Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B7/00—Radio transmission systems, i.e. using radiation field
  • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
  • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
  • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
  • H04B7/0602—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using antenna switching
  • H04B7/0608—Antenna selection according to transmission parameters
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B17/00—Monitoring; Testing
  • H04B17/10—Monitoring; Testing of transmitters
  • H04B17/101—Monitoring; Testing of transmitters for measurement of specific parameters of the transmitter or components thereof
  • H04B17/104—Monitoring; Testing of transmitters for measurement of specific parameters of the transmitter or components thereof of other parameters, e.g. DC offset, delay or propagation times

Definitions

• the WLAN Wireless Local Access Network
• APs Access Points
• Stations wireless terminals
• interference will occur between different APs and Stations; besides, signals emitted by devices such as microwave ovens and Bluetooth also have interference to the WLAN system, causing the throughput of WLAN unstable.
• Manufacturers of the WLAN devices start to implement the Beamforming technology in the 802.11 ⁇ protocol, on the other hand, they start to use the switched beam technology, which two technologies both belong to the technology of smart antennae. The switched beam technology is applied more widely at the present stage.
• the switched beam technology depends upon an antenna array composed of a plurality of omnidirectional/directional antennae in an AP or other device. Each data transmission rate may try to use a different antenna in the antenna array. Therefore the AP may store some historical statistics about each data transmission rate and each antenna. It may be desirable to use a relatively low data transmission rate in a poor environment (e.g. one with a high level of background interference) and a relatively higher data transmission rate in a better environment (with less background interference). In the switched beam technology, when a relatively poor environment becomes better (e.g. background interference reduces), an AP may attempt to change from the relatively low data transmission rate used currently to a higher data transmission rate. BRIEF DESCRIPTION OF THE DRAWINGS
• Fig. 1 is a schematic drawing of data transmission rate detection process according to an example
• Fig. 2 is a schematic drawing of a database for recording historical statistics information about combination of each data transmission rate and each antenna according to an example
• Fig. 3 is a schematic drawing for recording time at which previous data transmission rate detection is carried out by each antenna according to an example
• Fig. 4 is a flow chart of a data transmission rate detection method for use with smart antennae provided according to an example
• Fig. 5 is a structural diagram of a data transmission rate detection device for use with smart antennae provided according to an example. DETAILED DESCRIPTION
• the term “includes” means includes but not limited to, the term “including” means including but not limited to.
• the term “based on” means based at least in part on.
• the terms “a” and “an” are intended to denote at least one of a particular element.
• an AP may wish to change to a higher data transmission rate.
• the AP may do this by first detecting if the higher data transmission rate is available. This process of detecting if another data transmission rate is available is known as 'data transmission rate detection' or 'detecting a data transmission rate' .
• 'data transmission rate detection' or 'detecting a data transmission rate' .
• an AP performs data transmission rate detection for a higher data transmission rate, by using a selected antenna to check if it is possible to maintain a connection with wireless client devices joined to said AP at the higher data transmission rate. If it is possible, then the AP may switch to the higher data transmission rate.
• an AP may select one antennae to perform the data transmission rate detection.
• the AP selects the antenna which has the lowest packet loss rate at the current (relatively lower) data transmission rate.
• the antenna with the lowest packet loss rate may be determined from the historical statistics information stored by the access point.
• the antenna with the lowest packet loss rate at the current data transmission rate may not necessarily be the best antenna to carry out the rate detection for the new (e.g. higher) data transmission rate.
• the present disclosure proposes selecting an antenna to perform the data transmission rate detection for a first (e.g. higher) data transmission rate based on the packet loss rate at a second (e.g. current) data transmission rate of the antenna and the time elapsed since the antenna last performed data transmission rate detection at the first data transmission rate.
• the system may select an antenna more likely to succeed at the data transmission rate detection and adapt more quickly to changing environmental conditions.
• FIG. 1 is a schematic drawing of data transmission rate detection process according to an example.
• said process comprises determining by an AP device that a timer for data transmission rate detection is time up.
• said process comprises acquiring by the AP device a higher data transmission rate to be detected.
• said process comprises selecting by the AP device a suitable antenna for the higher data transmission rate which is to carry out the higher data transmission rate detection.
• said process comprises carrying out the higher data transmission rate detection by the AP device by sending messages at the higher data transmission rate via the selected antenna.
• packet loss rate statistics information needs to be recorded in the database of the AP device.
• Fig. 2 shows a schematic drawing of the database to be used when selecting the suitable antenna, said database records historical statistics information about combination of each data transmission rate and each antenna, i.e. the packet loss rate statistics information obtained after using combination of each data transmission rate and each antenna.
• the current data transmission rate is 120 Mb/s(Megabyte per second)
• the database may only record a specified number of antennae having the lowest packet loss rate, which are ordered according to the packet loss rate from low to high; or it may record all antennae which are ordered according to the packet loss rate from low to high).
• the AP device When the current data transmission rate is 120 Mb/s, if it is needed to detect a data transmission rate of 180 Mb/s that is higher than 120 Mb/s (these two data transmission rate values are recorded in said database and are two adjacent data transmission rate values), the AP device needs to select one antenna from the five antennae which is to carry out the data transmission rate detection.
• the existing data transmission rate detection method is to directly use antenna No.10 which has the minimum packet loss rate.
• the disclosure provides a data transmission rate detection method for use with smart antennae, which is applied to a wireless local area network and is used for carrying out data transmission rate detection for higher data transmission rates.
• the current data transmission rate is a specified second data transmission rate (i.e. the rate at which messages are sent at present), and the higher data transmission rate to be detected is a specified first data transmission rate, the specified first data transmission rate is higher than the specified second data transmission rate, and the specified first data transmission rate value and specified second data transmission rate value are recorded in said database and are two adjacent data transmission rate values.
• the AP device e.g. the database of the AP device
• said time of carrying out the data transmission rate detection is a detection time with respect to the specified first data transmission rate
• the AP device records the time at which the previous data transmission rate detection on 180 Mb/s is carried out by each antenna, as shown in Fig. 3, which is a schematic drawing 300 for recording time at which the previous data transmission rate detection for the specified first data transmission rate was carried out by each antenna.
• the packet loss rate information (as shown in Fig. 2) obtained by combination of each data transmission rate and each antenna and the time of carrying out the previous data transmission rate detection by each antenna (as shown in Fig. 3) are recorded, wherein unit of said time is ms (millisecond) and said time starts since the AP device was switched on.
• Fig. 4 shows a flow chart of a data transmission rate detection method for use with smart antennae according to an example.
• said method comprises determining, by the AP device, that data transmission rate detection needs to be carried out for a specified first data transmission rate. Wherein, when the timer for the data transmission rate detection is time up, the AP device determines that data transmission rate detection needs to be carried out for the specified first data transmission rate.
• the specified first data transmission rate is a data transmission rate higher than the current data transmission rate (i.e. the specified second data transmission rate). For example, when the current data transmission rate (i.e. the specified second data transmission rate) is 120 Mb/s, the AP device determines that data transmission rate detection needs to be carried out for a higher first data transmission rate (e.g. 180 Mb/s).
• said method comprises selecting, by the AP device, an antenna which is to carry out data transmission rate detection.
• the selection is on the basis of a packet loss rate of each antenna at the specified second data transmission rate and a time interval between the time of carrying out the previous data transmission rate detection for the specified first data transmission rate by each antenna and the current time.
• the specified first data transmission rate is greater than the specified second data transmission rate, and the specified first data transmission rate value and the specified second data transmission rate value are recorded in the database and are two adjacent data transmission rate values.
• the AP device needs to acquire the minimum packet loss rate at the specified second data transmission rate, and select, among the antennae for which said time interval is greater than a preset time threshold and the difference between the packet loss rate at said specified second data transmission rate and said minimum packet loss rate does not exceed a preset packet loss rate threshold, an antenna having the minimum packet loss rate at the specified second data transmission rate as the antenna which is to carry out data transmission rate detection.
• the preset packet loss rate threshold is to set according to a random packet loss rate produced when sending packets by an air interface. For example, considering that sending packets by an air interface has a random packet loss rate of 12% in practice, so said preset packet loss rate threshold can be set to be 12%.
• the preset time threshold is set according to the total number of the antennae which are to carry out data transmission rate detection and/or said time interval. For example, when the total number of the antennae which are to carry out data transmission rate detection is relatively large, a higher preset time threshold can be set, so that more antennae will have the opportunity to carry out data transmission rate detection; when the total number of the antennae which are to carry out data transmission rate detection is relatively small, a lower preset time threshold can be set; when said time interval is relatively large, a higher preset time threshold can be set, so that more antennae will have the opportunity to carry out data transmission rate detection; when said time interval is relatively small, a lower preset time threshold can be set.
• the example selects the preset time threshold to be 500ms according to the practical experiences, and the descriptions in the following text are made on the basis of this example.
• the minimum packet loss rate at 120 Mb/s is 25% when antenna No. 10 is used. Namely, the minimum packet loss rate obtained by the AP device at the specified second data transmission rate is 25%.
• antennae having a packet loss rate which differs by not more than 12% from the minimum packet loss rate of 25% include: antenna No.10 (with a packet loss rate of 25%), antenna No.18 (with a packet loss rate of 27%), antenna No. 21 (with a packet loss rate of 28%) and antenna No. 35 (with a packet loss rate of 30%).
• the time at which antenna No.10 carries out the previous data transmission rate detection for the specified first data transmission rate 180 Mb/s is 3800 ms
• the time at which antenna No.18 carries out the previous data transmission rate detection for the specified first data transmission rate 180 Mb/s is 3700 ms
• the time at which antenna No.21 carries out the previous data transmission rate detection for the specified first data transmission rate 180 Mb/s is 3000
• the time at which antenna No.35 carries out the previous data transmission rate detection for the specified first data transmission rate 180 Mb/s is 3600 ms
• the antennae for which the time interval from the time of which to the current time exceeds the preset time threshold of 500 ms are antenna No.21 and antenna No. 35.
• the AP device needs to select an antenna from antenna
• antenna No.21 and antenna No.35 which has the minimum packet loss rate at the current data transmission rate 120 Mb/s as the antenna which is to carry out data transmission rate detection, namely, the AP device finally selects antenna No.21 as the antenna which is to carry out data transmission rate detection, namely, the antenna No. 21 will be used subsequently to carry out the data transmission rate detection for the specified first data transmission rate 180 Mb/s.
• said method comprises carrying out data transmission rate detection by the AP device via the antenna selected at block 402. That is, the AP device carries out the data transmission rate detection by sending messages at the specified first data transmission rate via the antenna selected at block 402.
• the time shown in Fig. 3 needs to be updated, namely, the time for the selected antenna is modified to be the current time, e.g. the time for the selected antenna No. 21 is modified from 3000 ms to 4150 ms.
• the time for the selected antenna is modified to be the current time, e.g. the time for the selected antenna No. 21 is modified from 3000 ms to 4150 ms.
• the antenna No. 10 with the minimum packet loss rate is used first to carry out data transmission rate detection for data transmission rate 180 Mb/s, and the time of carrying out data transmission rate detection by antenna No. 10 is recorded in Fig. 3.
• antenna No.18 is continuously used to carry out data transmission rate detection for data transmission rate 180 Mb/s, and the time of carrying out data transmission rate detection by antenna No. 18 is recorded in Fig. 3.
• This process is performed repeatedly until an antenna for which said time interval exceeds the preset time threshold of 500 ms is found and then this antenna is selected as an antenna which is to carry out data transmission rate detection for data transmission rate 180 Mb/s. Then, block 403 is performed.
• the disclosure carries out data transmission rate detection by selecting the antenna which is to carry out data transmission rate according to said time interval and the packet loss rates.
• the system can use the selected antenna to detect the high data transmission rate more accurately, thus the system performance can be improved, the optimal antenna can have an increased convergence speed and it is adapted to environment changes more quickly.
• different antennae are used to detect the high data transmission rate, so that the high data transmission rate detection is more likely to succeed and the system can reach a higher performance; more information about each of the antennae are accumulated for the high data transmission rate, and the successfully detected high data transmission rate can quickly narrow the range of detection of the optimal antenna, thus the speed of converging to obtain the optimal antenna is faster; different antennae can be detected quickly in case of environment changes, so it is better adapted to the environment changes.
• the present disclosure provides a data transmission rate detection device 500 (i.e. AP device) for use with smart antennae, which is applied to a wireless local area network, as shown in Fig. 5, said device comprises: a determination module 501 to determine that data transmission rate detection needs to be carried out for the specified first data transmission rate; a selection module 502 to select an antenna which is to carry out data transmission rate detection on the basis of a packet loss rate of each antenna at the specified second data transmission rate and the time interval between the time of carrying out the previous data transmission rate detection for the specified first data transmission rate by each antenna and the current time, wherein said specified first data transmission rate is greater than said specified second data transmission rate; and a detection module 503 to carry out the data transmission rate detection via said selected antenna.
• a determination module 501 to determine that data transmission rate detection needs to be carried out for the specified first data transmission rate
• a selection module 502 to select an antenna which is to carry out data transmission rate detection on the basis of a packet loss rate of each antenna at the specified second data transmission rate and the time interval
• the selection module 502 is particularly to acquire the minimum packet loss rate at the specified second data transmission rate, and select, among the antennae for which said time interval is greater than a preset time threshold and the difference between the packet loss rate at said specified second data transmission rate and said minimum packet loss rate does not exceed a preset packet loss rate threshold, an antenna having the minimum packet loss rate at the specified second data transmission rate as the antenna which is to carry out data transmission rate detection.
• Said preset packet loss rate threshold is to set according to a random packet loss rate produced when sending packets by an air interface.
• Said preset time threshold is to set according to the total number of the antennae which is to carry out data transmission rate detection and/or said time interval.
• the packet loss rate information obtained by combination of each data transmission rate and each antenna is recorded, and the time of carrying out the previous data transmission rate detection by each antenna is recorded, wherein said specified first data transmission rate value and said specified second data transmission rate value are recorded in the database and are two adjacent data transmission rate values.
• the above examples can be implemented by hardware, software or firmware or a combination thereof.
• the various methods, processes and functional modules described herein may be implemented by a processor (the term processor is to be interpreted broadly to include a CPU, processing unit, ASIC, logic unit, or programmable gate array etc.).
• the processes, methods and functional modules may all be performed by a single processor or split between several processers; reference in this disclosure or the claims to a 'processor' should thus be interpreted to mean One or more processors' .
• the processes, methods and functional modules be implemented as machine readable instructions executable by one or more processors, hardware logic circuitry of the one or more processors or a combination thereof. Further the teachings herein may be implemented in the form of a software product.
• the computer software product is stored in a storage medium and comprises a plurality of instructions for making a computer device (which can be a personal computer, a server or a network device such as a router, switch, access point etc.) implement the method recited in the examples of the present disclosure.
• a computer device which can be a personal computer, a server or a network device such as a router, switch, access point etc.
• the modules in the device in the examples can be distributed in the device in the examples according to the descriptions of the example, or they can be changed so as to be in one or more devices that are different from that in the examples.
• the modules in the above examples can be either combined into one module or further divided into several sub-modules.

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• 2011
  • 2011-08-24 CN CN201110243925.5A patent/CN102427392B/zh active Active
• 2012
  • 2012-08-23 WO PCT/CN2012/080485 patent/WO2013026398A1/en active Application Filing

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