the invention, the antennas 210 and 220 may be operable to transmit and receive signals in the ISM frequency band centered at 433.92 MHz.
In operation, the device 102 may be, for example, a base station or network controller, and the device 104 may be a mobile device such as a smart phone or a smartcard. The devices 102 and 104 may communicate via the radios 207 and 217. In communicating over the physical medium (e.g., the airwaves for wireless communication or a cable for wired communication), values of one or more media access control (MAC) parameters that control when and/or how to access the physical medium may be dynamic (i.e., configured “real-time” or “on-the-fly”). For example, values of one or more MAC parameters may be changed on a per-message and/or per-dialog (an exchange of one or more logically-related messages) basis. Exemplary MAC parameters whose values may be dynamically determined include: which channel(s) to transmit and/or receive on, whether to utilize CSMA, how long to listen before transmitting, how long to listen after transmitting, and/or how long a channel must be free before transmitting on that channel. Parameter values may, for example, change based on the contents of a message received over the medium and/or based on instructions stored locally (e.g., in memory 216 for the device 104). Such instructions may, for example, be generated by an application and/or operating system running on the device 102 and/or 104.
In operation, the device 104 may receive a request message and decide to transmit a response message in reply to the request message. For the transmission of the response message, the congestion control module 230 may receive a parameter TCA0, a parameter TG, a parameter CSMA_options, and a parameter ch_list. The parameters may be utilized directly in controlling access to the physical medium and/or utilized for determining values of other parameters which, in turn, may be utilized in controlling access to the physical medium. One or more of the parameters may have been received in, and/or derived from, information contained in the received request message. In this manner, the requesting device may control, at least in part, if, how, and/or when the responding device 104 transmits a response to the request.
The parameter ch_list may comprise a list of channel identifiers, where each channel identifier is uniquely associated with a particular combination of center frequency and bandwidth. The list of channels may correspond to channels on which the requesting device (i.e., the device that sent the request message) will listen for responses. The congestion control module 230 may modify the parameter ch_list to generate ch_list′ which may then be passed onto the CSMA module 236. The modification of ch_list to generate ch_list′ may be, for example, to remove one or more channels from the list because the device 104 is aware that the removed channel is highly congested, the device 104 does not support the channel, and/or for some other reason.
The parameter TCA0 may correspond to the amount of time that the device 104 has to begin transmitting the response message onto the physical medium. In an exemplary embodiment, TCA0 may correspond to TC−Tresp, where the value of TC (“contention period” or “response timeout”) is the amount of time that the requesting device is going to listen for responses to the request message (TC may have been received in the request message), and Tresp is the amount of time it will take the device 104 to transmit the response message.
The parameter CSMA_options may indicate whether to utilize carrier sense (i.e., whether to “listen before talk”) and/or which equations and/or algorithms the device 104 should utilize for calculating values for one or more timing parameters utilized by the CSMA module 236 and/or the congestion control module 230. Two exemplary parameters which may be calculated are TG′ (“guard time) and TCA (“collision avoidance timeout”). To illustrate, in an exemplary embodiment, TCA may be set equal to TCA0 for a first value of CSMA_options, but TCA may be set equal to TCA0/2 for a second CSMA_options. Other factors may additionally or alternatively be used for calculating TCA. Such factors may comprise, for example, characteristics (e.g., type and/or length) of the response message, and/or characteristics (e.g., data rate, frequency, bandwidth, modulation type, and/or symbol rate) of the channel onto which the response message is to be transmitted. After calculating TCA, the congestion control module 230 may store the value of TCA in the register 234.
The parameter TG may be an initial value for a parameter TG′ (“guard time”). TG′ which may determine how long the device 104 must sense the physical medium as being inactive before the device 104 begins transmitting the response message onto the physical medium. Other factors in determining a value of TG′ may include CSMA_options, TCA, TCA0, characteristics (e.g., type and/or length) of the response message, and/or characteristics (e.g., data rate, frequency, bandwidth, modulation type, and/or symbol rate) of the channel onto which the response message is to be transmitted.
Upon initialization from the congestion control module 230, the CSMA module 236 may perform CSMA as, for example, described below in reference to
In step 304, the device 102 determines a value of one or more parameters that instruct devices receiving the request as to if, how, and/or when to send responses to the request message. For example, the device 102 may determine a value of TC (the amount of time it will listen for responses to the request), CSMA_options (a flag which indicates an equation and/or algorithm that responding devices should use when calculating values for certain timing parameters), and a list of one or more channels on which the device 102 will listen for responses. The device 102 may determine TC, CSMA_options, and/or the channel list based on, for example: the type of request, the symbol rate of the channel(s) over which the request will be transmitted and/or responses received, the results of past requests (e.g., knowledge about the devices that have responded to past requests), the location of the device 102 (e.g., based on received GPS signals, other wireless signals, and/or user input), the number or responses that are desired, and/or any other suitable criteria. For example, the device 102 may set TC to a larger value if it wants to receive many and/or long responses, and may set TC to a smaller value if it wants to receiver fewer and/or shorter responses.
In step 306, the device 102 inserts the value(s) of the one or more parameters calculated in step 304 into one or more fields of the request message. In step 308, the device 102 transmits the request message. In an exemplary embodiment, the device 102 may perform CSMA and transmit the request message only upon sensing that the medium is free. In such instances, timing parameters utilized as part of the CSMA process may be the same as the values calculated for the potential response messages, or may be different. For example, first values of timing parameters, such as TCA and TG′, may be utilized when transmitting request messages whereas second values of timing parameters, such as TCA and TG′, may be utilized when transmitting response messages. In another exemplary embodiment, for request messages, the device 102 may not sense whether another device is already transmitting because, for example, it may not care whether a collision occurs or may know (e.g., through scheduling) that the medium is free.
In step 310, the request message is received by the device 104. In step 312, the device 104 processes the received request message and decides to transmit a response message. In step 314, the device 104 determine values of TCA and TG′ to be utilized for transmitting the response message. The value of TCA for the response message may be calculated, for example, as described above with respect to
Referring now to
Returning to step 316, if the value of TCA is greater than the threshold, then, in step 320, the congestion control module 230 triggers the CSMA process performed by the CSMA module 236. In step 322, the CSMA process described below with respect to
Returning to step 324, if the step 322 did not result in a successful transmission, then the exemplary steps advance to step 326. In step 326, the congestion control module counts down an amount of time Twait. The value of Twait may be calculated based on variety of factors such as, for example, CSMA_options, TCA0, TCA, TG′, the length of the response message, the type (e.g., foreground or background) of the response message, the symbol rate at which the response message is to be transmitted, and/or a search score generated by comparing a received search token with locally stored data.
In step 328, the value stored in the TCA register 234 is updated. In an exemplary embodiment, the value stored in the register 234 may be updated by subtracting off the amount of time that has elapsed since the value was calculated. In another exemplary embodiment, a new value of TCA may be calculated based on, for example, CSMA_options, TG,′ and/or on how much time is left in the contention period (the time period of duration TC during which the requesting device will listen for responses).
Referring now to
Returning to step 342, if CSMA is enabled, then in step 344, a variable i is set to 1. In step 346, the physical layer receiver of the device 104 is powered-up and configured to receive on the ith channel identified by the parameter ch_list′. In step 348, the CSMA module 236 detects whether CS from the physical layer is asserted. The PHY may assert CS when the received signal strength is above a threshold. The threshold utilized by the RSSI module 238 may have been pre-configured by an administrator and/or configured dynamically based on, for example, past performance and/or based on information contained in the received request message. If CS is not asserted, then in step 350, the CSMA module 236 waits for a period of time equal to TG′. In step 352, the CSMA module 236 again detects whether CS from the physical layer is asserted. If CS is not asserted then, in step 356 the CSMA module 236 asserts TxEN. In step 358 the flow control module 232 manages the transmission of the response message onto the physical medium.
Returning to steps 348 and 352, if either of these steps detect that CS is asserted, then the exemplary steps advance to step 362. In step 362, the variable i is incremented by 1. In step 364, the value of TCA in register 236 is updated by subtracting off the amount of time that has elapsed since the register was last programmed. In step 366, the updated value of TCA is compared to a threshold (i.e. it is determined whether there would still be time to transmit the response message before the contention period ends). If not, then in step 370, TxEN remains deasserted and the steps advance to step 360. If so, then in step 368 it is determined whether all channels in the channel list have been checked for availability. If not, then the exemplary steps return to step 346. If all channels have been checked, then the exemplary steps advance to step 370.
In step 420, the device may receive any remaining bits of the frame. In step 422, the device 104 may parse one or more fields of the received frame to determine whether the device 104 was an intended recipient of the frame and/or whether the device 104 cares about the frame (i.e., wants to devote resources to further processing the message). Frames not intended for the device 104 and/or not of interest to the device 104 may be discarded without further processing. In step 424, if there are additional frames to be received then the steps may return to step 420. If there are no additional frames to receive then in step 426 the device 104 may determine whether the received packet passes (i.e. is not dropped during) MAC filtering. If not, then the device 104 may return to step 408 in which it may re-evaluate TSD and reinitialize reception. If so, then the device 104 may transition to a transmit state (e.g., as described in portions of
Although
Referring to
Referring to
In operation, upon entering an idle state of operation (e.g., at a time triggered by a real-time clock), the device 104 may read the first scan n-tuple 6021, listen to the channel identified by field 6041 of scan n-tuple 6021 for the type of frame identified in field 6042 of scan n-tuple 6021. The device 104 may begin counting-down the amount of time in field 6044 while concurrently beginning listening for the amount of time in field 6043. After the longer of these two time fields expires, the device 104 may read the next scan n-tuple 6022 in the sequence 606 and operate accordingly, that is, enter a listen state followed by a wait state according to the fields of the scan n-tuple 6022. The device 104 may repeat this process until it has operated in accordance with each of the scan n-tuples 6021-602M. After completing the scan described in the last n-tuple of the sequence 606, the device may return to the first n-tuple in the sequence 614.
Referring to
Referring to
In operation, upon entering a beacon transmit state of operation (e.g., at a time triggered by a real-time clock), the device 104 may read the first beacon n-tuple 6101 and transmit a beacon comprising: data pointed to by field 6123 of n-tuple 6101; and fields determined by field 6123 of beacon n-tuple. The device may then listen for responses to the beacon for the amount of time indicated in field 6124 of n-tuple 6101. The device may repeat the beacon up to the number of times in field 6125 of n-tuple 6101 until a response is received or until the amount of time TNB in field 6126 of n-tuple 6101 elapses. After a response is received, or TNB elapses, the device 104 may read the next n-tuple 6102 in the sequence 614 and operate accordingly, that is, enter a transmit state followed by a listen state and/or a wait state according to the fields of the n-tuple 6102. The device 104 may repeat this process until it has operated in accordance with each of the n-tuples 6101-610M. After completing beacon transmission in accordance with the last n-tuple in the sequence 614, the device may exit the beacon transmit mode of operation or may return to the first n-tuple in the sequence 614.
The n-tuples, sequences, and states of operation described with respect to
The sequences 6061 and 6062 may be instances of the sequence 606 described in
The sequences 6141 and 6142 may be instances of the sequence 614 described in
The portion 702 may store values of one or more parameters such as, for example, parameters which configure the congestion control module 230, the flow control module 232, the CSMA module 236, and/or the RSSI module 238. Such parameters may, for example, be programmed into the portion 702 by a system administrator and/or may be configured based on received request messages.
The portion 704 may store data as, for example, described with reference to the indexed short file block (ISFB), the indexed short file series block (ISFSB), and/or the generic file block (GFB) described in the above-incorporated U.S. Provisional Patent Application Ser. No. 61/464,376.
In step 810, the PHY of the device 104 may be configured according to the Channel ID. That is, the center frequency and bandwidth of the receiver may be configured according to the Channel ID.
In step 812, the device 104 may listen for a sync word that corresponds to the scan type of the scan i. If the scan duration elapses, and/or if the received signal strength on the channel being scanned goes below a threshold value (which may be configurable), without receiving the sync word, then in step 813 the device 104 may wait for the remainder of TNS, which may have started counting in step 806 or 808 (e.g., if 100 milliseconds have elapsed since the n-tuple 602i was retrieved, then the device may wait for TNS−100 ms in step 813).
In step 814 it may be determined whether i has reached a maximum value. The maximum value of i may be, for example, M+1 (where M is the number of n-tuples in the sequence 606). If i has not reached its maximum value, then, in step 816, i may be incremented and the steps may return to step 806.
Returning to step 814, if i has reached its maximum value, then in step 818 the scan sequence may be complete. Upon completing the scan sequence, the device 104 may, for example, begin a new scan sequence, begin a beacon transmit sequence, or go into a sleep mode.
Returning to step 812, if a sync word of the type being listened for is received before the scan duration times out, then in step 820 the device 104 will receive one or more frames and, in step 822, process the received frame(s). If in step 822 one or more of the received frames are dropped during MAC filtering, step 812 may be resumed.
Returning to step 918, if R is less than or equal to zero, then in step 920 the device may wait for the remainder of TNB, which may have started counting in step 906 or 908 (e.g., if 100 milliseconds have elapsed since the n-tuple 602i; was retrieved, then the device may wait for TNB−100 ms in step 920). In step 922, it may be determined whether i has reached a maximum value. The maximum value of i may be, for example, the number of n-tuples in a sequence 614. If i has not reached its maximum value and no acknowledgement was detected in step 914, then, in step 924, i may be incremented and the steps may return to step 906.
Returning to step 922, if i has reached its maximum value, then in step 926 the beacon transmit sequence may be complete. Upon completing the beacon transmit sequence, the device 104 may, for example, begin a new beacon transmit sequence, begin a scan sequence, or go into a sleep mode.
Referring to
Referring to
In
Thus, as illustrated in
Additional details of the frames and fields described above with respect to
In accordance with various aspects of the present invention, an electronic device 104 may be operable to control access to a physical medium (e.g., airwaves, a copper cable, or an optical fiber) utilizing carrier sense multiple access (CSMA). The amount of time that the electronic device 104 must sense the physical medium as being inactive before it permits transmission of a message onto the physical medium may be determined based on: the size of the message, the type of the message, the symbol rate at which the message is to be transmitted, and/or a channel onto which the message is to be transmitted. Similarly, how long and/or how many times the electronic device attempts to transmit the message may be based the size of the message, the type of the message, the symbol rate at which the message is to be transmitted, and/or a channel onto which the message is to be transmitted.
The message may be in response to a request received by the electronic device via the physical medium, and the channel onto which the message is to be transmitted may be determined based on a field (e.g., Response Channel List) of the received request. The field of the received request may comprises a list of channels, and the electronic device 104 may sequentially listen to channels in the list until a channel meeting certain requirements (e.g., signal strength below a threshold for at least a period of time TG′) is found or until a timeout occurs (e.g., TCA has elapsed since a CSMA process was initiated or TC has elapsed since the request was sent). The maximum amount of time that the electronic device 104 attempts to transmit the message onto the physical medium may be determined based on a field (e.g., Response timeout) of the received request message. While the message is pending transmission, a portion of the electronic device 104 may alternate between a listen state and a wait state, wherein the amount of time in one or both of the listen state and the wait state may be determined based on one or more fields (e.g., Response timeout and/or CA type) of the received request. Additionally or alternatively, the one or more fields of the received request may determine an equation and/or algorithm utilized by the electronic device for the determining the amount of time spent in one or both of the listen state and the wait state.
The electronic device 104 may comprise memory and a receiver and may be operable to: read a series of n-tuples from the memory, each of the n-tuple comprising a channel identifier, a scan duration value, and a time-to-next-scan value. For each of the read n-tuples, the device 104 may be operable to: configure the receiver to receive on the channel associated with the channel identifier for an amount of time equal to the scan duration value; and power-down the receiver for an amount of time equal to the time-to-next-scan value minus the scan duration value.
The electronic device 104 may comprise a memory, a transmitter, and a receiver and may be operable to read a series of n-tuples from the memory, each of the n-tuple comprising a channel identifier, a contention period value, and a time-to-next-scan value. For each of the read n-tuples, the device 104 may be operable to: configure the transmitter to transmit a beacon on the channel associated with the channel identifier; configure the receiver to listen for a response to the beacon for an amount of time equal to the contention period value; and wait a period of time equal to the time-to-next-scan value minus the contention period value before operating based on the next n-tuple in the series of n-tuples.
Other embodiments of the invention may provide a non-transitory computer readable medium and/or storage medium, and/or a non-transitory machine readable medium and/or storage medium, having stored thereon, a machine code and/or a computer program having at least one code section executable by a machine and/or a computer, thereby causing the machine and/or computer to perform the steps as described herein for dynamic media access control in a multiple access system.
Accordingly, the present invention may be realized in hardware, software, or a combination of hardware and software. The present invention 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.
The present invention may also be embedded in a computer program product, which comprises all the features enabling the implementation of the methods described herein, and which when loaded in a computer system is able to carry out these methods. Computer program in the present context means any expression, in any language, code or notation, of a set of instructions intended to cause a system having an information processing capability to perform a particular function either directly or after either or both of the following: a) conversion to another language, code or notation; b) reproduction in a different material form.
While the present invention has been described with reference to certain embodiments, 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 invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present invention without departing from its scope. Therefore, it is intended that the present invention not be limited to the particular embodiment disclosed, but that the present invention will include all embodiments falling within the scope of the appended claims.
Claims
1. A system comprising:
- an electronic device operable to control access to a physical medium utilizing carrier sense multiple access (CSMA), wherein the amount of time that said electronic device must sense said physical medium as being inactive before said electronic device permits transmission of a message onto said physical medium is determined based on the size of said message.
2. The system of claim 1, wherein said amount of time that said electronic device must sense said physical medium as being inactive before said electronic device permits transmission of said message onto said physical medium is determined based on a type of said message.
3. The system of claim 1, wherein said amount of time that said electronic device must sense said physical medium as being inactive before said electronic device permits transmission of said message onto said physical medium is determined based on a symbol rate at which said message is to be transmitted.
4. The system of claim 1, wherein said amount of time that said electronic device must sense said physical medium as being inactive before said electronic device permits transmission of said message onto said physical medium is determined based on a channel onto which said message is to be transmitted.
5. The system of claim 1, wherein:
- said message is in response to a request received by said electronic device via said physical medium; and
- said channel onto which said message is to be transmitted is determined based on a field of said received request.
6. The system of claim 5, wherein:
- said field of said received request comprises a list of channels;
- said electronic device sequentially listen to channels in said list of channels until a channel meeting certain requirements is found or until a timeout occurs.
7. The system of claim 1, wherein:
- said message is in response to a request received via said physical medium by said electronic device; and
- the maximum amount of time that said electronic device attempts to transmit said message onto said physical medium is determined based on a field of said previously-received request message.
8. The system of claim 1, wherein:
- said message is in response to a request received via said physical medium by said electronic device; and
- while said message is pending transmission, a portion of said electronic device alternates between a listen state and a wait state, wherein the amount of time that said portion of said electronic device spends in one or both of said listen state and said wait state is determined based on one or more fields of said received request.
9. The system of claim 8, wherein said one or more fields of said received request determine an equation and/or algorithm utilized by said electronic device for said determining said amount of time that said portion of said electronic device spends in one or both of said listen state and said wait state.
10. The system of claim 1, wherein said electronic device comprises memory and a receiver and is operable to:
- read a series of n-tuples from said memory, each of said n-tuple comprising a channel identifier, a scan duration value, and a time-to-next-scan value; and
- for each of said read n-tuples: configure said receiver to receive on the channel associated with said channel identifier for an amount of time equal to said scan duration value; and power-down said receiver for an amount of time equal to said time-to-next-scan value minus said scan duration value.
11. The system of claim 1, wherein said electronic device comprises memory, a transmitter, and a receiver and is operable to:
- read a series of n-tuples from said memory, each of said n-tuple comprising a channel identifier, a contention period value, and a time-to-next-scan value; and
- for each of said read n-tuples: configure said transmitter to transmit a beacon on the channel associated with said channel identifier; configure said receiver to listen for a response to said beacon for an amount of time equal to said contention period value; and wait a period of time equal to said time-to-next-scan value minus said contention period value before operating based on the next n-tuple in said series of n-tuples.
12. A method comprising:
- in an electronic device which utilizes carrier sense multiple access (CSMA) for communicating over a physical medium: determining the amount of time that said electronic device must sense said physical medium as being inactive before permitting transmission of a message onto said physical medium based on the size of said message.
13. The method of claim 12, wherein said determining said amount of time that said electronic device must sense said physical medium as being inactive before said electronic device permits transmission of said message onto said physical medium is based on a type of said message.
14. The method of claim 12, wherein said determining said amount of time that said electronic device must sense said physical medium as being inactive before said electronic device permits transmission of said message onto said physical medium is based on a symbol rate at which said message is to be transmitted.
15. The method of claim 12, wherein said determining said amount of time that said electronic device must sense said physical medium as being inactive before said electronic device permits transmission of said message onto said physical medium is based on a channel onto which said message is to be transmitted.
16. The method of claim 12, wherein:
- said message is in response to a request received by said electronic device via said physical medium; and
- said channel onto which said message is to be transmitted is determined based on a field of said received request.
17. The method of claim 16, wherein:
- said field of said received request comprises a list of channels;
- said electronic device sequentially listen to channels in said list of channels until a channel meeting certain requirements is found or until a timeout occurs.
18. The method of claim 12, wherein:
- said message is in response to a request received via said physical medium by said electronic device; and
- the maximum amount of time that said electronic device attempts to transmit said message onto said physical medium is determined based on a field of said previously-received request message.
19. The method of claim 12, wherein:
- said message is in response to a request received via said physical medium by said electronic device; and
- while said message is pending transmission, a portion of said electronic device alternates between a listen state and a wait state, wherein the amount of time that said portion of said electronic device spends in one or both of said listen state and said wait state is determined based on one or more fields of said received request.
20. The method of claim 19, wherein said one or more fields of said received request determine an equation and/or algorithm utilized by said electronic device for said determining said amount of time that said portion of said electronic device spends in one or both of said listen state and said wait state.
Type: Application
Filed: Mar 1, 2019
Publication Date: Jun 27, 2019
Inventor: John Peter Norair (San Francisco, CA)
Application Number: 16/290,605