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    • 专利摘要:
      TEMPORAL SYNCHRONIZATION METHOD IN A WIRELESS COMMUNICATION SYSTEM, WIRELESS COMMUNICATION SYSTEM, AND WIRELESS RECEIVERTime synchronization in a wireless communication system comprises the transmission of a synchronization frame from a transmitter to a receiver through a wireless communication medium. The synchronization board includes a time stamp indicating the local time of the transmitter when a symbol at a predefined position on the synchronization board is placed on the wireless communication medium for transmission. The synchronization frame is received at the receiver which determines a reception time comprising the local time of the receiver when the symbol of the synchronization frame was received at the physical layer of the receiver. Time synchronization is performed by determining a difference between the time stamp and the receiving time, and adjusting the receiver's local time based on the difference to synchronize the receiver with the transmitter in time.
    公开号:BR112012022397A2
    申请号:R112012022397-6
    申请日:2011-03-04
    公开日:2020-09-01
    发明作者:Huai-Rong Shao；Ju-Lan Hsu；Chiu Ngo
    申请人:Samsung Electronics Co., Ltd.；
    IPC主号:
    专利说明:

    TEMPORAL SYNCHRONIZATION METHOD IN A WIRELESS COMMUNICATION SYSTEM AND WIRELESS RECEIVER
    TECHNICAL FIELD The present invention relates to clock synchronization between communication devices and, particularly, it relates to the exact clock synchronization for a device communicating in wireless networks.
    BACKGROUND OF THE TECHNIQUE The specifications of the IEEE 802.11 wireless communication protocol for wireless networks define a time synchronization scheme for wireless stations on a wireless network. A wireless access point (AP) station can read a system clock by generating a flag and placing time information on the sign board. DISCLOSURE OF THE INVENTION
    SOLUTION TO THE PROBLEM Modes of the present invention provide a method and system for highly accurate clock synchronization protocol for communication between devices in a communication system such as a wireless communication system comprising a wireless network.
    ADVANTAGE EFFECTS OF THE INVENTION In accordance with the modalities of the present invention,
    i when a packet is created by the MAC layer in the AP, the packet: receives a time stamp with the local clock time when the packet reaches the PHY layer of AP for transmission through the channel, more properly than the S time stamp conventional AP MAC layer. This reduces the processing delay (that is, it reduces the access delay on the AP). Similarly, the STA clock is read on the PHY layer of STA, more properly than on the MC layer, when the packet is received by the PHY layer of SAT. Additionally, the SAT clock is updated as needed based on the time stamp of the received package. This further reduces the processing delay (that is, it reduces the reception delay at the STA).
    BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a block diagram of a wireless communication system implementing time synchronization, according to an embodiment of the invention. Figure 2 shows a block diagram of a 20 layer of physical communication (PHY) and layer of z communication of access control to the medium (MAC) in a wireless station that implements clock synchronization in a wireless communication system comprising a wireless local area network, according to the modalities of the present invention. Figure 3A shows a timing diagram
    ] example and process flow in which an access point 'transmits a synchronization packet comprising a signaling frame including a time stamp to a receiving station on a wireless local area network (WLAN), in accordance with a modality of invention.
    Figure 3B shows a flow chart of a time synchronization process according to an embodiment of the present invention.
    Figure 4 shows a block diagram of a wireless local area network comprising a wireless transmitter station and a wireless receiver station, implementing time synchronization, according to an embodiment of the invention.
    Figure 5 shows an exemplary process and timing diagram for the interactions between PHY (PLCP) convergence procedure sublayer and MAC layer, and additionally between PHY PLCP sublayer and PHY-dependent physical layer (PMD) sublayer PHY of the transmitting station in Figure 4 for the: 20 time synchronization, according to a mode of. invention.
    Figure 6 illustrates an exemplary process and timing diagram for the interactions between the MAC layer and the PHY PLCP sublayer, and also between the PHY PLCP sublayer and PHY PMD sublayer, of the receiving station PHY layer in Figure 4 for synchronization. according to an embodiment of the invention.
    7 Figure 7 illustrates a timing and process diagram, exemplary for interactions between the MAC layer and the PHLC PLCP sublayer, and also between the PHY PLCP sublayer and the PHY PMD sublayer, of the transmitting station's PHY layer in Figure 4 for time synchronization, according to an embodiment of the invention.
    BEST MODE FOR CARRYING OUT THE INVENTION Modalities of the present invention provide a method and system for high accuracy clock synchronization protocol for communication between devices in a communication system such as a wireless communication system comprising a wireless network. Modalities of the invention provide exact clock synchronization through the interaction between communication layers and sublayers for wireless communication networks.
    In one embodiment, the present invention provides a process for time synchronization in a wireless communication system, comprising transmitting a '20 synchronization frame from a wireless transmitter 2 to a wireless receiver via a communication medium. wireless, wherein the sync frame includes a time stamp comprising a transmission time indicating the local transmitter time when a symbol at a predefined position on the sync frame is placed on the wireless communication medium for transmission.
    The process further includes receiving the To sync frame on a physical layer of the receiver, and determining a reception time comprising the local time of the receiver when the sync frame symbol was received from the wireless media on the physical layer. receiver.
    The process also includes the provision of the received synchronization frame for an upper communication layer at the receiver, where the synchronization frame reaches the upper communication layer at an arrival time indicating a local time of the receiver at which the Synchronization frame arrives to the top layer.
    The process also includes the time synchronization of the receiver with the transmitter by determining a difference between the time stamp and the reception time, and the adjustment of the local time of the receiver with the difference to synchronize the receiver with the transmitter in time.
    These and other features, aspects and advantages of the present invention will become understood with reference to the following description, appended claims and
    : 20 attached figures. 2 MODE FOR THE INVENTION
    The present invention provides a highly accurate clock synchronization protocol for communication between devices in a communication system such as a wireless communication system comprising a wireless network.
    Modalities of the invention provide
    'exact clock synchronization through the interaction between' the communication layers and sublayers for wireless communication networks,
    Figure 1 shows a block diagram of an exemplary wireless local area network 100 (such as WLAN according to IEEE 802.11 standards), comprising multiple wireless stations including an AP 102 that functions as a coordinator, and other stations ( STAs) 104 such as STA: ..., STA, wherein network 100 is optimized to implement time synchronization in accordance with an embodiment of the present invention, as described herein.
    Wireless stations perform wireless communication through a communication link such as a wireless communication medium (for example, radio frequency (RF) channel). The network 100 implements exact clock synchronization between a plurality of wireless stations through the interaction between the communication layers and sublayers for wireless communication, according to an embodiment of the invention.
    According to a modality of the invention, AP 102 Es 20 and STAS 104 implement a frame structure for. data transmission between them, using packet transmission through communication layers including a Data Link Layer comprising a MAC layer, and a PHY layer, as specified in the Open Systems Interconnection model (OST model). In a wireless station, the MAC layer receives
    'a data package including payload data, and attaches a MAC header to it, to build a MAC Protocol Data Unit (MPDU). The MAC header includes information such as a source address (SA) and a destination address (DA). The MPDU is a part of a PHY Service Data Unit (PSDU) and is transferred to a PHY layer on the wireless station such as the AP to attach a PHY header (ie, a PHY preamble) to it to build a Unit of PHY Protocol Data (PPDU). The PHY header includes parameters for determining a transmission scheme including an encoding / modulation scheme. Before transmission as a packet from the AP to a STA, a preamble is attached to the PPDU, which includes synchronization information and channel estimation.
    Figure 2 shows an exemplary block diagram of a PHY 110 layer and a MAC 111 layer in a wireless station that implements clock synchronization using a synchronization management module 112, in accordance with the modalities of the present invention. The PHY layer. includes a PLCP 110A sublayer, and a PMD 110B sublayer.
    In one implementation, the invention allows the determination or estimation of the delay in different communication layers (for example, MAC 111 layer, PHY 110 layer), and also the delay due to information passing between the communication layers, in a wireless station . Per
    For example, an implementation of the invention provides synchronization: high accuracy time in MAC / PHY layers by focusing on cross layer / sublayer interactions! as further described below.
    According to an embodiment of the invention, time synchronization is achieved using the synchronization signals (such as transmission beacons) over a wireless channel, directly at the PHY / MAC layers of a wireless transmission station (for example, an AP 102) and a receiving station (for example, an STA 104) on a wireless local area network, to minimize the instability of synchronization delay. When a receiving station receives a time signal from a transmitting station, The synchronization management module 112 of the receiving station adjusts the time stamp value based on the delay time in the PHY 110 layer and also the delay between the PHY layer 110 and the MAC layer 111 at the receiving station. Then, the receiving station can set its system clock (local z 20 time) to the set time stamp value no. flag to synchronize with the transmitting station's system clock (for example, the AP).
    Parameters related to timing are passed between communication layers or sublayers to support exact time synchronization according to the modalities of the invention. The invention also provides mechanisms for passing parameters related to timing between the 'MAC 111 layer and the PLCP 110A sublayer, and also between the PLCP 110A sublayer and the PMD 110B sublayer. As such, the invention allows recording of time in communication layers / sublayers and passing parameters between communication layers and sublayers.
    Figure 3A illustrates an exemplary timing and process flow diagram 20, in which the AP transmits a synchronization packet comprising a signaling frame including a time stamp, to a receiving STA. The receiving STA adjusts the time frame value of the synchronization frame by adjusting a processing delay in the PHY layer of the receiving STA and also a passage delay between the PHY and MAC layers of the receiving STA when at least a portion of the received frame is processed and moves from the PHY layer to the MAC layer of the wireless station, The transmitting station has a system clock set to a local time, and the receiving station has an F 20 system clock set to a local time, where at 2 local time at the receiving station need not be initially synchronized with the local time at the transmitting station. An exemplary scenario and procedure for synchronizing local time at the receiving station with local time at the transmitting station is as follows, according to an embodiment of the present invention. The local time ta0 is the time when the entire packet is built on the transmitter station's MAC layer, which in this example is the AP. The time such is the time when the symbol at a predefined position of the packet is placed on the wireless channel by the PHY layer of the AP. The time ta3 'is the time when the symbol at the preset position of the packet is received from the wireless channel by the PHY layer of a receiving SPA. The time ta4 'is the time when the received packet passes through the PHY layer of the STA and reaches the MAC layer of the STA.
    As there is a clock deviation, the local time / clock readings are different on AP 102 and STA 104. At local time ta0O, the AP's MAC layer applies a signaling time stamp (ie Time Stamp) as time. location such as when a symbol at a predefined position on the signaling board will be placed on the wireless channel via the PHY layer of the AP. In one embodiment, the time stamp (tal) comprises an estimated local time when a signboard symbol at a predefined position on the signboard will be placed on the wireless channel z 20 through the PHY layer of the AP (for example, : average delay duration between ta0 and such). In another embodiment, the timing (such) is determined based on the timing primitives, as further described below in relation to Figures 5-7. Propagation delay is the propagation time of a bit in the wireless channel (for example, a radio frequency transmission channel), in the transmission of a packet (for example, beacon) from the AP to the STA. Propagation delay is generally negligible in relation to a flag interval, and is a function of the physical distance between the STA and the AP. Thus, the propagation delay varies for different STAS that are at different distances from the AP. However, when the positions of the STAs in relation to the AP are fixed, the corresponding propagation delays are constant values. The propagation delay is small and relatively easy to calculate compared to the processing delay. For example, If the distance between an AP and a STA is less than 100 meters, the propagation delay is less than 100 / (3 * 10º) = 333.3 ns. In an example where flags are used as sync packets, The flag range indicates the range between sync packets.
    The processing delay includes the processing delay at the AP (i.e., access delay) and the processing delay is 20 at the STA (i.e., reception delay). O . processing delay in the AP comprises the time for | a bit passes from an AP MAC layer through the AP PHY layer to the wireless channel. Thus, to minimize processing delay on the AP, the packet time stamp should be as close to the time as possible when the symbol in the preset position is placed on the wireless channel.
    ] The processing delay at STA comprises the time required for the symbol at the predefined position in a packet received from the wireless channel, to be processed at the PHY layer of STA, reaching the MAC layer of i STA.
    In the example shown in Figure 3A, The processing delay at STA comprises the difference between ta3 'and ta4'. Thus, in order to minimize the processing delay in the STA, the time ta 'in the MAC layer of STA must be as close as possible to the time ta3' when the symbol in the preset position is received in the PHY layer of STA from the wireless channel.
    At the receiving STA, the PHY layer receives the signaling packet at the local time ta3 'at which the PHY layer reports the reception time ta3' to the MAC layer at the receiving STA.
    At local time ta4 'the MAC layer of the receiving STA receives the synchronization packet from the PHY layer of the receiving station (that is, the MAC layer of STA receives the symbol in the preset position of the received frame, from the PHY layer of STA at time ta4 '. E 20 The STA - receiving synchronization management module then determines a difference between the signaling time stamp and ta3i, where: = Time stamp - ta3. The difference (a signed number) is then added to taá local time to determine an adjusted local time S as:
    S = such +.
    'The system clock at the receiving station representing the local time is set to the set local time A. As such, theThe system clock at the receiving station is synchronized with The system clock at the transmitting station.
    With reference to the flowchart in Figure 3B, an implementation of a highly accurate time synchronization process 300 according to an embodiment of the present invention comprises the following process blocks: Block 301: The MAC layer of AP generates a synchronization package comprising a signal board, and applies the signal board time stamp indicating a local AP time for transmission time (for example, such) when a symbol at a predefined position on the signal board will be placed on the wireless channel via the PHY layer of the AP.
    Block 302: The PHY layer of AP begins transmitting E 20 of the beacon on the wireless channel. "Block 303: The PHY layer of STA begins receiving the signaling frame on the wireless channel from the AP.
    Block 304: The STA PHY layer reads the local STA clock / time to receive the time (for example, ta3 ') when the symbol at the signal board's predefined position reaches the STA PHY layer.
    Block 305: The STA PHY layer informs the reception time to the STA MAC layer and passes the signaling frame to the STA MAC layer.
    Block 306: The STA MAC layer receives the signaling frame from the STA PHY layer, where the signaling frame arrives at the STA MAC layer at the local arrival time of STA (e.g., ta4 ').
    Block 307: The MAC layer of STA determines the difference (for example,) between the marking and signaling frame time and the reception time (for example, ta3 ').
    Block 308: The STA MAC layer adds the difference (a signed number) to the arrival time (for example, tas') to determine a revised local time.
    Block 309: The STA clock is set to the revised local time, such that the STA clock is synchronized with the AP clock.
    If the distance between the AP and the STA can be estimated to determine the propagation delay, the STA can additionally adjust its clock (time recorder) z 20 by subtracting the propagation delay from: the revised local time.
    An exemplary application of a mode of the synchronization process described above is described here, below, for wireless millimeter wave communication standards such as the IEEE 802.11ad specification over the 60 GHz frequency range, and specification of
    Wireless Gigabit Alliance (WiGig). WiGig applies to |
    'multi-gigabit speed wireless communication technology operating over the 60 GHz radio frequency range.
    WiGig is an effort by the industry to define a digital wireless network interface specification for wireless signal transmission in the 60 GHz and higher frequency range for wireless local area networks and wireless local area network devices such as consumer electronics (CE) and other electronic devices including wireless radios.
    According to the IEEE 802.11 family of protocol specifications, the MAC layer provides the primitives and an interface for an upper layer to perform timing calculations.
    This is done by indicating the occurrence of the end of the last symbol of a data frame, specific to the upper layer, in which the upper layer registers a time stamp and sends the time stamp through the upper layer data packets.
    Modalities of the invention provide improvements to the $ 20 IEEE 802.11 protocol specification (such as the standard: IEEE 802.11ad), where such improvements described herein in relation to the modalities of the invention, include processes and architectures for time synchronization between a transmitting station and a receiving station such that artifacts such as delay instability caused by the interaction between the upper layer and the MAC layer, and between the MAC layer and the PHY layer, are minimized. l 'Figure 4 shows an exemplary block diagram of:
    a wireless local area network 200 comprising a wireless transmitter station 201 and a wireless receiver station 210, according to an embodiment of the invention.
    Each of stations 201 and 210 is an exemplary implementation of the wireless station illustrated in Figure 2 and described above, according to an embodiment of the invention.
    As shown in Figure 4, the transmitting station 201 includes a PHY 202 layer, and a MAC 203 layer. The transmitting station 201 implements clock synchronization using a MAC 204 synchronization manager module and a PHY 205 synchronization manager module, configured to operate in data / synchronization packets 206 (including timing / synchronization information), according to the modalities of the present invention.
    Receiving station 210 includes a PHY 212 layer, and a MAC 213 layer. Receiving station 210 provides clock synchronization using an IS 20 synchronization MAC 214 management module and a PHY 215 synchronization management module, configured to operate on data / synchronization 216, according to the modalities of the present invention.
    The data / synchronization packets 216 comprise data / synchronization packets 206, received from the transmitting station 201. In one implementation, network 200 implements a
    | wireless communication protocol based on IEEE '802.11 standards, and additionally provides time synchronization using a Time Synchronization Function (TSF), according to an embodiment of the invention. The MAC layer 203 of the transmitting station 201 includes a MAC synchronization manager module 204, and the PAY 205 layer includes a PHY 205 synchronization manager module, according to an embodiment of the invention. the MAC 204 synchronization manager module determines the current clock reading time when information at a predefined position of a 206 packet (for example, a flag or other frame) is transmitted by the PMD 110B sublayer (Figure 2) of the PHY 202 layer of the transmitting station 201 when detected by the PHY 205 synchronization manager module. The MAC layer 213 of the receiving station 210 includes a MAC 214 synchronization manager module, and the PHY 212 layer includes a PHY 215 synchronization manager module, according to a invention. The MAC 214 synchronization manager module determines the time of z 20 real clock reading when a predefined position of a packet 216 (for example, a flag or other frame) is received by the sub-layer PMD 110B of the PHY 212 layer as detected by the module synchronization manager PHY 215.
    In one embodiment of the invention, the position | The preset value is set to the preamble start point of a package / frame.
    Figure 5 shows a diagram of S timing and exemplary process 30 for the interactions between the MAC layer and the PLCP PHY sublayer, and additionally between the PLCP PHY sublayer and the PMD PHY sublayer, of the PHY 202 layer at the transmitting station 201 (for example, AP 102 | in Figure 1) for frame communication (packet), according to an embodiment of the invention.
    Figure 6 illustrates an exemplary timing and process diagram 40 for the interactions between the MAC layer and the PLCP PHY sublayer, and also between the PLCP PHY sublayer and PMD PHY sublayer, of layer 212 at the receiving station 210 (for example, a STA 104 in Figure 1) for frame communication (packet), according to an embodiment of the invention.
    An exemplary operating scenario according to an embodiment of the invention is described below in conjunction with Figures 4-6. The MAC 204 synchronization manager module of the transmission station 201 (Figure 5) determines the effective clock reading as the time stamp (such) when the symbol in the predefined position is transmitted on the channel without 20 wire, via a TIME OF DEPARTURE parameter within the 2 TXSTATUS vector after the PLCP 110A sublayer emits the primitive PHY TXSTART.confirmation (TXSTATUS) (ie PHY- TXSTART.confirmation for the MAC 203 layer. The TIME OF DEPARTURE parameter loads The time value for the preamble start point, to be transmitted in the PMD sub layer 110B of the PHY 202 layer of the wireless transmitter station
    '201. The TXSTATUS vector represents a list of parameters | 'that the PHY layer provides for the MAC layer related to the transmission of an MPDU. This TXSTATUS vector contains PLCP operating parameters and PHY operating parameters. PHY TXSTART.confirmation is a service primitive transmitted to the MAC layer via the PHY layer to initiate an MPDU transmission.
    C-PSDU indicates an encoded PSDU. Typically, the most secure coding / modulation scheme is applied to a PHY signal field in the PHY header, and an additional cyclic redundancy check (CRC) is added to ensure that this information is received correctly at the receiver. The MAC header and payload data are normally treated equally and transmitted using the same coding / modulation scheme that is less robust than that for the PHY signal field of the PHY header. The MAC 214 synchronization manager module of the MAC layer 213 of the receiving station 210 (Figure 6) obtains the estimated time when the transmitted frame preamble $ 20 began to be received in the PHY 212 layer of the receiving station 210 using the parameter RX START OF FRAME OFFSET within RXVECTOR after the PHY 212 layer PLCP sublayer emits the PHY primitive RXSTART.indication (RXVECTOR) (ie PHY-RXSTART, .Ind) 1 25 for the MAC 213 layer.
    | The RX START OF FRAME OFFSET parameter loads The estimated temporal displacement (in units of 10 'nanoseconds) from the moment when the beginning of the preamble corresponding to the arrival frame (packet)' reaches the PHY layer of the receiving station 210 (for antenna port), until the time when the PHY RXSTART.indication primitive is issued for the MAC 213 layer.
    Therefore, the time when the MAC layer of receiver 213 obtains the primitive PHY RXSTART.indication (RXVECTOR) minus RX START OF FRAME OFFSET, provides the estimated time of receipt of the preamble start at the receiving station
    210.
    PHY RXSTART.indication is an indication by the PHY layer for the MAC layer that the PLCP has received a valid start frame delimiter (SFD) and PLCP header. The primitive provides PHY RXSTART.indication (RXVECTOR). The RXVECTOR vector represents a list of parameters that the PHY layer provides to the MAC layer from the receipt of a valid PLCP header or from the receipt of the last bit of PSDU data in the received frame. The RXVECTOR: 20 vector contains both MAC and MAC management parameters.
    s In an exemplary implementation for a millimeter-wave wireless communication pattern (mm or mmiWave), a synchronization mechanism according to one embodiment of the invention is as follows. The transmitting station 201 transmits an mmHWave packet such as a Signal board, or an Announcement board, applies the!
    | frame time stamp field so that it is' equal to the value of the transmitter TSF time recorder in the temporal transmission of the frame preamble from the PHY layer 202 of the wireless station 201 to the start of the wireless channel. The frame time stamp value includes any transmitting station delays while at least part of the frame travels through the local PHY layer of station 202 from the MAC-PHY interface to the interface with the wireless channel, at transmitting station 201.
    At the wireless receiver station 210, operating in the mmWave range, the time frame value of the received frame is obtained and adjusted by adding an amount equal to the delay at the receiving station 210 when at least a portion of the received frame moves through the layer Local PHY 212 plus the time since the preamble started to be received in the PHY 212 layer as estimated by RX START OF FRAME OFFSET. According to another embodiment of the invention, the z 20 predefined position in a frame transmitted from the transmitting station 201 to the receiving station 210 is adjusted to the starting point of the PLCP header. The MAC 204 synchronization manager mode of the MAC 203 layer of the transmitting station 201 obtains the actual clock reading time since the PHY TXSTART.confirmation (ie PHY-TXSTART. Confirm) is issued to the MAC layer 203 at the beginning of the PLCP header.
    ] At the receiving station 210, PMD DATA.ind (ie PM DATA. Indication) is dispatched from the PMD sublayer to the PHY 212 layer PLCP sublayer, at the beginning of the PLCP header, where the PHY 215 synchronization manager module of the PLCP sublayer of the receiving station 210 determines when the beginning of the PLCP header is received in the PMD sublayer of the PHY 212 layer. The PHY RXSTART.indication (RXVECTOR) is sent to the MAC layer 213 at the end of the PLCPheader.PMD DATA.ind informing the PLCP that a Preamble is successfully detected in the PMD sublayer and the data (PLCP header) will start to pass from the PMD sublayer to the PLCP sublayer.
    According to one aspect of the invention, an RX START TIME OF PLCP HEADER parameter is added to the RXVECTOR to record the time when the PMD DATA.ind is issued to the PHY 212 layer PLCP sublayer of the receiving station 210. The RX START TIME parameter OF PLCP HEADER loads the time value indicating the time when the start of the PLCP header is It is received at the PMD sublayer of the PHY 212 layer of the station: receiver 210.
    According to another embodiment of the invention, for a millimeter wave wireless communication standard, using a synchronization mechanism according to one embodiment of the invention, the wireless transmitter station 201 transmitting an mmWave packet such as a frame of
    23 | Flag, or an Announcement board, adjusts the value of the frame time stamp field so that it is equal to the value of the transmitter TSF time register at the time the transmission of the first data symbol of the PLCP header of the frame for The wireless channel is started.
    The time stamp value includes any transmitting station delays while at least a portion of the frame moves through the local PHY layer of station 202 from the MAC-PHY interface to its interface with the wireless channel, at transmitting station 201. In the wireless receiver station 210, operating in the mmWave range, the time frame value of the received frame is obtained and adjusted by adding an amount equal to the delay of the receiving station through at least a portion of the received frame when traversing the PHY layer location 212 plus the time since the first PLCP header data symbol was received in the PHY 212 layer as indicated by RX START TIME OF PLCP HEADER.
    With reference to the timing diagram e: 20 exemplary process 50 in the transmitting station 201 in Figure s 7, according to another embodiment of the invention, the predefined position in a frame transmitted from the transmitting station 201 to the receiving station 210 is adjusted to the end point of the PLCP header of a packet / frame.
    Specifically, Figure 7 shows an exemplary interaction between the MAC-PLCP-PMD layers / sublayers at the transmitting station 201 based on the primitive: PHY TXPLCPEND.indication provided according to an embodiment of the invention.
    The primitive PHY TXPLCPEND.indication (ie PHY-TXPLCPEND.indication) comprises signaling for the transmitter MAC layer, informing that the transmission of the PLCP header on the wireless channel is complete, at which the MAC layer can record the time when PHY TXPLCPEND. indication is obtained as a time stamp (such), according to an embodiment of the invention.
    At the transmitting station 201, this makes it possible to obtain the time directly using the primitive PHY TXPLCPEND.indication that is sent to the MAC layer 203 when the transmission of the PLCP header is completed at the PHY layer 202. The MAC layer 203 of the transmitting station 201 obtains the clock (local time) when the PLCP header transmission is completed in the PHY 202 layer, by recording the time when the PHY TXPLCPEND.indication primitive is received from the sublayer 20 PLCP of layer PHY 202. At receiving station 210, layer s MAC 213 obtains the actual local time (ta3 ') based on PHY RXSTART.indication, where PHY RXSTART.indication is output to MAC layer 213 at the end of the PLCP header (Figure 6). According to an embodiment of the invention, to define PHY TXPLCPEND.indication, the following conditions
    (improvements) in Table 1 are provided for | 'TIEEE 802.11 specification, "Standard for Information technology-Telecommunications and information exchange between systems-Local and metropolitan area networks Specific requirements, Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications", IEEE Computer Society , June 12, 2007: Table 1 PHY-TXPLCPEND. indication Function - this primitive indicates the completion of transmission from the PLCP header to the local MAC entity.
    Service primitive semantics - the primitive semantics is as follows: PHY-TXPLCPEND, indication This primitive has no parameters.
    When generated - PHY-TXPLCPEND.indication is generated by a transmitter PHY entity to indicate the completion of the transmission of the PLCP header to the local Ú IMAC entity. = Effect of receipt - the receipt of this primitive by the MAC entity will cause the MAC to register at the time when) this primitive is received only if TIME OF DEPARTURE REQUESTED is true in the corresponding PHY TXSTART.request.
    ] According to an embodiment of the invention, the transmitting station 201 transmitting an mmWave frame such as a Beacon frame or an Announcement frame, sets the frame time field value so that it is equal to the frame value. transmitter TSF time recorder when the transmission of the data symbol containing the first bit of the MPDU through the endless channel begins.
    The time stamp value includes any transmitting station delays while at least a portion of the frame travels through local PHY 202 from the MAC-PHY layered interface to the wireless channel interface at transmitting station 201. When operating in the mmW range, at the receiving station 210, the mark value and time of the received frame is obtained and adjusted by adding an amount equal to the delay through the local PHY layer 212 of the receiving station 210 plus the time since the receipt of the last PLCP header data symbol of the received frame was completed as indicated by 7 20 PHY RXSTART.indication at receiving station 210. Ss The exemplary synchronization process in Figure 3A applies to the processes in relation to Figures 5-7, however, the value Time marking (tl) is determined based on the timing primitives in relation to Figures 5-7, more properly than the estimation in relation to Figure 3A.
    Specifically, ta0 is the time when the symbol at the predefined position in the frame is on the MAC layer of 'transmitter, such is the time when that symbol is placed on the wireless channel by the transmitter, ta3' is the time value when that symbol is received on the wireless channel through the receiver PHY layer, ta4 'is the time when the receiver starts setting the local clock after receiving the symbol (ie, beacon frame or other synchronization frames that carries time synchronization information such as marking information of time). The receiver adjusts its local clock value by adding it (where = tal-ta3 '). The time stamp includes such value. Although certain modalities are described for the AP and an STA, modalities of the invention are also applicable to synchronization between any two neighboring STAs. Thus, according to the present invention, to obtain superior time synchronization accuracy between the AP and the STAs, the local clock time is read as close to the event trigger point as possible, which means that 7 20 o Local clock time is read in the PHY layer to minimize propagation and processing delay.
    According to the modalities of the present invention, when a packet is created by the MAC layer in the AP, the packet receives the time stamp of the clock when the packet reaches the PHY layer of AP for transmission through the channel, more properly than conventional timekeeping in the AP MAC layer. This reduces the processing delay (that is, it reduces the access delay on the AP). Similarly, the STA clock is read in the PHY layer of STA, more properly than in the MAC layer, when the packet is received by the PHY layer of STA. In addition, the STA clock is updated as needed based on the received packet time stamp. This further reduces the processing delay (that is, it reduces the reception delay at the STA).
    As is known to those skilled in the art, the above mentioned exemplary modalities can be implemented in many ways, such as program instructions for execution by a processor, such as software modules, microcode, a computer program product in readable media by computer, as logic circuits, as integrated circuits of specific application, as firmware, as consumer electronic devices, etc., in wireless devices, in wireless transmitters / receivers, in wireless networks, etc.
    7 20 In addition, the modalities can take the form of an entirely hardware modality, an entirely software modality or a modality containing both hardware and software elements. Modalities of the present invention have been described with reference to flowchart illustrations and / or block diagrams of methods, equipment (systems) and computer program products according to the modalities of the invention.
    Each 'block of such illustrations / diagrams, or combinations thereof, can be implemented by computer program instructions.
    Computer program instructions when provided to a processor produce a machine, such that instructions, which they execute through the processor, create means to implement the functions / operations specified in the flowchart and / or block diagram.
    Each block in the flowchart / block diagrams can represent a hardware and / or software module or logic, implementing “modalities of the present invention.
    In alternative implementations, the functions marked in the blocks can occur outside the order shown in the figures,
    simultaneously, etc.
    The terms: "computer program medium", "computer usable medium", "computer readable medium" and "computer program product", are used in general referring to media such as main memory, secondary memory, memory unit removable storage, a 7 20 hard drive installed in the hard drive, es signs.
    These computer program products are means for providing software to the computer system.
    The computer-readable medium allows the computer system to read data, instructions, messages or message boards, and other computer-readable information from the computer-readable medium.
    The medium readable by
    ] computer, for example, may include non-volatile memory, 'such as a floppy disk, ROM, flash memory, disk drive memory, a CD-ROM, and other permanent storage medium.
    It is useful, for example, to transport information, such as computer data and instructions, between computer systems.
    In addition, the computer-readable medium may comprise computer-readable information in a transient state medium such as a network link and / or a network interface, including a wired network or a wireless network, which allows a computer to read such computer-readable information.
    Computer programs (also called computer control logic) are stored in main memory and / or secondary memory.
    Computer programs can also be received via a communication interface.
    Such computer programs, when executed, enable the Computer System to carry out the characteristics of the modalities, as discussed here.
    In particular, computer programs, z 20 when executed, enable the multi-core processor to realize the resources of the computer system.
    Consequently, such computer programs represent controllers of the computer system.
    Although the present invention has been described with reference to certain versions of it; however, other versions are possible.
    Therefore, the essence and scope of the appended claims should not be limited to the description of the preferred versions contained herein.
    权利要求:
    Claims (15)
    [1]
    1. TEMPORAL SYNCHRONIZATION METHOD IN A WIRELESS COMMUNICATION SYSTEM, characterized by understanding: transmitting a synchronization frame from a wireless transmitter to a wireless receiver through a wireless communication medium, in which the synchronization frame includes a time stamp comprising a transmission time indicating the local time of the transmitter when a symbol at a predefined position on the synchronization board is placed on the wireless communication medium for transmission; receiving the synchronization frame of a physical layer from the receiver; determining a reception time comprising the receiver's local time when the sync frame symbol was received from the wireless communication medium on the receiver's physical layer; time synchronize the receiver with the transmitter by: determining a difference between the time stamp and the receiving time; and adjusting the receiver's local time based on the difference to time synchronize the receiver with the transmitter.
    [2]
    2. Method according to claim 1, characterized by further comprising:
    ! 2 providing the received synchronization frame to an upper communication layer at the receiver, where the synchronization frame reaches the upper communication layer at an arrival time indicating a local time of the receiver at which the synchronization frame reached the upper layer; wherein the time synchronization of the receiver with the transmitter comprises: using the time stamp of the received synchronization frame to determine a difference between the time stamp and the time of receipt; determine the revised local time based on a combination of the arrival time and the difference; and update the receiver's local time based on local time | revised to temporarily synchronize the receiver with the transmitter.
    [3]
    Method according to claim 1, further comprising: reading a local transmitter clock to obtain the local time when a symbol at a predefined position in the synchronization package is placed on the wireless communication medium for transmission to the receiver; and reading the receiver's local clock to obtain the local time when a symbol at a predefined position in the synchronization packet is received in the wireless communication medium from the transmitter.
    [4]
    4. Method according to claim 1,
    characterized in that the time synchronization of the receiver with the transmitter comprises: adjusting the local time of the receiver by adding a processing delay in the physical layer of the receiver and a processing delay between the physical layer and the upper communication layer.
    [5]
    5. Method according to claim 1, characterized in that: the time stamp comprises a transmission time estimating the local time of the transmitter when a symbol in a predefined position of the synchronization frame is placed in the wireless communication medium for the streaming.
    [6]
    6. Method according to claim 1, characterized in that: the time stamp comprises a local time of the transmitter when a symbol in a predefined position of the synchronization board is placed on the wireless communication medium for the transmission.
    [7]
    Method according to claim 1, characterized in that: the wireless communication system comprises a wireless local area network; the transmitter comprises a layer of access control to the medium (MAC) and a physical layer (PHY) for wireless communication; and the receiver comprises a MAC layer and a PHY layer for wireless communication, the upper communication layer of the receiver comprises the MAC layer.
    [8]
    Method according to claim 7, characterized by: | the preset position will be adjusted to the start point of the preamble of the sync frame.
    [9]
    Method according to claim 7, characterized in that the predefined position is set to The start point of the PLCP header of the synchronization frame.
    [10]
    Method according to claim 7, characterized in that the predefined position is set to The end point of the PLCP header of the synchronization frame.
    [11]
    11. WIRELESS RECEIVER, characterized by comprising: a physical layer (PHY) arranged for wireless communication, including receiving a synchronization frame from a wireless transmitter through a wireless communication medium, the synchronization frame including a time marking comprising a transmission time indicating the local time of the transmitter when a symbol at a predefined position in the synchronization frame is placed on the wireless communication medium for transmission to the receiver; and a synchronization module configured to determine the reception time comprising the local time of the receiver when the symbol of the synchronization frame was received from the wireless communication medium on the physical layer of the receiver, and to provide the received synchronization frame to an upper communication layer at the receiver, in which the synchronization frame reaches the upper communication layer at an arrival time indicating the local time of the receiver at which the synchronization frame reaches the upper layer; the receiver synchronization module being operable to temporally synchronize the receiver with the transmitter by: determining a difference between the time stamp and the receiving time; and adjusting the local time of the receiver with the difference to synchronize the receiver with the transmitter in time.
    [12]
    Wireless receiver, according to claim 11, characterized in that the receiver's synchronization module is operable to temporally synchronize the receiver as (transmitter: using the synchronization frame time stamp received to determine a difference between timing and receiving time; determining a revised local time based on a combination of the arrival time and the difference; and updating the receiver's local time based on the revised local time to temporally synchronize the receiver with the transmitter.
    [13]
    Wireless receiver according to claim 11, characterized in that: the receiver's synchronization module is operable to read a local receiver clock to obtain the local time. when a symbol at a predefined position in the synchronization packet is received in the wireless medium from the transmitter.
    [14]
    Wireless receiver according to claim 11, characterized in that the receiver's synchronization module adjusts the receiver's local time by adjusting a processing delay in the physical layer of the receiver and a processing delay between the physical layer and the upper communication layer.
    [15]
    15. Wireless receiver according to claim 11, characterized in that the time stamp comprises a transmission time estimating the local time of the transmitter when a symbol in a predefined position of the synchronization frame is placed in the wireless communication medium. transmission.
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    同族专利:
    公开号 | 公开日
    AU2011221736A1|2012-09-20|
    RU2536178C2|2014-12-20|
    CN102783078A|2012-11-14|
    EP2532114A4|2016-04-13|
    CA2791698A1|2011-09-09|
    EP2532114A2|2012-12-12|
    CA2791698C|2017-07-25|
    US20110216747A1|2011-09-08|
    JP2013521692A|2013-06-10|
    KR20130048124A|2013-05-09|
    MX2012010044A|2012-10-01|
    CN102783078B|2016-11-23|
    WO2011108870A2|2011-09-09|
    AU2011221736B2|2015-01-15|
    JP2016067025A|2016-04-28|
    JP6130471B2|2017-05-17|
    KR101849243B1|2018-04-16|
    RU2012137780A|2014-03-10|
    MY165237A|2018-03-14|
    JP5912086B2|2016-04-27|
    US9392565B2|2016-07-12|
    WO2011108870A3|2011-12-29|
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    法律状态:
    2020-09-08| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|
    2020-09-08| B15K| Others concerning applications: alteration of classification|Free format text: AS CLASSIFICACOES ANTERIORES ERAM: H04L 7/00 , H04W 56/00 , H04W 84/12 Ipc: H04W 56/00 (2009.01), H04J 3/06 (2006.01) |
    2021-01-19| B06G| Technical and formal requirements: other requirements [chapter 6.7 patent gazette]|
    2021-11-23| B350| Update of information on the portal [chapter 15.35 patent gazette]|
    2021-11-30| B07A| Application suspended after technical examination (opinion) [chapter 7.1 patent gazette]|
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