WO2016082230A1 - 一种虚拟载波侦听方法及装置 - Google Patents
一种虚拟载波侦听方法及装置 Download PDFInfo
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- WO2016082230A1 WO2016082230A1 PCT/CN2014/092624 CN2014092624W WO2016082230A1 WO 2016082230 A1 WO2016082230 A1 WO 2016082230A1 CN 2014092624 W CN2014092624 W CN 2014092624W WO 2016082230 A1 WO2016082230 A1 WO 2016082230A1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L9/00—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
- H04L9/40—Network security protocols
Definitions
- the present invention relates to the field of communications technologies, and in particular, to a virtual carrier sensing method and apparatus.
- VCS Virtual Carrier Sense
- IEEE Institute of Electrical and Electronics Engineers
- data is transmitted in the form of a transmission frame including a physical header and data, and the data includes a SERVICE field and a Physical Layer Convergence Procedure Service Data Unit (PSDU).
- PSDU is Media Access Control (MAC) layer data, including a MAC frame header, a frame body, and a Frame Check Sequence (FCS).
- FCS Frame Check Sequence
- the MAC frame header includes a duration field for indicating an expected remaining time for transmitting data including the transmission frame between the source wireless device and the destination wireless device.
- a common virtual carrier sensing method is: when a transmission frame is transmitted by a source wireless device to a destination wireless device through a wireless channel, other wireless devices that use the same wireless channel with the two wireless devices may receive the transmission frame including All the contents are then determined by the FCS whether the transmission frame is a valid frame.
- a Network Allocation Vector (NAV) timer is set according to the duration field included in the transmission frame. Before the NAV timer is decremented to zero, these wireless devices cannot transmit data over the wireless channel even if they hear that the wireless channel is idle, to avoid interference with wireless devices transmitting data on the wireless channel.
- NAV Network Allocation Vector
- the devices when the transmission frame is an invalid frame, the devices cannot set the NAV timer according to the duration, and the data is transmitted on the wireless channel, so that multiple wireless devices simultaneously transmit data in the same wireless channel at the same time. , reducing the reliability of virtual carrier sensing.
- the embodiment of the invention discloses a virtual carrier sensing method and device for improving virtual carrier sensing reliability.
- a first aspect of the embodiments of the present invention discloses a virtual carrier sensing method, including:
- the transmission frame includes a service field and a duration field
- the service field includes a check field
- the check field carries a first check value
- the first check value is The second check value is obtained by being transmitted in the check field after being transmitted by using a wireless channel, where the second check value is calculated by a predetermined algorithm according to the field set when the wireless device that sends the transmission frame generates the transmission frame Obtained; wherein the field set is a partial field in a field included in the transmission frame, the field set includes the duration field; and the duration field includes a duration;
- the local time NAV timer is updated with the duration.
- the determining, according to the first check value, whether the duration is an effective duration includes :
- the duration is an effective duration.
- the transmission frame further includes receiving An address field
- the receiving address field includes a receiving address of the transmission frame
- the field set further includes the receiving address field
- updating the NAV timer of the local end by using the duration includes:
- the duration is determined to be a valid duration according to the first check value, and the receiving address is a valid receiving address, if the receiving address does not match the address of the local end, and the duration is greater than the NAV of the local end.
- the time of the timer using the duration to update the local NAV timer.
- the transmission frame further includes a physical header, where the physical header includes an indication Information, the indication information is used to indicate that the transmission frame includes the check field.
- a second aspect of the embodiments of the present invention discloses a virtual carrier sensing method, including:
- the transmission frame includes a service field and a duration field
- the service field includes a check field
- the check field carries a second check value
- the second check value is according to a field
- the set is calculated according to a predetermined algorithm, the field set is a partial field in a field included in the transmission frame, the field set includes the duration field, and the duration field includes a duration;
- Transmitting the transmission frame such that the wireless device receiving the transmission frame determines whether the duration is an effective duration according to a first check value, and when determining that the duration is an effective duration, utilizing Updating the network allocation vector timer of the wireless device, wherein the first check value is obtained after the second check value is carried in the check field and transmitted through a wireless channel.
- the transmission frame further includes a receiving address field, where the receiving address field includes a receiving address of the transmission frame.
- the set of fields further includes the receive address field.
- the transmission frame further includes a physical header, where the physical header includes an indication Information, the indication information is used to indicate that the transmission frame includes the check field.
- a third aspect of the embodiments of the present invention discloses a wireless device, including:
- a receiving unit configured to receive a transmission frame, where the transmission frame includes a service field and a duration field, where the service field includes a check field, where the check field carries a first check value, where the first
- the check value is obtained after the second check value is carried in the check field and transmitted by the wireless channel, where the second check value is a field according to the wireless device that sends the transmission frame to generate the transmission frame.
- the set is calculated according to a predetermined algorithm; wherein the field set is a partial field in a field included in the transmission frame, the field set includes the duration field; and the duration field includes a duration;
- a determining unit configured to determine, according to the first check value included in the transmission frame received by the receiving unit, whether the duration is a valid duration
- an updating unit configured to update the NAV timer of the wireless device by using the duration when the determining unit determines that the duration is an effective duration.
- the determining unit is specifically configured to:
- the duration is an effective duration.
- the transmission frame further includes receiving An address field
- the receiving address field includes a receiving address of the transmission frame
- the field set further includes the receiving address field
- the updating unit is configured to: when the duration is determined as the effective duration according to the first check value, and the receiving address is a valid receiving address, if the receiving address and the address of the wireless device are not Matching, and the duration is greater than the time of the wireless device's NAV timer, the NAV timer of the wireless device is updated with the duration.
- the transmission frame further includes a physical header, where the physical header includes an indication Information, the indication information is used to indicate that the transmission frame includes the check field.
- a fourth aspect of the embodiments of the present invention discloses a wireless device, including a processor, a memory, and an input device, where:
- the input device is configured to receive a transmission frame and send the data to the processor, where the transmission frame includes a service field and a duration field, where the service field includes a check field, where the check field carries a a check value, where the second check value is obtained by being transmitted in the check field after being transmitted through a wireless channel, and the second check value is a wireless sending the transmission frame
- the device generates the transmission frame according to a field set according to a predetermined set of algorithms; wherein the field set is a partial field in a field included in the transmission frame, and the field set includes the duration field;
- the time field includes the duration;
- the memory stores a set of program codes
- the processor is configured to call the program code stored in the memory to perform the following operations:
- the NAV timer of the wireless device is updated with the duration when the duration is determined to be an effective duration.
- the processor is configured to determine, according to the first check value, whether the duration is a valid duration.
- the way of time is as follows:
- the processor is configured to calculate, according to the set of fields, a third check value according to the predetermined algorithm
- the duration is an effective duration.
- the transmission frame further includes receiving An address field
- the receiving address field includes a receiving address of the transmission frame
- the field set further includes the receiving address field
- the processor is configured to: when the duration is determined to be a valid duration according to the first check value, and the receiving address is a valid receiving address, if the receiving address does not match an address of the wireless device, and The duration is greater than the time of the wireless device's NAV timer, and the wireless device's NAV timer is updated with the duration.
- the transmission frame further includes a physical header, where the physical header includes an indication Information, the indication information is used to indicate that the transmission frame includes the check field.
- a fifth aspect of the embodiments of the present invention discloses a wireless device, including:
- a generating unit configured to generate a transmission frame, where the transmission frame includes a service field and a duration field, where the service field includes a check field, where the check field carries a second check value, and the second
- the check value is calculated according to a field set according to a predetermined algorithm, the field set is a partial field in a field included in the transmission frame, the field set includes the duration field, and the duration field includes a duration;
- a sending unit configured to send a transmission frame generated by the generating unit, so that the target wireless device that receives the transmission frame determines, according to the first check value, whether the duration is a valid duration, and when determining the Updating the target wireless device with the duration when the duration is the effective duration
- a network allocation vector timer wherein the first check value is obtained after the second check value is carried in the check field and transmitted through a wireless channel.
- the transmission frame further includes a receiving address field, where the receiving address field includes a receiving address of the transmission frame.
- the set of fields further includes the receive address field.
- the transmission frame further includes a physical header, where the physical header includes an indication Information, the indication information is used to indicate that the transmission frame includes the check field.
- a sixth aspect of the embodiments of the present invention discloses a wireless device, including a processor, a memory, and an output device, where:
- the memory stores a set of program codes
- the processor is configured to call the program code stored in the memory to perform the following operations:
- the transmission frame includes a service field and a duration field
- the service field includes a check field
- the check field carries a second check value
- the second check value is according to a field
- the set is calculated according to a predetermined algorithm, the field set is a partial field in a field included in the transmission frame, the field set includes the duration field, and the duration field includes a duration;
- the output device is configured to send the transmission frame, so that the target wireless device that receives the transmission frame determines, according to the first check value, whether the duration is a valid duration, and when determining the duration Updating the network allocation vector timer of the target wireless device by using the duration, wherein the first check value is that the second check value is carried in the check field Obtained after the wireless channel is transmitted.
- the transmission frame further includes a receiving address field, where the receiving address field includes a receiving address of the transmitting frame
- the set of fields further includes the receive address field.
- the transmission frame further includes a physical header, where the physical header includes an indication Information, the indication information is used to indicate that the transmission frame includes the check field.
- the wireless device uses the duration only when the received transmission frame is a valid frame. Updating the local NAV timer; when the received transmission frame is an invalid frame, the wireless device cannot set the NAV timer according to the duration, and the data is sent on the wireless channel, so that multiple times appear in the same wireless channel at the same time.
- the wireless device transmits data at the same time, which reduces the reliability of virtual carrier sensing.
- the duration of the received transmission frame is determined according to the first check value carried in the check field by including a check field in the service field of the transport frame.
- the duration of the NAV timer can be updated by using the duration, so that the local end does not send data before the time of the NAV timer is reduced to zero, avoiding the same wireless at the same time. The situation in which multiple wireless devices simultaneously transmit data occurs in the channel, thereby improving the reliability of virtual carrier sensing.
- FIG. 1 is a flowchart of a virtual carrier sensing method according to an embodiment of the present invention
- FIG. 3 is a flowchart of another virtual carrier sensing method disclosed in an embodiment of the present invention.
- FIG. 4 is a flowchart of a MAC frame header compression method according to an embodiment of the present invention.
- FIG. 5 is a flowchart of another MAC frame header compression method according to an embodiment of the present invention.
- FIG. 6 is a structural diagram of a wireless device according to an embodiment of the present invention.
- FIG. 7 is a structural diagram of another wireless device according to an embodiment of the present invention.
- FIG. 8 is a structural diagram of still another wireless device according to an embodiment of the present invention.
- FIG. 9 is a structural diagram of still another wireless device according to an embodiment of the present invention.
- FIG. 10 is a structural diagram of still another wireless device according to an embodiment of the present invention.
- FIG. 11 is a structural diagram of still another wireless device according to an embodiment of the present invention.
- FIG. 12 is a structural diagram of still another wireless device according to an embodiment of the present invention.
- FIG. 13 is a structural diagram of still another wireless device according to an embodiment of the present invention.
- the embodiment of the invention discloses a virtual carrier sensing method and device for improving virtual carrier sensing reliability. The details are described below separately.
- the transmission of the transmission frame may be erroneous, resulting in the content of the transmission frame received by the receiving end being different from the content generated by the transmitting end.
- the transmitting end in order to enable the receiving end to know whether the received transmission frame is correct or not, the transmitting end adds additional parity data to the transmission frame, that is, inputs the content of the transmission frame into a predetermined verification algorithm to obtain a transmission check value. It is then carried in the Frame Check field in the transport frame. After receiving the transmission frame, the receiving end calculates the received frame by using the same check algorithm as the receiving end, and obtains the received check value, and then compares it with the transmitted check value obtained from the received transmission frame.
- the transmission frame content is received correctly, that is, the transmission frame is a valid frame; if it does not match, it indicates that the transmission frame content is in error during transmission, or the transmission check value transmission error occurs, that is, the transmission frame is invalid. Frame, at this time, the receiving end discards the transmission frame.
- Errors due to unreliable wireless channels may occur anywhere in the transmission frame.
- the duration field in the transmission frame may still be correct.
- the duration in the duration field can still be used to set Own NAV timer, but in the prior art, when an invalid transmission frame is received, the frame is discarded, and the information of the duration that is still valid in the invalid transmission frame is not utilized. Therefore, a mechanism is needed to enable the receiving end to determine whether the duration field in the transmission frame is erroneous even in the case of an overall transmission error of the received transmission frame.
- the frame check field is located at the end of the frame, when the device receives a transmission frame and determines that the frame does not need to receive itself according to the receiving address field in the frame header, it will directly discard it. The frame will not continue to receive subsequent portions of the transmission frame to save energy. In this case, the receiving device has no way to determine whether the duration field is received correctly or not. If it receives an error, use Setting a NAV timer can cause unpredictable problems. Therefore, in the case where the wireless device only receives the frame header, it is necessary to accurately determine whether the duration field is correctly received.
- the method enables the receiving wireless device to determine whether the duration field is correctly received if only part of the transmission frame is received, thereby enabling the NAV timer to be correctly set and saving energy; and at the same time, even after receiving an invalid transmission frame
- the receiving wireless device can also individually determine whether the duration field is received correctly, thereby using it to set the NAV timer.
- the method provided by the embodiments of the present invention enables the wireless device to obtain an effective duration in more cases, thereby making the virtual carrier sensing mechanism more effective.
- FIG. 1 is a flowchart of a virtual carrier sensing method according to an embodiment of the present invention.
- the virtual carrier sensing method shown in FIG. 1 is applicable to wireless devices such as mobile phones and tablet computers.
- the virtual carrier sensing method shown in FIG. 1 is described from the perspective of the receiving side.
- the virtual carrier sensing method may include the following steps.
- S101 Receive a transmission frame, where the transmission frame includes a service field and a duration field, where the service field includes a check field, the check field carries a first check value, and the first check value is carried by the second check value.
- the second check value is calculated by the predetermined algorithm according to the field set when the wireless device that sends the transmission frame generates the transmission frame; wherein the field set is in the field included in the transmission frame.
- the field set includes a duration field; the duration field includes the duration.
- the received transmission frame includes a physical header and data
- the data includes a service field, a PSDU, a tail (Tail), and a padding (Pad).
- the PSDU is MAC layer data
- the PSDU includes a MAC frame header, a frame body, and an FCS
- the MAC frame header includes a duration field
- the duration field includes a duration.
- the service field includes a check field, a scrambling code initial value (Scrambler Initialization), where the check field carries a first check value, and the first check value is a second check value carried in the check field.
- the second check value is calculated by the predetermined algorithm according to the field set when the wireless device that generates the transmission frame generates the transmission frame; wherein the field set is a part of the field included in the transmission frame, the field The set includes a duration field; the duration field includes the duration.
- the first check value and the second check value are Can be equal or not equal; when the verification field transmission error occurs during transmission, the two are not equal; when the verification field is transmitted correctly during transmission, the two are equal.
- the service field may carry the check value by using a basic method or an extended method.
- the basic method is as follows: the length of the service field is generally 16 bits, where 7 bits is the initial value of the scrambling code generator and cannot carry information. Therefore, the remaining 9 bits can be used to carry the check value.
- the 802.11ac standard has proposed to use 8 bits in the service field.
- the method of carrying the check value, but the check value is the check value of the VTH-SIG-B field in the physical header. Therefore, a similar method (that is, using some or all of the remaining 9 bits) can be used to carry the field.
- Set check value If the check value of the SIG field in the physical header needs to be carried, the field set will also include the SIG field in the physical header.
- the extension method further increases the check value length based on the basic method, specifically: implicitly carrying the initial state value of the scrambling code generator of the transmission frame source wireless device. Check the value to increase the length of the check value.
- the scrambling code generator initial value and initial state are two different concepts.
- the former is the name of a subfield in the SERVICE field, the length is 7bits, usually takes a fixed value, for example, the current 802.11 standard takes 7bits all 0 sequence; the latter is the initial value of the 7-bit shift register in the scrambling code generator, the length It is 7 bits, usually random, but not all 0s, used to generate a scrambling sequence.
- the transmitting end first generates a scrambling code sequence based on the initial state value of 7 bits, and then performs exclusive-OR operation on the first 7 bits of the scrambling code sequence and the 7-bit all-zero sequence of the initial value of the scrambling code generator, and the result is used as scrambling.
- the subsequent data is transmitted on the wireless channel; after receiving the scrambled data, the receiving end XORs the 7-bit all-zero sequence of the initial value of the scrambling code generator to obtain the first 7 bits of the transmitting end scrambling sequence.
- the receiving end can inversely derive the initial state value used by the transmitting end to generate the scrambling code sequence by using the 7-bit scrambling code sequence, thereby generating a scrambling code sequence identical to the transmitting end, for Receiver descrambling.
- the initial state value of the scrambling code generator is used to carry the verification information, that is, the verification information is used to replace the random value, and the receiving end needs to inversely derive the initial value according to the received initial value and combine the specific structure of the scrambling code generator to obtain the initial of the transmitting end.
- the status value (check information) is therefore implicit.
- the scrambling code generator is a 7-bit cyclic shift register. After a 7-bit initial value, a scrambling code sequence with a period of 127 can be output.
- the transmission frame source wireless device randomly selects a non-all-zero 7-bit binary sequence as the scrambling code generator initial state value.
- 6 bits (X1 to X6) in the check value are used instead of 6 bits in the 7-bit random sequence, and the remaining 1 bit is always set to 1 (to ensure The initial state values are not all 0).
- the 7-bit initial state value can be derived in reverse, and 6 bits are the contents of the check value.
- the initial value of the scrambling code generator implicitly carries the 6-bit check value (X1 to X6), and the 9-bit (X7-X15) directly carried by the service field, the check value may include at most 15 bits.
- the process is shown in Figure 2.
- the source wireless device transmitting the frame transmits the transmission frame
- other wireless devices that use the same wireless channel as the source wireless device will receive the transmission frame.
- the specific manner of determining whether the duration is a valid duration according to the check value is:
- the duration is a valid duration according to the first check value, that is, calculating a third check value of the field set included in the received transmission frame, and determining the first check. Whether the value matches the third check value. Among them, the first check value will match the third check value only when the check field and the field set are transmitted correctly.
- the matching can be equal or has a corresponding relationship. For example, if one side is inverted and equal to the other, it can be understood that there is a correspondence between the two parties.
- the first check value and the third check value are values directly calculated according to the field set by using a predetermined algorithm, and the first check value matches the third check value, that is, the first check value and the first check value
- the third check value is equal; it is assumed that the first check value is a value obtained by inverting the value calculated by the predetermined algorithm according to the field set, and the third check value is a value directly calculated according to the field set by using a predetermined algorithm, first The check value matches the third check value, that is, the value after the first check value is inverted is equal to the third check value or the value after the third check value is inverted is equal to the first check value.
- the predetermined algorithm may be a Cyclic Redundancy Code (CRC) algorithm.
- the NAV timer of the local end is updated by using the duration, that is, the time of the NAV timer is set to the duration. Value, so that the local end does not send data before the time of the NAV timer is decremented to zero, to prevent the data sent by the local end from causing interference to the data being transmitted in the same wireless channel; When the duration is invalid, the local NAV timer will not be updated.
- the transmission frame further includes a receiving address field
- the receiving address field includes a receiving address of the transmission frame
- the field set further includes a receiving address field
- the manner of updating the local NAV timer by using the duration is specifically as follows:
- the receiving address does not match the address of the local end, and the duration is longer than the time of the network allocation vector timer of the local end, the local NAV timer is updated with the duration.
- the third check value is calculated according to a predetermined set according to the field set, that is, the third check value is calculated according to a predetermined algorithm according to the duration field and the received address field. . Therefore, when the first check value matches the third check value, it can be indicated that the duration is the effective duration and the received address is a valid receive address. When the first check value does not match the third check value, it may indicate that the duration is an invalid duration, and/or the receiving address is an invalid receiving address.
- the transmission frame when the transmission frame includes the first check value, the duration, and the receiving address field, after receiving the transmission frame, first use the first check value to verify whether the duration is a valid duration, and whether the receiving address field is The effective address field, when the duration is the valid duration, and the receiving address field is a valid address field, it is determined whether the receiving address matches the address of the local end, and when the receiving address does not match the address of the local end (indicating that the transmission frame is not sent to the local address) The transmission frame of the terminal further determines whether the duration is greater than the time of the network allocation vector timer of the local end.
- the NAV timer of the local end is updated by using the duration; when receiving the address field If the address field is invalid, it indicates that the duration field is also an invalid field.
- the NAV timer of the local end will not be updated with the duration; when the receiving address field is a valid address field, and the receiving address matches the address of the local end, it indicates that the transmission frame is The transmission frame sent to the local end, continue to receive the other within the transmission frame ;
- a valid address field address field a receiver address does not match the address of the local, and the duration is less than or equal to the local network allocation vector timer time duration will not use the present updated NAV timer ends.
- the receiving address is the address of the destination wireless device that transmits the frame.
- the receiving address included in the transmission frame may be a unicast receiving address, a multicast receiving address, or a broadcast receiving address. Therefore, the address of the local end matches the receiving address, including the following situation: when receiving When the unicast receiving address matches the local address, the local address matches the receiving address.
- the receiving address is the multicast receiving address, the multicast receiving address is defined in the multicast group. If the address of the local end is included, the address of the local end matches the receiving address. When the receiving address is the broadcast receiving address, the local address matches the receiving address. In other cases, the address of the local end does not match the receiving address.
- the transmission frame further includes a physical header, and the physical header includes indication information, where the indication information is used to indicate that the transmission frame includes a check field.
- the transmission frame when the transmission frame includes a check field, a duration, a receiving address field, and indication information, after receiving the transmission frame, first use the indication information to determine whether the transmission frame includes a check field, and when the transmission frame includes a check field.
- the first check value is used to verify whether the receiving address field is a valid address field.
- the receiving address field is a valid address field, it is determined whether the receiving address matches the address of the local end.
- the receiving address does not match the address of the local end, Indicates that the transmission frame is not the transmission frame sent to the local end, and determines whether the duration is greater than the time of the network allocation vector timer of the local end.
- the local end NAV timer is updated by using the duration.
- the transmission frame does not include the check field, the subsequent operation will not be performed; when the transmission frame includes the check field, and the received address field is the invalid address field, it indicates that the duration field is also an invalid field, and the duration will not be utilized.
- Update the local NAV timer when the transmission frame includes a check field, receive the address word If the address is a valid address field, and the receiving address matches the address of the local end, it indicates that the transmission frame is a transmission frame sent to the local end, and continues to receive other contents of the transmission frame; when the transmission frame includes a check field, the receiving address field is a valid address field, When the receiving address does not match the local address and the duration is less than or equal to the time of the local network allocation vector timer, the local NAV timer will not be updated with the duration.
- the wireless device updates the local NAV timer by using the duration when the received transmission frame is a valid frame; when the received transmission frame is an invalid frame, the wireless device cannot set the NAV timing according to the duration.
- the device transmits data on the wireless channel, so that multiple wireless devices in the same wireless channel simultaneously transmit data at the same time, which reduces the reliability of virtual carrier sensing.
- the duration of the received transmission frame is determined according to the first check value carried in the check field by including a check field in the service field of the transport frame.
- the time is checked.
- the duration can be used to update the local NAV timer so that the local end does not send data until the time of the NAV timer is reduced to zero. To avoid the situation that multiple wireless devices simultaneously transmit data in the same wireless channel at the same time, thereby improving the reliability of virtual carrier sensing.
- FIG. 3 is a flowchart of another virtual carrier sensing method disclosed in an embodiment of the present invention.
- the virtual carrier sensing method shown in FIG. 3 is applicable to wireless devices such as mobile phones and tablet computers.
- the virtual carrier sensing method shown in FIG. 3 is described from the perspective of the transmitting side, and the related steps can be understood by referring to the foregoing.
- the virtual carrier sensing method may include the following steps.
- the transmission frame includes a service field and a duration field
- the service field includes a check field
- the check field carries a second check value
- the second check value is calculated according to a predetermined set according to the field set.
- the field set is a partial field in a field included in the transmission frame
- the field set includes a duration field
- the duration field includes a duration.
- the service field may carry the check value by using a basic method or an extended method.
- the basic method is as follows: the length of the service field is generally 16 bits, where 7 bits is the initial value of the scrambling code generator and cannot carry information. Therefore, the remaining 9 bits can be used to carry the check value.
- the 802.11ac standard has proposed to use 8 bits in the service field.
- the method of carrying the check value, but the check value is the check value of the VTH-SIG-B field in the physical header. Therefore, a similar method (that is, using some or all of the remaining 9 bits) can be used to carry the field.
- Set check value If the check value of the SIG field in the physical header needs to be carried, the field set will also include the SIG field in the physical header.
- the extension method further increases the check value length based on the basic method, specifically: implicitly carrying the initial state value of the scrambling code generator of the transmission frame source wireless device. Check the value to increase the length of the check value.
- the scrambling code generator is a 7-bit cyclic shift register. After a 7-bit initial value, a scrambling code sequence with a period of 127 can be output.
- the transmission frame source wireless device randomly selects a non-all-zero 7-bit binary sequence as the scrambling code generator initial state value.
- 6 bits (X1 to X6) of the check value are used instead of 6 bits in the 7-bit random sequence, and the remaining 1 bit is always set to 1 (in order to ensure that the initial state value is not all 0).
- the 7-bit initial state value can be derived in reverse, and 6 bits are the contents of the check value.
- the initial value of the scrambling code generator implicitly carries a 6-bit check value (X1 to X6), plus 9 bits directly carried by the service field. (X7 ⁇ X15), the check value can contain up to 15bits, the process is shown in Figure 2.
- the transmission frame further includes a receiving address field
- the receiving address field includes a receiving address of the transmission frame
- the field set further includes a receiving address field
- the receiving address of the transmission frame may be a unicast address, a broadcast address or a multicast address.
- the receiving address is the destination wireless device address of the transmission frame.
- the transmission frame further includes a physical header, and the physical header includes indication information, where the indication information is used to indicate that the transmission frame includes a check field.
- the value of the indication information in the physical header is 1, it indicates that the transmission frame includes a check field, and when the value of the indication information is 0, it indicates that the transmission frame does not include a check field.
- S302. Send a transmission frame, so that the wireless device that receives the transmission frame determines whether the duration is an effective duration according to the first check value, and updates the wireless device by using the duration when determining that the duration is the effective duration.
- a network allocation vector timer wherein the first check value is obtained after the second check value is carried in the check field and transmitted through the wireless channel.
- the transmission frame is sent to the wireless device corresponding to the receiving address, and in the process of transmitting, the wireless device corresponding to the receiving address uses the same wireless channel due to the broadcast characteristic of the wireless channel itself.
- the other wireless devices receive, so that the wireless devices use the first check value to determine whether the duration is a valid duration, and when the duration is determined to be a valid duration, the NAV timers will be updated with the duration to avoid the same time A situation in which multiple wireless devices simultaneously transmit data in the same wireless channel.
- the generated transmission frame includes a check field, and the check field carries a second check value, and the wireless device corresponding to the received address uses other wireless devices of the same wireless channel.
- the first check value is used to verify whether the duration is a valid duration, where the first check value is obtained after the second check value is carried in the check field and transmitted through the wireless channel.
- the time is the effective duration, the NAV timers will be updated with the duration to avoid the situation where multiple wireless devices simultaneously transmit data in the same wireless channel at the same time, thereby improving the reliability of virtual carrier sensing.
- FIG. 4 is a flowchart of a MAC frame header compression method according to an embodiment of the present invention.
- the MAC frame header compression method shown in FIG. 4 is applicable to wireless devices such as mobile phones and tablet computers.
- the MAC frame header compression method shown in FIG. 4 is described from the perspective of the transmitting side.
- the MAC frame header compression method may include the following steps.
- S401 Construct a transmission frame, where the transmission frame includes a physical header, a MAC frame header, and a frame check sequence.
- the MAC frame header includes a type of the transmission frame, a transmission direction of the transmission frame, and an address field set
- the physical header includes a direction for indicating whether the transmission frame is Compress the indication of the transmission frame.
- the short frame is short.
- Reduced wireless channel utilization One way to improve the short-band wireless channel utilization is to aggregate these short frames into long frames for transmission when a wireless device has multiple short frames to transmit. However, when these short frames belong to different users, they cannot be aggregated between them. Therefore, in this embodiment, starting from the MAC frame header of the short frame, the proportion of the transmission frame occupied by the MAC frame header is reduced by compressing the address field set in the MAC frame header.
- a transmission frame is constructed according to an existing rule, and the transmission frame includes a physical header, a MAC frame header, and a frame check sequence.
- the MAC frame header includes an address field set and a frame control field composed of at least one address field, wherein the frame control field includes a type of the transmission frame and a transmission direction of the transmission frame.
- the frame check sequence is calculated based on the MAC frame header and the frame body using a specific algorithm.
- the indication information may also be located in the SERVICE domain.
- the SERVICE field is located before the MAC frame header.
- S402. Determine an address field in the address field set that can be removed according to the type of the transmission frame and the transmission direction of the transmission frame.
- the type of the transmission frame may be a control frame, a data frame, a management frame, etc.
- the transmission direction of the transmission frame may be a downlink frame, an uplink frame, a direct connection frame, or the like.
- control frame generally includes a sending address and a receiving address of the frame, or only a receiving address, and these addresses can be removed and can be compressed.
- the sending address is the address of the source wireless device that transmits the frame
- the receiving address is the address of the destination wireless device that transmits the frame.
- the uplink frame and the downlink frame include a receiving address, a sending address, and a third address, and the receiving address and the sending address may be removed when the frame body
- the part is a MAC Service Data Unit (MSDU)
- the third address is the source wireless device address or the destination wireless device address (the device address outside the current Wi-Fi network), so the third address cannot be compressed;
- the frame part is an aggregated MSDU (Aggregate MSDU, A-MSDU), and the third address is a Basic Service Set Identifier (BSSID), that is
- the received transport frame body part is MSDU or A-MSDU?
- QoS Quality of Service
- Control Control
- the presence or absence of the third address will affect the relative position of the QoS Control field in the frame, that is, according to the QoS control field position, the receiver cannot first obtain an indication of the presence of the A-MSDU through the field, and then determine whether the third address exists. .
- the QoS Control field is referred to the position before all the address fields, so that the receiver can first check the indication of the presence of the A-MSDU in the QoS Control field, thereby determining whether the third address is compressed.
- the QoS control field location shift may occur before the FCS calculation, or may occur after the FCS calculation. This embodiment is not limited, but other devices should also perform corresponding reverse operations after receiving the transmission frame.
- Direct Connected Frames Includes two site addresses that are directly connected, and the addresses of the same access point associated with the two sites, all of which can be compressed.
- the management frame includes a receiving address, a sending address, and a third address, where the receiving address and the sending address may be compressed, and the third address may be a BSSID (an address of the access point) or a wildcarded BSSID, and the wildcard is matched.
- the BSSID cannot be compressed. Therefore, there are two schemes for managing the frame address field set compression: A) only receiving the address and sending address, the third address is always uncompressed; B) when the third address is the BSSID, the three address fields are compressed; When the three addresses are wildcard BSSIDs, the three address fields are not compressed. Since the third address in the actual network is mostly the BSSID, the scheme B is a preferred scheme.
- some auxiliary mechanisms may be employed.
- a basic scheme is to compress only one or more of the addresses, and the other addresses are not compressed. For example, in the uplink frame or the downlink frame, the receiving address is reserved, and the sending address is compressed; in the directly connected frame, the source station or destination is reserved. The address of the site, while compressing the address of the other site and the address of the access point.
- the short identifier of the sender device such as an association identifier (AID), a partial association identifier (Partial AID, PAID), etc., may be carried in the physical header or the MAC header of the transmission frame while compressing the address field set. .
- association identifier AID
- Partial AID partial association identifier
- PAID partial association identifier
- the transmission frame includes an aggregated MAC protocol data unit (Aggregate MAC)
- Aggregate MAC The protocol data unit (A-MPDU) uses the above address field removal rule for all MAC protocol data units (MPDUs) in the A-MPDU.
- the physical header includes a SIG field, and includes indication information for indicating whether the transmission frame is a compressed transmission frame. For example, when the value of the indication information is 1, it indicates that the transmission frame is a compressed transmission frame, and when the value of the indication information is 0, it indicates that the transmission frame is an uncompressed transmission frame.
- some or all of the address fields in the MAC frame header address field are removed before the transmission frame is transmitted, so as to reduce the MAC frame header length of the transmission frame and reduce the MAC frame.
- the proportion of the head occupied in the transmission frame thereby improving channel utilization.
- FIG. 5 is a flowchart of another MAC frame header compression method according to an embodiment of the present invention.
- the MAC frame header compression method shown in FIG. 5 is applicable to wireless devices such as mobile phones and tablet computers.
- the MAC frame header compression method shown in Fig. 5 is described from the perspective of the receiving side.
- the MAC frame header compression method may include the following steps.
- the S501 Receive a transmission frame, where the transmission frame includes a physical header, a MAC frame header, and a frame check sequence.
- the MAC frame header includes a type of the transmission frame, a transmission direction of the transmission frame, and an address field set, where the physical header includes indication information, and the indication information is used. Indicates that the transmission frame is a compressed transmission frame.
- the short frame is short.
- Reduced wireless channel utilization One way to improve the short-band wireless channel utilization is to aggregate these short frames into long frames for transmission when a wireless device has multiple short frames to transmit. However, when these short frames belong to different users, they cannot be aggregated between them. Therefore, in this embodiment, starting from the MAC frame header of the short frame, the ratio of the transmission frame occupied by the MAC frame header is reduced by compressing the address field in the MAC frame header.
- the indication information may also be located in the SERVICE domain.
- the SERVICE field is located before the MAC frame header.
- the indication information is included in the SIG field in the physical header of the transmission frame to indicate whether the transmission frame is a compressed transmission frame. For example, when the Compress bit of the SIG field is 1, it indicates that the transmission frame is a compressed transmission frame, and when the Compress bit of the transmission frame SIG field is 0, it indicates that the transmission frame is not a compressed transmission frame.
- the transmission frame may be a control frame, a data frame, a management frame, or the like.
- the transmission direction of the transmission frame may be a downlink frame, an uplink frame, a direct connection frame, or the like.
- the address field is determined to be moved by using the type of the transmission frame and the transmission direction of the transmission frame. Except the address.
- any one or more of the receiving address, the sending address, and the third address in the transmission frame may be compressed.
- the compressed receiving address and the sending address are taken as an example to illustrate how the receiving end recovers the compressed address field. Other situations are handled in a similar manner and will not be described here.
- adding the removed address to obtain the decompressed transmission frame may include the following steps.
- A1 The address of the wireless device associated with the local end is used as the sending address of the transmission frame, and the address of the local end is used as the receiving address of the transmission frame to obtain the transmission frame including the removed address.
- A3. Determine whether the target frame check sequence matches the frame check sequence included in the transmission frame.
- the transport frame including the removed address is used as the decompressed transmission frame.
- the removed address is composed of the sending device address of the transmission frame and the receiving address of the transmission frame
- the address of the wireless device associated with the local end is the transmission address of the transmission frame and the address of the local end is Transmitting a receiving address of the frame to obtain a transmission frame including the removed address, and then calculating a target frame check sequence of the transmission frame including the removed address by using a cyclic redundancy algorithm, and then determining the target frame check sequence and the transmission frame include Whether the frame check sequence matches, when the target frame check sequence matches the frame check sequence included in the transmission frame, it indicates that the assumption is established, and the transmission frame is sent by the associated wireless device to the present
- the transmission frame of the terminal the transmission frame including the removed address is used as the decompressed transmission frame; when the target frame check sequence does not match the frame check sequence, it indicates that the assumption is not established, and the transmission frame is not sent by the associated wireless device.
- the transmission frame of the end When the wireless device connected to the local end is a plurality of wireless devices
- some auxiliary mechanisms may be employed.
- a basic scheme is to compress only one or more of the addresses, and the other addresses are not compressed. For example, in the uplink frame or the downlink frame, the receiving address is reserved, and the sending address is compressed; in the directly connected frame, the source station or destination is reserved. The address of the site, while compressing the address of the other site and the address of the access point.
- a short identifier of the sender device such as an AID, a PAID, or the like, may be carried in the physical header or the MAC header of the transport frame while compressing the address field set.
- FIG. 6 is a structural diagram of a wireless device according to an embodiment of the present invention.
- the wireless device may be a mobile phone, a tablet, or the like, which is not limited in this embodiment.
- the wireless device 600 can include:
- the receiving unit 601 is configured to receive a transmission frame, where the transmission frame includes a service field and a duration field, where the service field includes a check field, the check field carries a first check value, and the first check value is a second school
- the verification value is obtained after being transmitted by the wireless channel in the check field, and the second check value is calculated by the predetermined algorithm according to the field set when the wireless device that transmits the transmission frame generates the transmission frame; wherein the field set is the transmission frame a partial field in the included field, the field set includes a duration field; the duration field includes a duration;
- the determining unit 602 is configured to determine, according to the first check value included in the transmission frame received by the receiving unit 601, whether the duration is a valid duration;
- the updating unit 603 is configured to update the NAV timer of the wireless device by using the duration of the transmission frame received by the receiving unit 601 when the determining unit 602 determines that the duration is the effective duration.
- the updating unit 603 is specifically configured to update the NAV timer of the wireless device by using the duration when the determining unit 602 determines that the duration is the effective duration.
- the determining unit 602 is specifically configured to:
- the transmission frame further includes a receiving address field
- the receiving address field includes a receiving address of the transmission frame
- the field set further includes a receiving address field
- the updating unit 603 is specifically configured to: when the duration is determined as the effective duration according to the first check value, and the receiving address is the valid receiving address, if the receiving address does not match the address of the wireless device, and the duration is greater than the wireless device
- the network allocation vector timer of the wireless device is updated with the duration.
- the transmission frame further includes a physical header, and the physical header includes indication information, where the indication information is used to indicate that the transmission frame includes a check field.
- the NAV timer of the local end is updated by using the duration; when the received transmission frame is invalid During the frame, the wireless device cannot set the NAV timer according to the duration, and the data is sent on the wireless channel, so that multiple wireless devices simultaneously transmit data in the same wireless channel at the same time, thereby reducing the reliability of virtual carrier sensing.
- the duration of the received transmission frame is determined according to the first check value carried in the check field by including a check field in the service field of the transport frame.
- the receiving address and duration included in the transmission frame need to be verified.
- the receiving address is a valid receiving address and the receiving address does not match the address of the local end, it is determined that the duration included in the transmission frame is a valid duration.
- the duration of the NAV timer is updated to prevent the local end from transmitting data before the time of the NAV timer is reduced to zero, thereby preventing multiple wireless devices from transmitting data simultaneously in the same wireless channel at the same time, thereby improving Virtual carrier sensing reliability.
- FIG. 7 is a structural diagram of another wireless device according to an embodiment of the present invention.
- the wireless device may be a mobile phone, a tablet, or the like, which is not limited in this embodiment.
- the no The line device 700 can include a processor 701, a memory 702, an input device 703, and an output device 704.
- the processor 701 and the memory 702, the processor 701 and the input device 703, the processor 701 and the output device 704 can be connected by a bus or other means.
- a bus connection is taken as an example. among them:
- the input device 703 is configured to receive the transmission frame and send it to the processor 701.
- the transmission frame includes a service field and a duration field, where the service field includes a check field, and the check field carries the first check value, the first school
- the verification value is obtained after the second check value is carried in the check field and transmitted by the wireless channel, and the second check value is calculated by the predetermined algorithm according to the field set when the wireless device that transmits the transmission frame generates the transmission frame;
- the field set is a partial field in a field included in the transmission frame, the field set includes a duration field; the duration field includes a duration;
- the memory 702 stores a set of program codes, and the processor 701 is configured to call the program code stored in the memory 702 to perform the following operations:
- the NAV timer of the wireless device is updated with the duration.
- the output device 704 is configured to send a message.
- the manner in which the processor 701 is configured to determine, according to the first check value, whether the duration is a valid duration is specifically:
- the processor 701 is configured to calculate, according to a set of fields, a third check value according to a predetermined algorithm
- the transmission frame further includes a receiving address field
- the receiving address field includes a receiving address of the transmission frame
- the field set further includes a receiving address field
- the manner in which the processor 701 is configured to update the network allocation vector timer of the wireless device by using the duration when determining that the duration is the effective duration is specifically:
- the processor 701 is configured to: when the duration is determined as the effective duration according to the first check value, and the receiving address is a valid receiving address, if the receiving address does not match the address of the wireless device, and the duration is greater than the network allocation of the wireless device.
- the time of the vector timer is updated with the duration of the network allocation vector timer of the wireless device.
- the transmission frame further includes a physical header, and the physical header includes indication information, where the indication information is used to indicate that the transmission frame includes a check field.
- the NAV timer of the local end is updated by using the duration; when the received transmission frame is invalid During the frame, the wireless device cannot set the NAV timer according to the duration, and the data is sent on the wireless channel, so that multiple wireless devices simultaneously transmit data in the same wireless channel at the same time, thereby reducing the reliability of virtual carrier sensing.
- the duration of the received transmission frame is determined according to the first check value carried in the check field by including a check field in the service field of the transport frame.
- the receiving address and duration included in the transmission frame need to be verified.
- the receiving address is a valid receiving address and the receiving address does not match the address of the local end, it is determined that the duration included in the transmission frame is a valid duration.
- the duration of the NAV timer is updated to prevent the local end from transmitting data before the time of the NAV timer is reduced to zero, thereby preventing multiple wireless devices from transmitting data simultaneously in the same wireless channel at the same time, thereby improving Virtual carrier sensing reliability.
- FIG. 8 is a structural diagram of still another wireless device according to an embodiment of the present invention.
- the wireless device may be a mobile phone, a tablet, or the like, which is not limited in this embodiment.
- the wireless device 800 can include:
- the generating unit 801 is configured to generate a transmission frame, where the transmission frame includes a service field and a duration field, where the service field includes a check field, the check field carries a second check value, and the second check value is pressed according to the field set
- the predetermined algorithm calculates that the field set is a partial field in a field included in the transmission frame, the field set includes a duration field, and the duration field includes a duration;
- the sending unit 802 is configured to send the transmission frame generated by the generating unit 801, so that the target wireless device that receives the transmission frame determines whether the duration is the effective duration according to the first check value, and when determining that the duration is the effective duration And updating, by using a duration, a network allocation vector timer of the target wireless device, where the first check value is obtained after the second check value is carried in the check field and transmitted through the wireless channel.
- the transmission frame further includes a receiving address field
- the receiving address field includes a receiving address of the transmission frame
- the field set further includes a receiving address field
- the transmission frame further includes a physical header, and the physical header includes indication information, where the indication information is used to indicate that the transmission frame includes a check field.
- the generated transmission frame includes a check field, and the check field carries a second check value, and is received by another wireless device that uses the same wireless channel by the wireless device corresponding to the received address.
- the first check value is used to verify whether the duration is a valid duration, wherein the first check value is obtained after the second check value is carried in the check field and transmitted through the wireless channel, and the duration is valid.
- the NAV timers will be updated with the duration to avoid the situation where multiple wireless devices simultaneously transmit data in the same wireless channel at the same time, thereby improving the reliability of virtual carrier sensing.
- FIG. 9 is a structural diagram of still another wireless device according to an embodiment of the present invention.
- the wireless device may be a mobile phone, a tablet, or the like, which is not limited in this embodiment.
- the wireless device 900 can include a processor 901, a memory 902, an output device 903, and an input device 904.
- the processor 901 and the memory 902, the processor 901 and the input device 903, the processor 901 and the input device 904 can be connected by a bus or other means.
- a bus connection is taken as an example. among them:
- the memory 902 stores a set of program codes
- the processor 901 is configured to call the program code stored in the memory 902 to perform the following operations:
- the transmission frame includes a service field and a duration field
- the service field includes a check field
- the check field carries a second check value
- the second check value is calculated according to a predetermined set of fields according to the field set
- the field A set is a partial field in a field included in a transport frame
- the set of fields includes a duration field
- the duration field includes a duration
- the output device 903 is configured to send a transmission frame, so that the target wireless device that receives the transmission frame determines whether the duration is an effective duration according to the first check value, and uses the duration when determining that the duration is the effective duration Updating a network allocation vector timer of the target wireless device, wherein the first check value is obtained after the second check value is carried in the check field and transmitted through the wireless channel.
- the wireless device 900 may further include an input device 904 for receiving a message.
- the transmission frame further includes a receiving address field
- the receiving address field includes a receiving address of the transmission frame
- the field set further includes a receiving address field
- the transmission frame further includes a physical header, and the physical header includes indication information, where the indication information is used to indicate that the transmission frame includes a check field.
- the generated transmission frame includes a check field, and the check field carries a second check value, and is received by another wireless device that uses the same wireless channel by the wireless device corresponding to the received address.
- the first check value is used to verify whether the duration is a valid duration, wherein the first check value is obtained after the second check value is carried in the check field and transmitted through the wireless channel, and the duration is valid.
- the NAV timers will be updated with the duration to avoid the situation where multiple wireless devices simultaneously transmit data in the same wireless channel at the same time, thereby improving the reliability of virtual carrier sensing.
- FIG. 10 is a structural diagram of still another wireless device according to an embodiment of the present invention.
- the wireless device may be a mobile phone, a tablet, or the like, which is not limited in this embodiment.
- the wireless device 1000 can include:
- the construction unit 1001 is configured to construct a transmission frame, where the transmission frame includes a physical header, a MAC frame header, and a frame check sequence, where the MAC frame header includes a type of the transmission frame, a transmission direction of the transmission frame, and an address field set, and the physical header includes an indication Whether the transmission frame is an indication of a compressed transmission frame;
- a determining unit 1002 configured to determine, according to a type of the transmission frame constructed by the building unit 1001 and a transmission direction of the transmission frame constructed by the building unit 1001, an address field in the address field set that can be removed;
- the removing unit 1003 is configured to remove the address that can be removed determined by the address field set determining unit 1002 constructed by the building unit 1001 to obtain a compressed MAC frame header;
- the obtaining unit 1004 is configured to set indication information in a physical header included in the transmission frame constructed by the construction unit 1001, so that the indication information is used to indicate that the transmission frame is a compressed transmission frame, to obtain a compressed transmission frame;
- the transmitting unit 1005 transmits the compressed transmission frame acquired by the obtaining unit 1004.
- the removing unit 1003 is configured to remove the address that can be removed determined by the address field concentration determining unit 1002 constructed by the building unit 1001 to obtain a compressed MAC frame header, and the trigger acquiring unit 1004 sets the constructing unit 1001. Transmitting the indication information in the physical header included in the frame, so that the indication information is used to indicate that the transmission frame is a compressed transmission frame, to obtain a compressed transmission frame.
- some or all of the address fields in the MAC frame header address field are removed before the transmission frame is transmitted, so as to reduce the MAC frame header length of the transmission frame and reduce the MAC frame header transmission.
- the proportion occupied in the frame thereby improving channel utilization.
- FIG. 11 is a structural diagram of still another wireless device according to an embodiment of the present invention.
- the wireless device may be a mobile phone, a tablet, or the like, which is not limited in this embodiment.
- the wireless device 1100 can include a processor 1101, a memory 1102, an output device 1103, and an input device 1104.
- the processor 1101 and the memory 1102, the processor 1101 and the output device 1103, the processor 1101 and the input device 1104 may be connected by a bus or other means.
- a bus connection is taken as an example. among them:
- the memory 1102 stores a set of program codes
- the processor 1101 is configured to call the program code stored in the memory 1102 to perform the following operations:
- the transmission frame includes a physical header, a MAC frame header, and a frame check sequence
- the MAC frame header includes a type of the transmission frame, a transmission direction of the transmission frame, and an address field set
- the physical header includes a direction for indicating whether the transmission frame is a compressed transmission.
- the output device 1103 is configured to send a compressed transmission frame.
- the input device 1104 is configured to receive a message.
- some or all of the address fields in the MAC frame header address field are first removed to reduce the MAC frame header length of the transmission frame, and the MAC frame header is reduced in transmission. The proportion occupied in the frame, thereby improving channel utilization.
- FIG. 12 is a structural diagram of still another wireless device according to an embodiment of the present invention.
- the wireless device may be a mobile phone, a tablet, or the like, which is not limited in this embodiment.
- the wireless device 1200 can include:
- the receiving unit 1201 is configured to receive a transmission frame, where the transmission frame includes a physical header, a MAC frame header, and a frame check sequence, where the MAC frame header includes a type of the transmission frame, a transmission direction of the transmission frame, and an address field set, and the physical header includes indication information.
- the indication information is used to indicate that the transmission frame is a compressed transmission frame;
- the determining unit 1202 is configured to determine, according to the indication information received by the receiving unit 1201, whether the transmission frame is To compress the transmission frame;
- a determining unit 1203 configured to: when the determining result of the determining unit 1202 is YES, use the type of the transmission frame acquired by the receiving unit 1201 and the transmission direction of the transmission frame acquired by the receiving unit 1201 to determine the address removed in the centralized setting;
- the adding unit 1204 is configured to add the removed address determined by the determining unit 1203 to obtain the decompressed transmission frame.
- the adding unit 1204 may include:
- the address obtaining subunit is configured to use an address of the target wireless device associated with the wireless device as a sending address of the transmission frame, and an address of the wireless device as a receiving address of the transmission frame, to obtain a transmission frame including the removed address.
- the sequence acquisition subunit is configured to calculate a target frame check sequence of the transmission frame including the removed address acquired by the address acquisition subunit.
- a determining subunit configured to determine whether the target frame check sequence acquired by the sequence obtaining subunit matches the frame check sequence included in the transmission frame received by the receiving unit 1201, and when the determining subunit determines that the yes result is The transmission frame except the address is used as the decompressed transmission frame.
- the transmission frame when the transmission frame is a compressed frame, part or all of the address fields in the MAC frame header address field are removed, and the length of the MAC frame header of the transmission frame is reduced, so that the MAC frame header is The proportion occupied in the transmission frame is reduced, thereby improving channel utilization.
- FIG. 13 is a structural diagram of still another wireless device according to an embodiment of the present invention.
- the wireless device may be a mobile phone, a tablet, or the like, which is not limited in this embodiment.
- the wireless device 1300 can include a processor 1301, a memory 1302, an input device 1303, and an output device 1304.
- the processor 1301 and the memory 1302, the processor 1301 and the input device 1303, the processor 1301 and the output device 1304 may be connected by a bus or other means.
- This embodiment takes a bus connection as an example. among them:
- the input device 1303 is configured to receive a transmission frame, where the transmission frame includes a physical header, a MAC frame header, and a frame check sequence, where the MAC frame header includes a type of the transmission frame, a transmission direction of the transmission frame, and an address field set, and the physical header includes indication information.
- the indication information is used to indicate that the transmission frame is a compressed transmission frame;
- a set of program codes is stored in the memory 1302, and the processor 1301 is configured to call the memory 1302.
- the program code stored in it does the following:
- the address removed in the address field set is determined according to the type of the transmission frame and the transmission direction of the transmission frame;
- the output device 1304 is configured to send a message.
- the manner in which the processor 1301 adds the removed address to obtain the decompressed transmission frame is specifically:
- the address of the target wireless device associated with the wireless device is used as the sending address of the transmission frame, and the address of the wireless device is used as the receiving address of the transmission frame to obtain a transmission frame including the removed address;
- the transmission frame including the removed address is used as the decompressed transmission frame.
- the transmission frame is a compressed frame
- part or all of the addresses in the MAC frame header address field are removed, and the length of the MAC frame header of the transmission frame is reduced, so that the MAC frame header is transmitted.
- the proportion occupied in the frame is reduced, thereby improving channel utilization.
- an embodiment of the present invention further discloses a computer storage medium storing a computer program.
- the computer program in the computer storage medium is read into a computer, the computer can cause the computer to complete the disclosure of the embodiment of the present invention. All steps of the virtual carrier sensing method.
- the storage medium may include a flash disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.
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Abstract
一种虚拟载波侦听方法及装置,其中,该方法包括:接收传输帧,传输帧包括服务字段和持续时间字段,其中,服务字段包括校验字段,校验字段中携带有第一校验值,第一校验值是第二校验值被携带在校验字段中经过无线信道传输后得到的,第二校验值是发送传输帧的无线设备生成传输帧时根据字段集按预定算法计算得到的;其中,字段集是传输帧包括的字段中的部分字段,字段集包括持续时间字段;持续时间字段包括持续时间(S101);根据第一校验值来确定持续时间是否为有效持续时间(S102);当确定持续时间为有效持续时间时,利用持续时间更新本端的网络分配矢量计时器(S103)。该方法可以提高虚拟载波侦听可靠性。
Description
本发明涉及通信技术领域,尤其涉及一种虚拟载波侦听方法及装置。
虚拟载波侦听(Virtual Carrier Sense,VCS)是电气和电子工程师协会(Institute of Electrical and Electronics Engineers,IEEE)802.11标准中一种重要传输保护机制。在VCS机制中,数据以传输帧的形式进行传输,传输帧包括物理头和数据,数据包括服务(SERVICE)字段和物理层汇聚过程服务数据单元(Physical Layer Convergence Procedure Service Data Unit,PSDU)。PSDU是媒体访问控制(Media Access Control,MAC)层数据,包括MAC帧头、帧体和帧校验序列(Frame Check Sequence,FCS)。MAC帧头包括持续时间字段,用于指示源无线设备与目的无线设备之间传输包括传输帧的数据的预期剩余时间。
目前,常见的虚拟载波侦听方法为:当传输帧由源无线设备通过一个无线信道向目的无线设备传输时,与这两个无线设备使用同一无线信道的其它无线设备可能接收到该传输帧包括的所有内容,之后利用FCS判断该传输帧是否为有效帧,当该传输帧为有效帧时,根据该传输帧包括的持续时间字段设置网络分配矢量(Network Allocation Vector,NAV)计时器。在NAV计时器递减为零之前,这些无线设备即使侦听到该无线信道空闲,也无法通过该无线信道发送数据,以避免对正在该无线信道上传输数据的无线设备造成干扰。
在上述方法中,当传输帧为无效帧时,这些设备无法根据该持续时间设置NAV计时器,就会在该无线信道发送数据,以致在同一时间同一无线信道中出现多个无线设备同时发送数据,降低了虚拟载波侦听可靠性。
发明内容
本发明实施例公开了一种虚拟载波侦听方法及装置,用于提高虚拟载波侦听可靠性。
本发明实施例第一方面公开一种虚拟载波侦听方法,包括:
接收传输帧,所述传输帧包括服务字段和持续时间字段,其中,所述服务字段包括校验字段,所述校验字段中携带有第一校验值,所述第一校验值是第二校验值被携带在所述校验字段中经过无线信道传输后得到的,所述第二校验值是发送所述传输帧的无线设备生成所述传输帧时根据字段集按预定算法计算得到的;其中,所述字段集是所述传输帧包括的字段中的部分字段,所述字段集包括所述持续时间字段;所述持续时间字段包括持续时间;
根据所述第一校验值来确定所述持续时间是否为有效持续时间;
当确定所述持续时间为有效持续时间时,利用所述持续时间更新本端的NAV计时器。
结合本发明实施例第一方面,在本发明实施例第一方面的第一种可能的实现方式中,所述根据所述第一校验值来确定所述持续时间是否为有效持续时间,包括:
根据所述字段集按所述预定算法计算得到第三校验值;
当所述第一校验值与所述第三校验值匹配时,确定所述持续时间为有效持续时间。
结合本发明实施例第一方面或本发明实施例第一方面的第一种可能的实现方式,在本发明实施例第一方面的第二种可能的实现方式中,所述传输帧还包括接收地址字段,所述接收地址字段包括所述传输帧的接收地址,所述字段集还包括所述接收地址字段;
所述当确定所述持续时间为有效持续时间时,利用所述持续时间更新本端的NAV计时器包括:
当根据所述第一校验值确定所述持续时间为有效持续时间、所述接收地址为有效接收地址时,若所述接收地址与本端的地址不匹配,且所述持续时间大于本端的NAV计时器的时间,利用所述持续时间更新本端的NAV计时器。
结合本发明实施例第一方面的第二种可能的实现方式,在本发明实施例第一方面的第三种可能的实现方式中,所述传输帧还包括物理头,所述物理头包括指示信息,所述指示信息用于指示所述传输帧包括所述校验字段。
本发明实施例第二方面公开一种虚拟载波侦听方法,包括:
生成传输帧,所述传输帧包括服务字段和持续时间字段,其中,所述服务字段包括校验字段,所述校验字段中携带有第二校验值,所述第二校验值根据字段集按预定算法计算得到,所述字段集是所述传输帧包括的字段中的部分字段,所述字段集包括所述持续时间字段,所述持续时间字段包括持续时间;
发送所述传输帧,以使接收到所述传输帧的无线设备根据第一校验值来确定所述持续时间是否为有效持续时间,并当确定所述持续时间为有效持续时间时,利用所述持续时间更新该无线设备的网络分配矢量计时器,其中,所述第一校验值是所述第二校验值被携带在所述校验字段中经过无线信道传输后得到的。
结合本发明实施例第二方面,在本发明实施例第二方面的第一种可能的实现方式中,所述传输帧还包括接收地址字段,所述接收地址字段包括所述传输帧的接收地址,所述字段集还包括所述接收地址字段。
结合本发明实施例第二方面的第一种可能的实现方式,在本发明实施例第二方面的第二种可能的实现方式中,所述传输帧还包括物理头,所述物理头包括指示信息,所述指示信息用于指示所述传输帧包括所述校验字段。
本发明实施例第三方面公开一种无线设备,包括:
接收单元,用于接收传输帧,所述传输帧包括服务字段和持续时间字段,其中,所述服务字段包括校验字段,所述校验字段中携带有第一校验值,所述第一校验值是第二校验值被携带在所述校验字段中经过无线信道传输后得到的,所述第二校验值是发送所述传输帧的无线设备生成所述传输帧时根据字段集按预定算法计算得到的;其中,所述字段集是所述传输帧包括的字段中的部分字段,所述字段集包括所述持续时间字段;所述持续时间字段包括持续时间;
判断单元,用于根据所述接收单元接收的传输帧包括的第一校验值来确定所述持续时间是否为有效持续时间;
更新单元,用于当所述判断单元确定所述持续时间为有效持续时间时,利用所述持续时间更新所述无线设备的NAV计时器。
结合本发明实施例第三方面,在本发明实施例第三方面的第一种可能的实现方式中,所述判断单元具体用于:
根据所述字段集按所述预定算法计算得到第三校验值;
当所述第一校验值与所述第三校验值匹配时,确定所述持续时间为有效持续时间。
结合本发明实施例第三方面或本发明实施例第三方面的第一种可能的实现方式,在本发明实施例第三方面的第二种可能的实现方式中,所述传输帧还包括接收地址字段,所述接收地址字段包括所述传输帧的接收地址,所述字段集还包括所述接收地址字段;
所述更新单元,具体用于当根据所述第一校验值确定所述持续时间为有效持续时间、所述接收地址为有效接收地址时,若所述接收地址与所述无线设备的地址不匹配,且所述持续时间大于所述无线设备的NAV计时器的时间,则利用所述持续时间更新所述无线设备的NAV计时器。
结合本发明实施例第三方面的第二种可能的实现方式,在本发明实施例第三方面的第三种可能的实现方式中,所述传输帧还包括物理头,所述物理头包括指示信息,所述指示信息用于指示所述传输帧包括所述校验字段。
本发明实施例第四方面公开一种无线设备,包括处理器、存储器和输入装置,其中:
所述输入装置,用于接收传输帧并发送给所述处理器,所述传输帧包括服务字段和持续时间字段,其中,所述服务字段包括校验字段,所述校验字段中携带有第一校验值,所述第一校验值是第二校验值被携带在所述校验字段中经过无线信道传输后得到的,所述第二校验值是发送所述传输帧的无线设备生成所述传输帧时根据字段集按预定算法计算得到的;其中,所述字段集是所述传输帧包括的字段中的部分字段,所述字段集包括所述持续时间字段;所述持续时间字段包括持续时间;
所述存储器中存储有一组程序代码,所述处理器用于调用所述存储器中存储的程序代码执行以下操作:
根据所述第一校验值来确定所述持续时间是否为有效持续时间;
当确定所述持续时间为有效持续时间时,利用所述持续时间更新所述无线设备的NAV计时器。
结合本发明实施例第四方面,在本发明实施例第四方面的第一种可能的实现方式中,所述处理器用于根据所述第一校验值来确定所述持续时间是否为有效持续时间的方式具体为:
所述处理器用于根据所述字段集按所述预定算法计算得到第三校验值;
当所述第一校验值与所述第三校验值匹配时,确定所述持续时间为有效持续时间。
结合本发明实施例第四方面或本发明实施例第四方面的第一种可能的实现方式,在本发明实施例第四方面的第二种可能的实现方式中,所述传输帧还包括接收地址字段,所述接收地址字段包括所述传输帧的接收地址,所述字段集还包括所述接收地址字段;
所述处理器用于当确定所述持续时间为有效持续时间时,利用所述持续时间更新本端的NAV计时器的方式具体为:
所述处理器用于当根据所述第一校验值确定所述持续时间为有效持续时间、所述接收地址为有效接收地址时,若所述接收地址与所述无线设备的地址不匹配,且所述持续时间大于所述无线设备的NAV计时器的时间,则利用所述持续时间更新所述无线设备的NAV计时器。
结合本发明实施例第四方面的第二种可能的实现方式,在本发明实施例第四方面的第三种可能的实现方式中,所述传输帧还包括物理头,所述物理头包括指示信息,所述指示信息用于指示所述传输帧包括所述校验字段。
本发明实施例第五方面公开一种无线设备,包括:
生成单元,用于生成传输帧,所述传输帧包括服务字段和持续时间字段,其中,所述服务字段包括校验字段,所述校验字段中携带有第二校验值,所述第二校验值根据字段集按预定算法计算得到,所述字段集是所述传输帧包括的字段中的部分字段,所述字段集包括所述持续时间字段,所述持续时间字段包括持续时间;
发送单元,用于发送所述生成单元生成的传输帧,以使接收到所述传输帧的目标无线设备根据第一校验值来确定所述持续时间是否为有效持续时间,并当确定所述持续时间为有效持续时间时,利用所述持续时间更新该目标无线设
备的网络分配矢量计时器,其中,所述第一校验值是所述第二校验值被携带在所述校验字段中经过无线信道传输后得到的。
结合本发明实施例第五方面,在本发明实施例第五方面的第一种可能的实现方式中,所述传输帧还包括接收地址字段,所述接收地址字段包括所述传输帧的接收地址,所述字段集还包括所述接收地址字段。
结合本发明实施例第五方面的第一种可能的实现方式,在本发明实施例第五方面的第二种可能的实现方式中,所述传输帧还包括物理头,所述物理头包括指示信息,所述指示信息用于指示所述传输帧包括所述校验字段。
本发明实施例第六方面公开一种无线设备,包括处理器、存储器和输出装置,其中:
所述存储器中存储有一组程序代码,所述处理器用于调用所述存储器中存储的程序代码执行以下操作:
生成传输帧,所述传输帧包括服务字段和持续时间字段,其中,所述服务字段包括校验字段,所述校验字段中携带有第二校验值,所述第二校验值根据字段集按预定算法计算得到,所述字段集是所述传输帧包括的字段中的部分字段,所述字段集包括所述持续时间字段,所述持续时间字段包括持续时间;
所述输出装置,用于发送所述传输帧,以使接收到所述传输帧的目标无线设备根据第一校验值来确定所述持续时间是否为有效持续时间,并当确定所述持续时间为有效持续时间时,利用所述持续时间更新该目标无线设备的网络分配矢量计时器,其中,所述第一校验值是所述第二校验值被携带在所述校验字段中经过无线信道传输后得到的。
结合本发明实施例第六方面,在本发明实施例第六方面的第一种可能的实现方式中,所述传输帧还包括接收地址字段,所述接收地址字段包括所述传输帧的接收地址,所述字段集还包括所述接收地址字段。
结合本发明实施例第六方面的第一种可能的实现方式,在本发明实施例第六方面的第二种可能的实现方式中,所述传输帧还包括物理头,所述物理头包括指示信息,所述指示信息用于指示所述传输帧包括所述校验字段。
现有方法中,无线设备只有当接收的传输帧为有效帧时,才利用持续时间
更新本端的NAV计时器;当接收的传输帧为无效帧时,该无线设备无法根据该持续时间设置NAV计时器,就会在该无线信道发送数据,以致在同一时间同一无线信道中出现多个无线设备同时发送数据,降低了虚拟载波侦听可靠性。在本发明实施例提供的虚拟载波侦听方法中,通过在传输帧的服务字段里包括校验字段,根据该校验字段中携带的第一校验值来确定接收的传输帧包括的持续时间是否为有效持续时间,不论接收的传输帧是否为有效帧,即不需要对传输帧整个帧利用FCS判断该传输帧是否为有效帧,只需要对传输帧里包括的持续时间进行校验,当确定传输帧里包括的持续时间为有效持续时间时,就可以利用持续时间来更新本端的NAV计时器,以使本端在NAV计时器的时间递减为零之前不发送数据,避免同一时间同一无线信道中出现多个无线设备同时发送数据的情况,从而可以提高虚拟载波侦听可靠性。
为了更清楚地说明本发明实施例中的技术方案,下面将对实施例中所需要使用的附图作简单地介绍,显而易见地,下面描述中的附图是本发明的一些实施例,对于本领域普通技术人员来讲,在不付出创造性劳动性的前提下,还可以根据这些附图获得其他的附图。
图1是本发明实施例公开的一种虚拟载波侦听方法的流程图;
图2是本发明实施例公开的利用扰码生成器携带校验值的过程;
图3是本发明实施例公开的另一种虚拟载波侦听方法是流程图;
图4是本发明实施例公开的一种MAC帧头压缩方法的流程图;
图5是本发明实施例公开的另一种MAC帧头压缩方法的流程图;
图6是本发明实施例公开的一种无线设备的结构图;
图7是本发明实施例公开的另一种无线设备的结构图;
图8是本发明实施例公开的又一种无线设备的结构图;
图9是本发明实施例公开的又一种无线设备的结构图;
图10是本发明实施例公开的又一种无线设备的结构图;
图11是本发明实施例公开的又一种无线设备的结构图;
图12是本发明实施例公开的又一种无线设备的结构图;
图13是本发明实施例公开的又一种无线设备的结构图。
下面将结合本发明实施例中的附图,对本发明实施例中的技术方案进行清楚、完整地描述,显然,所描述的实施例仅是本发明一部分实施例,而不是全部的实施例。基于本发明中的实施例,本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例,都属于本发明保护的范围。
本发明实施例公开了一种虚拟载波侦听方法及装置,用于提高虚拟载波侦听可靠性。以下分别进行详细说明。
由于无线信道的不可靠性,传输帧的传输可能出错,导致接收端收到的传输帧内容不同于发送端产生的内容。现有技术中,为了使接收端能够获知接收到的传输帧正确与否,发送端在传输帧中增加了额外的校验数据,即将传输帧内容输入预定校验算法,获得发送校验值,然后携带在传输帧中的帧校验字段中发送。接收端收到传输帧后,对传输帧内容采用与接收端相同的校验算法进行计算,获得接收校验值,然后将其与从接收到的传输帧中获得的发送校验值进行比较。若两者匹配,则认为传输帧内容接收正确,即该传输帧为有效帧;若不匹配,则说明传输帧内容在传输过程中出错,或者发送校验值传输出错,即该传输帧为无效帧,此时,接收端丢弃该传输帧。
因无线信道不可靠所导致的错误可能出现在传输帧中任何位置。当设备收到一个无效的传输帧(即帧校验值匹配结果为不匹配时),传输帧中的持续时间字段仍然有可能是正确的,此时,持续时间字段中持续时间仍可用来设置自己的NAV计时器,但现有技术中当接收到一个无效的传输帧时就丢弃该帧了,没有利用该无效的传输帧中依然有效的持续时间的信息。因此,需要一种机制,使得接收端即使在接收到的传输帧整体传输错误情况下,也能判断该传输帧中持续时间字段是否出错。
另一方面,从实现的角度来讲,由于帧校验字段位于帧的尾部,当设备收到一个传输帧,并根据帧头中的接收地址域确定该帧不需要自己接收时,会直接丢弃该帧,而不会再继续接收传输帧的后续部分,以便节省能量。这种情况下,接收设备根本无从判断持续时间字段接收正确与否。若其接收错误,使用
其设置NAV计时器可能导致不可预测的问题。因此,需要在无线设备只接收帧头的情况下,能够准确判断持续时间字段是否接收正确。
综上所述,需要在传输帧中帧头及之前的位置增添新的校验字段,对持续时间字段进行校验。该方法使得接收无线设备能够在只接收部分传输帧的情况下即可判断持续时间字段是否接收正确,从而使NAV计时器正确设置,且能够节省能量;同时,即使在收到一个无效传输帧的情况下,接收无线设备也能够单独判断持续时间字段是否接收正确,从而利用其设置NAV计时器。相比现有的方法,本发明实施例提供的方法使得无线设备能够在更多情况下获得有效持续时间,从而使虚拟载波侦听机制更加有效。
请参阅图1,图1是本发明实施例公开的一种虚拟载波侦听方法的流程图。其中,图1所示的虚拟载波侦听方法适用于手机、平板电脑等无线设备。图1所示的虚拟载波侦听方法是从接收侧的角度来描述的。如图1所示,该虚拟载波侦听方法可以包括以下步骤。
S101、接收传输帧,传输帧包括服务字段和持续时间字段,其中,服务字段包括校验字段,校验字段中携带有第一校验值,第一校验值是第二校验值被携带在校验字段中经过无线信道传输后得到的,第二校验值是发送传输帧的无线设备生成传输帧时根据字段集按预定算法计算得到的;其中,字段集是传输帧包括的字段中的部分字段,字段集包括持续时间字段;持续时间字段包括持续时间。
本实施例中,接收到的传输帧包括物理头和数据,数据包括服务字段、PSDU、尾(Tail)和填充(Pad)。其中,在某些情况下,数据中不存在尾和填充两部分。PSDU是MAC层数据,PSDU包括MAC帧头、帧体和FCS,MAC帧头包括持续时间字段,持续时间字段包括持续时间。服务字段包括校验字段、扰码生成器初始值(Scrambler Initialization),其中,校验字段中携带有第一校验值,第一校验值是第二校验值被携带在校验字段中经过无线信道传输后得到的,第二校验值是发送传输帧的无线设备生成传输帧时根据字段集按预定算法计算得到的;其中,字段集是传输帧包括的字段中的部分字段,字段集包括持续时间字段;持续时间字段包括持续时间。其中,第一校验值与第二校验值可
能相等,也可能不相等;当在传输过程中校验字段传输出错时,两者不相等;当在传输过程中校验字段传输正确时,两者相等。
本实施例中,服务字段可以通过基本方法或扩展方法承载校验值。基本方法为:服务字段的长度一般为16bits,其中,7bits为扰码生成器初始值,不能携带信息,因此,可以用剩余的9bits携带校验值,802.11ac标准中已提出利用服务字段中8bits承载校验值的方法,但该校验值是物理头中的VTH-SIG-B字段的校验值,因此,可以采用类似的方法(即利用剩余的9bits中的部分或全部bits)承载字段集的校验值,如果需要承载物理头中的SIG字段的校验值,则字段集将还包括物理头中的SIG字段。校验值长度越短越易产生误判,因此,扩展方法在基本方法的基础上进一步增加校验值长度,具体为:通过传输帧源无线设备的扰码生成器初始状态值隐式地承载校验值,以增加校验值长度。
本实施例中,扰码生成器初始值(Initialization)和初始状态值(Initial State)是两个不同的概念。前者是SERVICE字段中一个子字段的名字,长度为7bits,通常取固定值,例如当前802.11标准中取7bits全0序列;后者是扰码生成器中7位移位寄存器的初始取值,长度为7bits,通常随机取值但不能为全0,用于生成扰码序列。实际传输中,发送端首先基于7bits初始状态值产生扰码序列,然后用扰码序列中的前7bits与扰码生成器初始值的7bits全0序列分别进行异或操作,将其结果作为加扰后的数据在无线信道上发送;接收端接收到该加扰数据后,将其再次与扰码生成器初始值的7bits全0序列进行异或,从而得到发送端扰码序列的前7bits。根据扰码生成器的具体构造,接收端可由这7bits扰码序列反向推导出发送端生成该扰码序列时所使用的初始状态值,进而产生和发送端完全相同的扰码序列,用于接收端解扰。使用扰码生成器初始状态值携带校验信息,即用校验信息取代随机取值,接收端需根据接收到的初始值加扰结果并结合扰码生成器具体结构反向推导得到发送端的初始状态值(校验信息),故属于隐式传输。
举例说明,扰码生成器是一个7位的循环移位寄存器,给定7位初始值之后,可输出周期为127的扰码序列。传统机制中,传输帧源无线设备随机选择一个非全0的7位二进制序列作为扰码生成器初始状态值。而在扩展方法中,用校验值中的6位(X1~X6)代替7位随机序列中的6位,剩余1位恒置为1(为了保证
初始状态值不全为0)。其它无线设备接收到传输帧后,可反向推导出这7位初始状态值,其中6位是检验值的内容。该方法中通过扰码生成器初始状态值隐式携带6位校验值(X1~X6),加上由服务字段直接携带的9位(X7~X15),则校验值最多可以包含15bits,其过程如图2所示。
本实施例中,当传输帧的源无线设备发送传输帧时,与该源无线设备使用同一无线信道的其它无线设备将会接收到传输帧。
S102、根据第一校验值来确定持续时间是否为有效持续时间。
作为一种可能的实施方式,根据校验值来确定持续时间是否为有效持续时间的具体方式为:
根据字段集按预定算法计算得到第三校验值;
当第一校验值与第三校验值匹配时,确定持续时间为有效持续时间。
本实施例中,接收到传输帧后,将根据第一校验值来确定持续时间是否为有效持续时间,即计算接收的传输帧包括的字段集的第三校验值,判断第一校验值与第三校验值是否匹配。其中,只有当校验字段和字段集都传输正确,第一校验值才会与第三校验值匹配。匹配,可以是相等,或者是有对应关系,比如将一方取反后与另一方相等,可以理解为两方有对应关系。
举例说明,假设第一校验值和第三校验值都是利用预定算法根据字段集直接计算得到的值,第一校验值与第三校验值匹配,即第一校验值与第三校验值相等;假设第一校验值是利用预定算法根据字段集计算得到的值取反之后的值,而第三校验值是利用预定算法根据字段集直接计算得到的值,第一校验值与第三校验值匹配,即将第一校验值取反后的值与第三校验值相等或将第三校验值取反后的值与第一校验值相等。其中,预定算法可以为循环冗余校验(Cyclic Redundancy Code,CRC)算法。
S103、当确定持续时间为有效持续时间时,利用持续时间更新本端的NAV计时器。
本实施例中,当确定持续时间为有效持续时间,即第一校验值与第三校验值匹配时,利用持续时间更新本端的NAV计时器,即将NAV计时器的时间设置为持续时间的值,以使本端在NAV计时器的时间递减为零之前不发送数据,以避免本端发送的数据对同一无线信道中正在传输的数据造成干扰;当持续时间
为无效持续时间时,将不更新本端的NAV计时器。
作为一种可能的实施方式,传输帧还包括接收地址字段,接收地址字段包括传输帧的接收地址,字段集还包括接收地址字段;
当确定持续时间为有效持续时间时,利用持续时间更新本端的NAV计时器的方式具体为:
当持续时间为有效持续时间,接收地址与本端的地址不匹配,且持续时间大于本端的网络分配矢量计时器的时间时,利用持续时间更新本端的NAV计时器。
本实施例中,当传输帧包括持续时间字段和接收地址字段时,根据字段集按预定算法计算得到第三校验值,即根据持续时间字段和接收地址字段按预定算法计算第三校验值。因此,当第一校验值与第三校验值匹配时,可以表明持续时间为有效持续时间,且接收地址为有效接收地址。当第一校验值与第三校验值不匹配时,可以表明持续时间为无效持续时间,和/或,接收地址为无效接收地址。
本实施例中,当传输帧包括第一校验值、持续时间和接收地址字段时,接收到传输帧后,先利用第一校验值验证持续时间是否为有效持续时间、接收地址字段是否为有效地址字段,当持续时间为有效持续时间,且接收地址字段为有效地址字段时,判断接收地址是否与本端的地址匹配,当接收地址与本端的地址不匹配时(表明传输帧不是发送给本端的传输帧),进一步判断持续时间是否大于本端的网络分配矢量计时器的时间,当持续时间大于本端的网络分配矢量计时器的时间时,利用持续时间更新本端的NAV计时器;当接收地址字段为无效地址字段时,表明持续时间字段也为无效字段,将不利用持续时间更新本端的NAV计时器;当接收地址字段为有效地址字段,且接收地址与本端的地址匹配时,表明传输帧是发送给本端的传输帧,继续接收传输帧的其它内容;当接收地址字段为有效地址字段,接收地址与本端的地址不匹配,且持续时间小于或等于本端的网络分配矢量计时器的时间时,将不利用持续时间更新本端的NAV计时器。其中,接收地址为传输帧的目的无线设备的地址。
本实施例中,传输帧包括的接收地址可以是单播接收地址、组播接收地址或广播接收地址,因此,本端的地址与接收地址匹配包括以下情况:当接收地
址为单播接收地址时,单播接收地址与本端的地址匹配时,表明本端的地址与接收地址匹配;当接收地址为组播接收地址时,如果组播接收地址所定义的组播组中包括本端的地址,则表明本端的地址与接收地址匹配;当接收地址为广播接收地址,表明本端的地址与接收地址匹配。其它情况均视为本端的地址与接收地址不匹配。
作为一种可能的实施方式,传输帧还包括物理头,物理头包括指示信息,指示信息用于指示传输帧包括校验字段。
本实施例中,当传输帧包括校验字段、持续时间、接收地址字段和指示信息时,接收到传输帧后,先利用指示信息判断传输帧是否包括校验字段,当传输帧包括校验字段时,将利用第一校验值验证接收地址字段是否为有效地址字段,当接收地址字段为有效地址字段时,判断接收地址是否与本端的地址匹配,当接收地址与本端的地址不匹配时,表明传输帧不是发送给本端的传输帧,判断持续时间是否大于本端的网络分配矢量计时器的时间,当持续时间大于本端的网络分配矢量计时器的时间时,利用持续时间更新本端的NAV计时器;当传输帧不包括校验字段时,将不执行后续的操作;当传输帧包括校验字段,且接收地址字段为无效地址字段时,表明持续时间字段也为无效字段,将不利用持续时间更新本端的NAV计时器;当传输帧包括校验字段,接收地址字段为有效地址字段,且接收地址与本端的地址匹配时,表明传输帧是发送给本端的传输帧,继续接收传输帧的其它内容;当传输帧包括校验字段,接收地址字段为有效地址字段,接收地址与本端的地址不匹配,且持续时间小于或等于本端的网络分配矢量计时器的时间时,将不利用持续时间更新本端的NAV计时器。
现有方法中,无线设备只有当接收的传输帧为有效帧时,才利用持续时间更新本端的NAV计时器;当接收的传输帧为无效帧时,该无线设备无法根据该持续时间设置NAV计时器,就会在该无线信道发送数据,以致在同一时间同一无线信道中出现多个无线设备同时发送数据,降低了虚拟载波侦听可靠性。在本发明实施例提供的虚拟载波侦听方法中,通过在传输帧的服务字段里包括校验字段,根据该校验字段中携带的第一校验值来确定接收的传输帧包括的持续时间是否为有效持续时间,不论接收的传输帧是否为有效帧,即不需要对传输帧整个帧利用FCS判断该传输帧是否为有效帧,只需要对传输帧里包括的持续
时间进行校验,当确定传输帧里包括的持续时间为有效持续时间时,就可以利用持续时间来更新本端的NAV计时器,以使本端在NAV计时器的时间递减为零之前不发送数据,避免同一时间同一无线信道中出现多个无线设备同时发送数据的情况,从而可以提高虚拟载波侦听可靠性。
请参阅图3,图3是本发明实施例公开的另一种虚拟载波侦听方法的流程图。其中,图3所示的虚拟载波侦听方法适用于手机、平板电脑等无线设备。图3所示的虚拟载波侦听方法是从发送侧的角度来描述的,相关步骤可以参考前述内容进行理解。如图3所示,该虚拟载波侦听方法可以包括以下步骤。
S301、生成传输帧,传输帧包括服务字段和持续时间字段,其中,服务字段包括校验字段,校验字段中携带有第二校验值,第二校验值根据字段集按预定算法计算得到,字段集是传输帧包括的字段中的部分字段,字段集包括持续时间字段,持续时间字段包括持续时间。
本实施例中,服务字段可以通过基本方法或扩展方法承载校验值。基本方法为:服务字段的长度一般为16bits,其中,7bits为扰码生成器初始值,不能携带信息,因此,可以用剩余的9bits携带校验值,802.11ac标准中已提出利用服务字段中8bits承载校验值的方法,但该校验值是物理头中的VTH-SIG-B字段的校验值,因此,可以采用类似的方法(即利用剩余的9bits中的部分或全部bits)承载字段集的校验值,如果需要承载物理头中的SIG字段的校验值,则字段集将还包括物理头中的SIG字段。校验值长度越短越易产生误判,因此,扩展方法在基本方法的基础上进一步增加校验值长度,具体为:通过传输帧源无线设备的扰码生成器初始状态值隐式地承载校验值,以增加校验值长度。
举例说明,扰码生成器是一个7位的循环移位寄存器,给定7位初始值之后,可输出周期为127的扰码序列。传统机制中,传输帧源无线设备随机选择一个非全0的7位二进制序列作为扰码生成器初始状态值。而在扩展方法中,用校验值中的6位(X1~X6)代替7位随机序列中的6位,剩余1位恒置为1(为了保证初始状态值不全为0)。其它无线设备接收到传输帧后,可反向推导出这7位初始状态值,其中6位是检验值的内容。该方法中通过扰码生成器初始状态值隐式携带6位校验值(X1~X6),加上由服务字段直接携带的9位
(X7~X15),则校验值最多可以包含15bits,其过程如图2所示。
作为一种可能的实施方式,传输帧还包括接收地址字段,接收地址字段包括传输帧的接收地址,字段集还包括接收地址字段。
本实施例中,传输帧的接收地址可以是单播地址,广播地址或组播地址。其中,接收地址为传输帧的目的无线设备地址。
作为一种可能的实施方式,传输帧还包括物理头,物理头包括指示信息,指示信息用于指示传输帧包括校验字段。
举例说明,当物理头中的指示信息的值为1时,表明传输帧包括校验字段,当指示信息的值为0时,表明传输帧不包括校验字段。
S302、发送传输帧,以使接收到传输帧的无线设备根据第一校验值来确定持续时间是否为有效持续时间,并当确定持续时间为有效持续时间时,利用持续时间更新该无线设备的网络分配矢量计时器,其中,第一校验值是第二校验值被携带在校验字段中经过无线信道传输后得到的。具体所述接收到传输帧的无线设备如何根据第一校验值来确定持续时间是否为有效持续时间可以参考前述各实施例的相关内容来理解。
本实施例中,生成传输帧之后,将传输帧发送给接收地址对应的无线设备,在发送的过程中,由于无线信道本身的广播特性,将会被与接收地址对应的无线设备使用同一无线信道的其它无线设备接收到,以便这些无线设备利用第一校验值确定持续时间是否为有效持续时间,当确定持续时间为有效持续时间时,将利用持续时间更新它们的NAV计时器,避免同一时间同一无线信道中出现多个无线设备同时发送数据的情况。
在图3所描述的虚拟载波侦听方法中,生成的传输帧包括校验字段,校验字段中携带有第二校验值,被与接收地址对应的无线设备使用同一无线信道的其它无线设备接收到后,将利用第一校验值验证持续时间是否为有效持续时间,其中,第一校验值是第二校验值被携带在校验字段中经过无线信道传输后得到的,当持续时间为有效持续时间时,将利用持续时间更新它们的NAV计时器,避免同一时间同一无线信道中出现多个无线设备同时发送数据的情况,从而可以提高虚拟载波侦听可靠性。
请参阅图4,图4是本发明实施例公开的一种MAC帧头压缩方法的流程
图。其中,图4所示的MAC帧头压缩方法适用于手机、平板电脑等无线设备。图4所示的MAC帧头压缩方法是从发送侧的角度来描述的。如图4所示,该MAC帧头压缩方法可以包括以下步骤。
S401、构建传输帧,传输帧包括物理头、MAC帧头和帧校验序列,MAC帧头包括传输帧的类型、传输帧的传输方向和地址字段集,物理头包括用于指示传输帧是否为压缩传输帧的指示信息。
本实施例中,IEEE 802.11网络中,存在大量长度较短的短帧,由于短帧中MAC帧头所占传输帧的比例比长帧中MAC帧头所占传输帧的比例大,因此短帧降低了无线信道利用率。提高短帧无线信道利用率的一种方式为:当一个无线设备有多个短帧需要传输时,将这些短帧聚合为长帧进行传输。然而,当这些短帧属于不同用户时,它们之间无法聚合。因此,本实施例中从短帧的MAC帧头着手,通过压缩MAC帧头中的地址字段集来降低MAC帧头所占传输帧的比例。
本实施例中,按照现有规则构建传输帧,传输帧包括物理头、MAC帧头和帧校验序列。MAC帧头包括由至少一个地址字段构成的地址字段集和帧控制字段,其中,帧控制字段包括传输帧的类型和传输帧的传输方向。帧校验序列是采用特定算法、根据MAC帧头和帧体两部分计算获得的。其中,指示信息还可以位于SERVICE域中。SERVICE域位于MAC帧头之前。
S402、根据传输帧的类型和传输帧的传输方向确定地址字段集中能被移除的地址字段。
本实施例中,传输帧的类型可以为控制帧、数据帧、管理帧等,传输帧的传输方向可以为下行帧、上行帧、直连帧等。
本实施例中,控制帧一般包括帧的发送地址和接收地址,或只包括接收地址,这些地址都可被移除,即可被压缩。其中,发送地址为传输帧的源无线设备的地址,接收地址为传输帧的目的无线设备的地址。
本实施例中,数据帧根据控制字段中From DS和To DS取值的不同,可以分为直连帧(From DS=0,To DS=0)、下行帧(From DS=1,To DS=0)、上行帧(From DS=0,To DS=1)和Mesh帧(From DS=1,To DS=1),由于任何Mesh节点间都可自由通信,因此,不压缩Mesh帧的地址;上行帧和下行帧包括接收地址、发送地址和第三地址,接收地址和发送地址可被移除,当帧体
部分为MAC服务数据单元(MAC Service Data Unit,MSDU)时,第三地址为源无线设备地址或目的无线设备地址(当前Wi-Fi网络之外的设备地址),故第三地址不可被压缩;当帧体部分为聚合MSDU(Aggregate MSDU,A-MSDU)时,第三地址为基本服务集标识(Basic Service Set Identifier,BSSID),即接入点地址时,故可以被压缩。怎么知道接收的传输帧帧体部分是MSDU还是A-MSDU呢?事实上,位于MAC帧头中的服务质量(Quality of Service,QoS)控制(Control)字段中存在A-MSDU指示,用于指示帧体部分为A-MSDU或MSDU,其位置在第三地址之后。因此,第三地址存在与否将影响QoS Control字段在帧中的相对位置,即按照QoS控制字段位置,接收方无法先通过该字段获得A-MSDU存在的指示,然后再确定第三地址是否存在。因此,在压缩传输帧时,将QoS控制字段提到所有地址字段之前的位置,以便接收方可以先查看QoS控制字段中的A-MSDU存在的指示,从而可以确定第三地址是否被压缩。QoS控制字段位置移动可以发生在FCS计算之前,也可以发生在FCS计算之后,本实施例不作限定,但其它设备接收到传输帧后也应作相应反操作。直连帧:包括直连的两个站点地址,以及与这两个站点关联的同一接入点的地址,三者均可被压缩。
本实施例中,管理帧包括接收地址、发送地址和第三地址,其中,接收地址和发送地址可被压缩,第三地址可以是BSSID(接入点的地址)或者通配的BSSID,通配的BSSID不能被压缩。因此,管理帧地址字段集压缩有两种方案:A)只压接收地址和发送地址,第三地址始终不压缩;B)当第三地址为BSSID时,三个地址域均被压缩;当第三地址为通配BSSID时,三个地址域都不压缩。由于实际网络中第三地址多为BSSID,因此方案B为优选方案。
本实施例中,当有多个无线设备与本端关联时,为了能够快速地确定发送端的身份、减少试探次数,可采用一些辅助机制。一种基本方案是只压缩其中一种或多种地址,其他地址不压缩,例如:在上行帧或下行帧中,保留接收地址,而压缩发送地址;在直连帧中,保留源站点或目的站点的地址,而压缩另一站点的地址和接入点的地址。此外,还可以在压缩地址字段集的同时,在传输帧的物理头或MAC头中携带发送端设备的短标识,例如关联标识(Association Identifier,AID)、部分关联标识(Partial AID,PAID)等。
本实施例中,若传输帧中包括聚合MAC协议数据单元(Aggregate MAC
protocol data unit,A-MPDU),则将上述地址字段移除规则用于A-MPDU中的所有MAC协议数据单元(MAC protocol data unit,MPDU)。
S403、移除地址字段集中能被移除的地址,以获取压缩的MAC帧头。
S404、设置物理头中的指示信息,使指示信息用于指示传输帧为压缩传输帧,以获取压缩传输帧。
本实施例中,物理头包括SIG字段,其中包括指示信息,用于指示传输帧是否为压缩传输帧。例如,指示信息的值为1时,表示传输帧为压缩传输帧,指示信息的值为0时,表示传输帧为非压缩传输帧。
S405、发送压缩传输帧。
在图4所示的MAC帧头压缩方法中,在发送传输帧之前,先将MAC帧头地址字段集中的部分或全部地址字段移除,以减小传输帧的MAC帧头长度,降低MAC帧头在传输帧中占据的比例,从而提高信道利用率。
请参阅图5,图5是本发明实施例公开的另一种MAC帧头压缩方法的流程图。其中,图5所示的MAC帧头压缩方法适用于手机、平板电脑等无线设备。图5所示的MAC帧头压缩方法是从接收侧的角度来描述的。如图5所示,该MAC帧头压缩方法可以包括以下步骤。
S501、接收传输帧,传输帧包括物理头、MAC帧头和帧校验序列,MAC帧头包括传输帧的类型、传输帧的传输方向和地址字段集,物理头包括指示信息,指示信息用于指示传输帧为压缩传输帧。
本实施例中,IEEE 802.11网络中,存在大量长度较短的短帧,由于短帧中MAC帧头所占传输帧的比例比长帧中MAC帧头所占传输帧的比例大,因此短帧降低了无线信道利用率。提高短帧无线信道利用率的一种方式为:当一个无线设备有多个短帧需要传输时,将这些短帧聚合为长帧进行传输。然而,当这些短帧属于不同用户时,它们之间无法聚合。因此,本实施例中从短帧的MAC帧头着手,通过压缩MAC帧头中的地址字段来降低MAC帧头所占传输帧的比例。其中,指示信息还可以位于SERVICE域中。SERVICE域位于MAC帧头之前。
S502、根据指示信息判断传输帧是否为压缩传输帧。
本实施例中,由于接收到压缩传输帧之后需要进行恢复处理,当传输帧不
是压缩传输帧时,不需要进行恢复处理,因此,在传输帧的物理头中的SIG字段中包括指示信息,用于指示传输帧是否为压缩传输帧。例如,当SIG字段的Compress位为1时,表示传输帧为压缩传输帧,当传输帧SIG字段的Compress位为0时,表示传输帧不是压缩传输帧。其中,传输帧的类型可以为控制帧、数据帧、管理帧等,传输帧的传输方向可以为下行帧、上行帧、直连帧等。
S503、当传输帧为压缩传输帧时,根据传输帧的类型和传输帧的传输方向确定地址字段集中被移除的地址。
本实施例中,接收到传输帧之后,将根据指示信息判断传输帧是否为压缩传输帧,当传输帧为压缩传输帧时,利用传输帧的类型和传输帧的传输方向确定地址字段集中被移除的地址。
S504、添加被移除的地址,以获取解压的传输帧。
传输帧中接收地址、发送地址、第三地址中的任何一个或多个都可能被压缩。此处以同时压缩接收地址和发送地址为例,说明接收端如何恢复被压缩的地址字段。其它情况采用类似方法处理,此处不再赘述。
当被移除的地址由传输帧的接收地址和传输帧的发送地址组成时,添加被移除的地址,以获取解压的传输帧可以包括以下步骤。
A1、将与本端关联的无线设备的地址作为传输帧的发送地址,将本端的地址作为传输帧的接收地址,以获取包括被移除地址的传输帧。
A2、计算包括被移除地址的传输帧的目标帧校验序列。
A3、判断目标帧校验序列与传输帧包括的帧校验序列是否匹配,当目标帧校验序列与该帧校验序列匹配时,将包括被移除地址的传输帧作为解压的传输帧。
本实施例中,当被移除的地址由传输帧的发送设备地址和传输帧的接收地址组成时,假设此时与本端关联的无线设备的地址为传输帧的发送地址、本端的地址为传输帧的接收地址,以获取包括被移除地址的传输帧,之后利用循环冗余算法计算包括被移除地址的传输帧的目标帧校验序列,之后判断目标帧校验序列与传输帧包括的帧校验序列是否匹配,当目标帧校验序列与传输帧包括的帧校验序列匹配时,则表明假设成立,传输帧是由关联的无线设备发送给本
端的传输帧,将包括被移除地址的传输帧作为解压的传输帧;当目标帧校验序列与该帧校验序列不匹配时,则表明假设不成立,传输帧不是关联的无线设备发送给本端的传输帧。当与本端相连的无线设备为多个无线设备时,将执行多次上述操作,直到匹配成功或尝试完所有与本端相连的无线设备为止。
本实施例中,当有多个无线设备与本端关联时,为了能够快速地确定发送端的身份、减少试探次数,可采用一些辅助机制。一种基本方案是只压缩其中一种或多种地址,其他地址不压缩,例如:在上行帧或下行帧中,保留接收地址,而压缩发送地址;在直连帧中,保留源站点或目的站点的地址,而压缩另一站点的地址和接入点的地址。此外,还可以在压缩地址字段集的同时,在传输帧的物理头或MAC头中携带发送端设备的短标识,例如AID、PAID等。
在图5所示的MAC帧头压缩方法中,当传输帧为压缩帧时,MAC帧头地址字段集中的部分或全部地址被移除,传输帧的MAC帧头的长度减小,使MAC帧头在传输帧中占据的比例降低,从而提高信道利用率。
请参阅图6,图6是本发明实施例公开的一种无线设备的结构图。其中,该无线设备可以为手机、平板电脑等,本实施例不作限定。如图6所示,该无线设备600可以包括:
接收单元601,用于接收传输帧,传输帧包括服务字段和持续时间字段,其中,服务字段包括校验字段,校验字段中携带有第一校验值,第一校验值是第二校验值被携带在校验字段中经过无线信道传输后得到的,第二校验值是发送传输帧的无线设备生成传输帧时根据字段集按预定算法计算得到的;其中,字段集是传输帧包括的字段中的部分字段,字段集包括持续时间字段;持续时间字段包括持续时间;
判断单元602,用于根据接收单元601接收的传输帧包括的第一校验值来确定持续时间是否为有效持续时间;
更新单元603,用于当判断单元602确定持续时间为有效持续时间时,利用接收单元601接收的传输帧包括的持续时间更新该无线设备的NAV计时器。
具体地,更新单元603,具体用于当判断单元602确定持续时间为有效持续时间时,利用持续时间更新该无线设备的NAV计时器。
作为一种可能的实施方式,判断单元602具体用于:
根据字段集按预定算法计算得到第三校验值;
当第一校验值与第三校验值匹配时,确定持续时间为有效持续时间。
作为一种可能的实施方式,传输帧还包括接收地址字段,接收地址字段包括传输帧的接收地址,字段集还包括接收地址字段;
更新单元603,具体用于当根据第一校验值确定持续时间为有效持续时间、接收地址为有效接收地址时,若接收地址与该无线设备的地址不匹配,且持续时间大于该无线设备的网络分配矢量计时器的时间时,则利用持续时间更新所该无线设备的网络分配矢量计时器。
作为一种可能的实施方式,传输帧还包括物理头,物理头包括指示信息,指示信息用于指示传输帧包括校验字段。
现有方法中,无线设备只有当接收地址为有效地址且接收地址与本端的地址不匹配时,若传输帧为有效帧,才利用持续时间更新本端的NAV计时器;当接收的传输帧为无效帧时,该无线设备无法根据该持续时间设置NAV计时器,就会在该无线信道发送数据,以致在同一时间同一无线信道中出现多个无线设备同时发送数据,降低了虚拟载波侦听可靠性。在本发明实施例提供的虚拟载波侦听方法中,通过在传输帧的服务字段里包括校验字段,根据该校验字段中携带的第一校验值来确定接收的传输帧包括的持续时间是否为有效持续时间、接收的传输帧包括的接收地址是否为有效接收地址,不论接收的传输帧是否为有效帧,即不需要对传输帧整个帧利用FCS判断该传输帧是否为有效帧,只需要对传输帧里包括的接收地址和持续时间进行校验,当接收地址为有效接收地址,且接收地址与本端的地址不匹配时,确定传输帧里包括的持续时间为有效持续时间,就可以利用持续时间来更新本端的NAV计时器,以使本端在NAV计时器的时间递减为零之前不发送数据,避免同一时间同一无线信道中出现多个无线设备同时发送数据的情况,从而可以提高虚拟载波侦听可靠性。
请参阅图7,图7是本发明实施例公开的另一种无线设备的结构图。其中,该无线设备可以为手机、平板电脑等,本实施例不作限定。如图7所示,该无
线设备700可以包括处理器701、存储器702、输入装置703和输出装置704。处理器701与存储器702、处理器701与输入装置703、处理器701与输出装置704可以通过总线或其它方式连接,本实施例中以总线连接为例。其中:
输入装置703,用于接收传输帧并发送给处理器701,传输帧包括服务字段和持续时间字段,其中,服务字段包括校验字段,校验字段中携带有第一校验值,第一校验值是第二校验值被携带在校验字段中经过无线信道传输后得到的,第二校验值是发送传输帧的无线设备生成传输帧时根据字段集按预定算法计算得到的;其中,字段集是传输帧包括的字段中的部分字段,字段集包括持续时间字段;持续时间字段包括持续时间;
存储器702中存储有一组程序代码,处理器701用于调用存储器702中存储的程序代码执行以下操作:
根据第一校验值来确定持续时间是否为有效持续时间;
当确定持续时间为有效持续时间时,利用持续时间更新该无线设备的NAV计时器。
作为一种可能的实施方式,输出装置704,用于发送消息。
作为一种可能的实施方式,处理器701用于根据第一校验值来确定持续时间是否为有效持续时间的方式具体为:
处理器701用于根据字段集按预定算法计算得到第三校验值;
当第一校验值与第三校验值匹配时,确定持续时间为有效持续时间。
作为一种可能的实施方式,传输帧还包括接收地址字段,接收地址字段包括传输帧的接收地址,字段集还包括接收地址字段;
处理器701用于当确定持续时间为有效持续时间时,利用持续时间更新该无线设备的网络分配矢量计时器的方式具体为:
处理器701用于当根据第一校验值确定持续时间为有效持续时间、接收地址为有效接收地址时,若接收地址与该无线设备的地址不匹配,且持续时间大于该无线设备的网络分配矢量计时器的时间,则利用持续时间更新该无线设备的网络分配矢量计时器。
作为一种可能的实施方式,传输帧还包括物理头,物理头包括指示信息,指示信息用于指示传输帧包括校验字段。
现有方法中,无线设备只有当接收地址为有效地址且接收地址与本端的地址不匹配时,若传输帧为有效帧,才利用持续时间更新本端的NAV计时器;当接收的传输帧为无效帧时,该无线设备无法根据该持续时间设置NAV计时器,就会在该无线信道发送数据,以致在同一时间同一无线信道中出现多个无线设备同时发送数据,降低了虚拟载波侦听可靠性。在本发明实施例提供的虚拟载波侦听方法中,通过在传输帧的服务字段里包括校验字段,根据该校验字段中携带的第一校验值来确定接收的传输帧包括的持续时间是否为有效持续时间、接收的传输帧包括的接收地址是否为有效接收地址,不论接收的传输帧是否为有效帧,即不需要对传输帧整个帧利用FCS判断该传输帧是否为有效帧,只需要对传输帧里包括的接收地址和持续时间进行校验,当接收地址为有效接收地址,且接收地址与本端的地址不匹配时,确定传输帧里包括的持续时间为有效持续时间,就可以利用持续时间来更新本端的NAV计时器,以使本端在NAV计时器的时间递减为零之前不发送数据,避免同一时间同一无线信道中出现多个无线设备同时发送数据的情况,从而可以提高虚拟载波侦听可靠性。
请参阅图8,图8是本发明实施例公开的又一种无线设备的结构图。其中,该无线设备可以为手机、平板电脑等,本实施例不作限定。如图8所示,该无线设备800可以包括:
生成单元801,用于生成传输帧,传输帧包括服务字段和持续时间字段,其中,服务字段包括校验字段,校验字段中携带有第二校验值,第二校验值根据字段集按预定算法计算得到,字段集是传输帧包括的字段中的部分字段,字段集包括持续时间字段,持续时间字段包括持续时间;
发送单元802,用于发送生成单元801生成的传输帧,以使接收到传输帧的目标无线设备根据第一校验值来确定持续时间是否为有效持续时间,并当确定持续时间为有效持续时间时,利用持续时间更新该目标无线设备的网络分配矢量计时器,其中,第一校验值是第二校验值被携带在校验字段中经过无线信道传输后得到的。
作为一种可能的实施方式,传输帧还包括接收地址字段,接收地址字段包括传输帧的接收地址,字段集还包括接收地址字段。
作为一种可能的实施方式,传输帧还包括物理头,物理头包括指示信息,指示信息用于指示传输帧包括校验字段。
在图8所描述的无线设备中,生成的传输帧包括校验字段,校验字段中携带有第二校验值,被与接收地址对应的无线设备使用同一无线信道的其它无线设备接收到后,将利用第一校验值验证持续时间是否为有效持续时间,其中,第一校验值是第二校验值被携带在校验字段中经过无线信道传输后得到的,当持续时间为有效持续时间时,将利用持续时间更新它们的NAV计时器,避免同一时间同一无线信道中出现多个无线设备同时发送数据的情况,从而可以提高虚拟载波侦听可靠性。
请参阅图9,图9是本发明实施例公开的又一种无线设备的结构图。其中,该无线设备可以为手机、平板电脑等,本实施例不作限定。如图9所示,该无线设备900可以包括处理器901、存储器902、输出装置903和输入装置904。处理器901与存储器902、处理器901与输入装置903、处理器901与输入装置904可以通过总线或其它方式连接,本实施例中以总线连接为例。其中:
存储器902中存储有一组程序代码,处理器901用于调用存储器902中存储的程序代码执行以下操作:
生成传输帧,传输帧包括服务字段和持续时间字段,其中,服务字段包括校验字段,校验字段中携带有第二校验值,第二校验值根据字段集按预定算法计算得到,字段集是传输帧包括的字段中的部分字段,字段集包括持续时间字段,持续时间字段包括持续时间;
输出装置903,用于发送传输帧,以使接收到传输帧的目标无线设备根据第一校验值来确定持续时间是否为有效持续时间,并当确定持续时间为有效持续时间时,利用持续时间更新该目标无线设备的网络分配矢量计时器,其中,第一校验值是第二校验值被携带在校验字段中经过无线信道传输后得到的。
作为一种可能的实施方式,该无线设备900还可以包括输入装置904,用于接收消息。
作为一种可能的实施方式,传输帧还包括接收地址字段,接收地址字段包括传输帧的接收地址,字段集还包括接收地址字段。
作为一种可能的实施方式,传输帧还包括物理头,物理头包括指示信息,指示信息用于指示传输帧包括校验字段。
在图9所示的无线设备中,生成的传输帧包括校验字段,校验字段中携带有第二校验值,被与接收地址对应的无线设备使用同一无线信道的其它无线设备接收到后,将利用第一校验值验证持续时间是否为有效持续时间,其中,第一校验值是第二校验值被携带在校验字段中经过无线信道传输后得到的,当持续时间为有效持续时间时,将利用持续时间更新它们的NAV计时器,避免同一时间同一无线信道中出现多个无线设备同时发送数据的情况,从而可以提高虚拟载波侦听可靠性。
请参阅图10,图10是本发明实施例公开的又一种无线设备的结构图。其中,该无线设备可以为手机、平板电脑等,本实施例不作限定。如图10所示,该无线设备1000可以包括:
构建单元1001,用于构建传输帧,传输帧包括物理头、MAC帧头和帧校验序列,MAC帧头包括传输帧的类型、传输帧的传输方向和地址字段集,物理头包括用于指示传输帧是否为压缩传输帧的指示信息;
确定单元1002,用于根据构建单元1001构建的传输帧的类型和构建单元1001构建的传输帧的传输方向确定地址字段集中能被移除的地址字段;
移除单元1003,用于移除构建单元1001构建的地址字段集中确定单元1002确定的能被移除的地址,以获取压缩的MAC帧头;
获取单元1004,用于设置构建单元1001构建的传输帧包括的物理头中的指示信息,使指示信息用于指示传输帧为压缩传输帧,以获取压缩传输帧;
发送单元1005,发送获取单元1004获取的压缩传输帧。
具体地,移除单元1003,用于移除构建单元1001构建的地址字段集中确定单元1002确定的能被移除的地址,以获取压缩的MAC帧头,触发获取单元1004设置构建单元1001构建的传输帧包括的物理头中的指示信息,使指示信息用于指示传输帧为压缩传输帧,以获取压缩传输帧
在图10所示的无线设备中,在发送传输帧之前,先将MAC帧头地址字段集中的部分或全部地址字段移除,以减小传输帧的MAC帧头长度,降低MAC帧头在传输帧中占据的比例,从而提高信道利用率。
请参阅图11,图11是本发明实施例公开的又一种无线设备的结构图。其中,该无线设备可以为手机、平板电脑等,本实施例不作限定。如图11所示,该无线设备1100可以包括处理器1101、存储器1102、输出装置1103和输入装置1104。处理器1101与存储器1102、处理器1101与输出装置1103、处理器1101与输入装置1104可以通过总线或其它方式连接,本实施例中以总线连接为例。其中:
存储器1102中存储有一组程序代码,处理器1101用于调用存储器1102中存储的程序代码执行以下操作:
构建传输帧,传输帧包括物理头、MAC帧头和帧校验序列,MAC帧头包括传输帧的类型、传输帧的传输方向和地址字段集,物理头包括用于指示传输帧是否为压缩传输帧的指示信息;
根据传输帧的类型和传输帧的传输方向确定地址字段集中能被移除的地址字段;
移除地址字段集中能被移除的地址,以获取压缩的MAC帧头;
设置物理头中的指示信息,使指示信息用于指示传输帧为压缩传输帧,以获取压缩传输帧;
输出装置1103,用于发送压缩传输帧。
作为一种可能的实施方式,输入装置1104,用于接收消息。
在图11所示的无线设备中,在发送传输帧之前,先将MAC帧头地址字段集中的部分或全部地址字段移除,以减小传输帧的MAC帧头长度,降低MAC帧头在传输帧中占据的比例,从而提高信道利用率。
请参阅图12,图12是本发明实施例公开的又一种无线设备的结构图。其中,该无线设备可以为手机、平板电脑等,本实施例不作限定。如图12所示,该无线设备1200可以包括:
接收单元1201,用于接收传输帧,传输帧包括物理头、MAC帧头和帧校验序列,MAC帧头包括传输帧的类型、传输帧的传输方向和地址字段集,物理头包括指示信息,指示信息用于指示传输帧为压缩传输帧;
判断单元1202,用于根据接收单元1201接收的指示信息判断传输帧是否
为压缩传输帧;
确定单元1203,用于当判断单元1202的判断结果为是时,利用接收单元1201获取的传输帧的类型和接收单元1201获取的传输帧的传输方向确定字段集中被移除的地址;
添加单元1204,用于添加确定单元1203确定的被移除的地址,以获取解压的传输帧。
作为一种可能的实施方式,当被移除的地址由传输帧的接收地址和传输帧的发送地址组成时,添加单元1204可以包括:
地址获取子单元,用于将与该无线设备关联的目标无线设备的地址作为传输帧的发送地址,将该无线设备的地址作为传输帧的接收地址,以获取包括被移除地址的传输帧。
序列获取子单元,用于计算地址获取子单元获取的包括被移除地址的传输帧的目标帧校验序列。
判断子单元,用于判断序列获取子单元获取的目标帧校验序列与接收单元1201接收的传输帧包括的帧校验序列是否匹配,当判断子单元的判断结果为是时,将包括被移除地址的传输帧作为解压的传输帧。
在图12所示的无线设备中,当传输帧为压缩帧时,MAC帧头地址字段集中的部分或全部地址字段被移除,传输帧的MAC帧头的长度减小,使MAC帧头在传输帧中占据的比例降低,从而提高信道利用率。
请参阅图13,图13是本发明实施例公开的又一种无线设备的结构图。其中,该无线设备可以为手机、平板电脑等,本实施例不作限定。如图13所示,该无线设备1300可以包括处理器1301、存储器1302、输入装置1303和输出装置1304。处理器1301与存储器1302、处理器1301与输入装置1303、处理器1301与输出装置1304可以通过总线或其它方式连接,本实施例以总线连接为例。其中:
输入装置1303,用于接收传输帧,传输帧包括物理头、MAC帧头和帧校验序列,MAC帧头包括传输帧的类型、传输帧的传输方向和地址字段集,物理头包括指示信息,指示信息用于指示传输帧为压缩传输帧;
存储器1302中存储有一组程序代码,处理器1301用于调用存储器1302
中存储的程序代码执行以下操作:
根据指示信息判断传输帧是否为压缩传输帧;
当传输帧为压缩传输帧时,根据传输帧的类型和传输帧的传输方向确定地址字段集中被移除的地址;
添加被移除的地址,以获取解压的传输帧。
作为一种可能的实施方式,输出装置1304,用于发送消息。
作为一种可能的实施方式,当被移除的地址由传输帧的接收地址和传输帧的发送地址组成时,处理器1301添加被移除的地址,以获取解压的传输帧的方式具体为:
将与该无线设备关联的目标无线设备的地址作为传输帧的发送地址,将该无线设备的地址作为传输帧的接收地址,以获取包括被移除地址的传输帧;
计算包括被移除地址的传输帧的目标帧校验序列;
判断目标帧校验序列与传输帧包括的帧校验序列是否匹配,若目标帧校验序列与该帧校验序列匹配,将包括被移除地址的传输帧作为解压的传输帧。
在图13所示的无线设备中,当传输帧为压缩帧时,MAC帧头地址字段集中的部分或全部地址被移除,传输帧的MAC帧头的长度减小,使MAC帧头在传输帧中占据的比例降低,从而提高信道利用率。
一个实施例中,本发明实施例进一步公开一种计算机存储介质,该计算机存储介质存储有计算机程序,当计算机存储介质中的计算机程序被读取到计算机时,能够使得计算机完成本发明实施例公开的虚拟载波侦听方法的全部步骤。
需要说明的是,对于前述的各个方法实施例,为了简单描述,故将其都表述为一系列的动作组合,但是本领域技术人员应该知悉,本发明并不受所描述的动作顺序的限制,因为依据本发明,某一些步骤可以采用其他顺序或者同时进行。其次,本领域技术人员也应该知悉,说明书中所描述的实施例均属于优选实施例,所涉及的动作和模块并不一定是本发明所必须的。
本领域普通技术人员可以理解上述实施例的各种方法中的全部或部分步骤是可以通过程序来指令相关的硬件来完成,该程序可以存储于一计算机可读
存储介质中,存储介质可以包括:闪存盘、只读存储器(Read-Only Memory,ROM)、随机存取器(Random Access Memory,RAM)、磁盘或光盘等。
以上对本发明实施例所提供的虚拟载波侦听方法及装置进行了详细介绍,本文中应用了具体个例对本发明的原理及实施方式进行了阐述,以上实施例的说明只是用于帮助理解本发明的方法及其核心思想;同时,对于本领域的一般技术人员,依据本发明的思想,在具体实施方式及应用范围上均会有改变之处,综上所述,本说明书内容不应理解为对本发明的限制。
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- 一种虚拟载波侦听方法,其特征在于,包括:接收传输帧,所述传输帧包括服务字段和持续时间字段,其中,所述服务字段包括校验字段,所述校验字段中携带有第一校验值,所述第一校验值是第二校验值被携带在所述校验字段中经过无线信道传输后得到的,所述第二校验值是发送所述传输帧的无线设备生成所述传输帧时根据字段集按预定算法计算得到的;其中,所述字段集是所述传输帧包括的字段中的部分字段,所述字段集包括所述持续时间字段;所述持续时间字段包括持续时间;根据所述第一校验值来确定所述持续时间是否为有效持续时间;当确定所述持续时间为有效持续时间时,利用所述持续时间更新本端的网络分配矢量计时器。
- 如权利要求1所述的方法,其特征在于,所述根据所述第一校验值来确定所述持续时间是否为有效持续时间,包括:根据所述字段集按所述预定算法计算得到第三校验值;当所述第一校验值与所述第三校验值匹配时,确定所述持续时间为有效持续时间。
- 如权利要求1或2所述的方法,其特征在于,所述传输帧还包括接收地址字段,所述接收地址字段包括所述传输帧的接收地址,所述字段集还包括所述接收地址字段;所述当确定所述持续时间为有效持续时间时,利用所述持续时间更新本端的网络分配矢量计时器包括:当根据所述第一校验值确定所述持续时间为有效持续时间、所述接收地址为有效接收地址时,若所述接收地址与本端的地址不匹配,且所述持续时间大于本端的网络分配矢量计时器的时间,则利用所述持续时间更新本端的网络分配矢量计时器。
- 如权利要求1-3任一所述的方法,其特征在于,所述传输帧还包括物理 头,所述物理头包括指示信息,所述指示信息用于指示所述传输帧包括所述校验字段。
- 一种虚拟载波侦听方法,其特征在于,包括:生成传输帧,所述传输帧包括服务字段和持续时间字段,其中,所述服务字段包括校验字段,所述校验字段中携带有第二校验值,所述第二校验值根据字段集按预定算法计算得到,所述字段集是所述传输帧包括的字段中的部分字段,所述字段集包括所述持续时间字段,所述持续时间字段包括持续时间;发送所述传输帧,以使接收到所述传输帧的无线设备根据第一校验值来确定所述持续时间是否为有效持续时间,并当确定所述持续时间为有效持续时间时,利用所述持续时间更新该无线设备的网络分配矢量计时器,其中,所述第一校验值是所述第二校验值被携带在所述校验字段中经过无线信道传输后得到的。
- 如权利要求5所述的方法,其特征在于,所述传输帧还包括接收地址字段,所述接收地址字段包括所述传输帧的接收地址,所述字段集还包括所述接收地址字段。
- 如权利要求5或6所述的方法,其特征在于,所述传输帧还包括物理头,所述物理头包括指示信息,所述指示信息用于指示所述传输帧包括所述校验字段。
- 一种无线设备,其特征在于,包括:接收单元,用于接收传输帧,所述传输帧包括服务字段和持续时间字段,其中,所述服务字段包括校验字段,所述校验字段中携带有第一校验值,所述第一校验值是第二校验值被携带在所述校验字段中经过无线信道传输后得到的,所述第二校验值是发送所述传输帧的无线设备生成所述传输帧时根据字段集按预定算法计算得到的;其中,所述字段集是所述传输帧包括的字段中的部分字段,所述字段集包括所述持续时间字段;所述持续时间字段包括持续时间;判断单元,用于根据所述接收单元接收的传输帧包括的第一校验值来确定所述持续时间是否为有效持续时间;更新单元,用于当所述判断单元确定所述持续时间为有效持续时间时,利用所述持续时间更新所述无线设备的网络分配矢量计时器。
- 如权利要求8所述的无线设备,其特征在于,所述判断单元具体用于:根据所述字段集按所述预定算法计算得到第三校验值;当所述第一校验值与所述第三校验值匹配时,确定所述持续时间为有效持续时间。
- 如权利要求8或9所述的无线设备,其特征在于,所述传输帧还包括接收地址字段,所述接收地址字段包括所述传输帧的接收地址,所述字段集还包括所述接收地址字段;所述更新单元,具体用于当根据所述第一校验值确定所述持续时间为有效持续时间、所述接收地址为有效接收地址时,若所述接收地址与所述无线设备的地址不匹配,且所述持续时间大于所述无线设备的网络分配矢量计时器的时间时,则利用所述持续时间更新所述无线设备的网络分配矢量计时器。
- 如权利要求8-10任一所述的无线设备,其特征在于,所述传输帧还包括物理头,所述物理头包括指示信息,所述指示信息用于指示所述传输帧包括所述校验字段。
- 一种无线设备,其特征在于,包括处理器、存储器和输入装置,其中:所述输入装置,用于接收传输帧并发送给所述处理器,所述传输帧包括服务字段和持续时间字段,其中,所述服务字段包括校验字段,所述校验字段中携带有第一校验值,所述第一校验值是第二校验值被携带在所述校验字段中经过无线信道传输后得到的,所述第二校验值是发送所述传输帧的无线设备生成所述传输帧时根据字段集按预定算法计算得到的;其中,所述字段集是所述传输帧包括的字段中的部分字段,所述字段集包括所述持续时间字段;所述持续 时间字段包括持续时间;所述存储器中存储有一组程序代码,所述处理器用于调用所述存储器中存储的程序代码执行以下操作:根据所述第一校验值来确定所述持续时间是否为有效持续时间;当确定所述持续时间为有效持续时间时,利用所述持续时间更新所述无线设备的网络分配矢量计时器。
- 如权利要求12所述的无线设备,其特征在于,所述处理器用于根据所述第一校验值来确定所述持续时间是否为有效持续时间的方式具体为:所述处理器用于根据所述字段集按所述预定算法计算得到第三校验值;当所述第一校验值与所述第三校验值匹配时,确定所述持续时间为有效持续时间。
- 如权利要求12或13所述的无线设备,其特征在于,所述传输帧还包括接收地址字段,所述接收地址字段包括所述传输帧的接收地址,所述字段集还包括所述接收地址字段;所述处理器用于当确定所述持续时间为有效持续时间时,利用所述持续时间更新所述无线设备的网络分配矢量计时器的方式具体为:所述处理器用于当根据所述第一校验值确定所述持续时间为有效持续时间、所述接收地址为有效接收地址时,若所述接收地址与所述无线设备的地址不匹配,且所述持续时间大于所述无线设备的网络分配矢量计时器的时间,则利用所述持续时间更新所述无线设备的网络分配矢量计时器。
- 如权利要求12-14任一所述的无线设备,其特征在于,所述传输帧还包括物理头,所述物理头包括指示信息,所述指示信息用于指示所述传输帧包括所述校验字段。
- 一种无线设备,其特征在于,包括:生成单元,用于生成传输帧,所述传输帧包括服务字段和持续时间字段, 其中,所述服务字段包括校验字段,所述校验字段中携带有第二校验值,所述第二校验值根据字段集按预定算法计算得到,所述字段集是所述传输帧包括的字段中的部分字段,所述字段集包括所述持续时间字段,所述持续时间字段包括持续时间;发送单元,用于发送所述生成单元生成的传输帧,以使接收到所述传输帧的目标无线设备根据第一校验值来确定所述持续时间是否为有效持续时间,并当确定所述持续时间为有效持续时间时,利用所述持续时间更新该目标无线设备的网络分配矢量计时器,其中,所述第一校验值是所述第二校验值被携带在所述校验字段中经过无线信道传输后得到的。
- 如权利要求16所述的无线设备,其特征在于,所述传输帧还包括接收地址字段,所述接收地址字段包括所述传输帧的接收地址,所述字段集还包括所述接收地址字段。
- 如权利要求16或17所述的无线设备,其特征在于,所述传输帧还包括物理头,所述物理头包括指示信息,所述指示信息用于指示所述传输帧包括所述校验字段。
- 一种无线设备,其特征在于,包括处理器、存储器和输出装置,其中:所述存储器中存储有一组程序代码,所述处理器用于调用所述存储器中存储的程序代码执行以下操作:生成传输帧,所述传输帧包括服务字段和持续时间字段,其中,所述服务字段包括校验字段,所述校验字段中携带有第二校验值,所述第二校验值根据字段集按预定算法计算得到,所述字段集是所述传输帧包括的字段中的部分字段,所述字段集包括所述持续时间字段,所述持续时间字段包括持续时间;所述输出装置,用于发送所述传输帧,以使接收到所述传输帧的目标无线设备根据第一校验值来确定所述持续时间是否为有效持续时间,并当确定所述持续时间为有效持续时间时,利用所述持续时间更新该目标无线设备的网络分配矢量计时器,其中,所述第一校验值是所述第二校验值被携带在所述校验字 段中经过无线信道传输后得到的。
- 如权利要求19所述的无线设备,其特征在于,所述传输帧还包括接收地址字段,所述接收地址字段包括所述传输帧的接收地址,所述字段集还包括所述接收地址字段。
- 如权利要求19或20所述的无线设备,其特征在于,所述传输帧还包括物理头,所述物理头包括指示信息,所述指示信息用于指示所述传输帧包括所述校验字段。
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WO2022222843A1 (zh) * | 2021-04-20 | 2022-10-27 | 华为技术有限公司 | 扰码序列的初始化状态的确定方法和装置 |
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