TWI542237B - Apparatus and method for adjusting transmission power of communication system - Google Patents

Description

Transmission power adjustment method and device thereof applied in communication system

The present invention relates to a communication system, and more particularly to a transmission power adjustment method in a communication system.

Wireless communication refers to the technique by which at least two endpoints can be transmitted without the use of a wire. In the field of communications, wireless communication is basically regarded as a branch of telecommunication. Extendably, wireless communications include point-to-point communications, point-to-multipoint communications, cell phones or other wireless networking applications.

In wireless applications, it is important to effectively adjust the transmission power. When the distance between the two endpoints is relatively close, reducing the transmission power can further reduce the power consumption, and can also reduce the interference of other wireless devices, and enhance the compatibility of the wireless device.

The existing transmission power adjustment technology adjusts the transmission power according to the Received Signal Strength Indication (RSSI) indicator. However, when the two end points have a mechanism for automatically adjusting the transmission power, since the two end terminals are both estimating the distance and adjusting the transmission power, the endpoints of both ends are estimated to be inaccurate and misjudged.

Therefore, there is a need to propose a method for adjusting the transmission power of a wireless network to improve the disadvantages of the prior art.

One of the objects of the present invention is to provide a transmission power adjustment method for a wireless network to improve the disadvantages of the prior art.

200‧‧‧ In the initial stage, the endpoint A continuously transmits a detection packet to the endpoint B according to a plurality of different transmission power levels.

210‧‧‧ Generate a response packet from Endpoint B

220‧‧‧ Statistics of these response packets for a statistical value

230‧‧‧ Analyze the statistics to determine at which transmission power level to transmit at least one data packet to the endpoint B

300‧‧‧In the current unit time, the endpoint A continues to transmit according to a number of different transmission power levels Send a detection packet to the endpoint B

310‧‧‧This endpoint B generates a response packet that should be returned to endpoint A

320‧‧‧ After the end of the current unit time, the response packets are counted to obtain a statistical value

330‧‧‧Analyze the statistical value to determine a plurality of different transmission power levels that the endpoint A transmits to the endpoint B in a next unit time

400‧‧‧ In a current unit time, the endpoint A performs a data packet transmission to the endpoint B according to a transmission information table containing one of a plurality of sets of transmission information.

410‧‧‧This endpoint B generates an ACK packet that should be returned to endpoint A

420‧‧‧ After the current unit time, the ACK packets are counted to obtain a statistical value

430‧‧‧After the current unit time, analyze the statistics to update the transmission information form

Figure 1a is a schematic diagram of the adjustment of transmission power in the first embodiment of the present invention.

Figure 1b is a flow chart of adjusting the transmission power of the first embodiment of the present invention.

Figure 2a is a schematic diagram of the adjustment of transmission power in the second embodiment of the present invention.

Figure 2b is a flow chart of adjusting the transmission power of the third embodiment of the present invention.

Figure 3a is a schematic diagram of adjusting the transmission power of the fourth embodiment of the present invention.

Figure 3b: Displaying a transmission information table containing a plurality of sets of transmission information indexes, wherein each group of transmission information indexes includes a transmission power level and a transmission rate.

Figure 3c is a flow chart of adjusting transmission power in the fourth embodiment of the present invention.

In the first embodiment, please refer to FIG. 1a and FIG. 1b together. Figure 1a shows the initial phase of a unit of time (also known as the train process), a mechanism in which an endpoint A is separated from the endpoint B by a wireless network protocol (for example, 802.11) RTS/CTS. A schematic diagram of adjusting the transmission power. FIG. 1b is a flow chart of a method for adjusting transmission power according to the first preferred embodiment of the present invention. The mechanism of the RTS/CTS is that the endpoint A sends an RTS (Request to Send) request packet before transmitting the data. When the endpoint B receives the RTS packet, the endpoint B sends the CTS (Clear). To Send), telling the endpoint A to send the data and telling other wireless devices that no data can be transmitted during this time to avoid collision.

Before the description, it is assumed that a plurality of different transmission powers transmitted by the endpoint A to the endpoint B are divided into three levels (low transmission power level L1, medium transmission power level L2, high transmission power level L3). Of course, it can be divided into other levels, not limited to three levels.

In the first embodiment, initially, in the case where the endpoint A is not yet familiar with the transmission power level required by the endpoint B, in step 200, the transmission process is divided into a plurality of unit time (1s), In the initial phase (10ms) of each unit time, the endpoint A successively transmits the RTS packet as a detection packet to the endpoint B at a plurality of different transmission power levels until the endpoint B is generated for use. The CTS packet of endpoint A should be encapsulated, that is, the endpoint A will contain control information of a destination address (destination address) through the protocol according to a low transmission power level L1. One of the RTS packets is delivered to the endpoint B. At this time, in step 210, the endpoint B receives the power M1 from the RTS packet of the low transmission power level L1 from the endpoint A (which has passed the channel attenuation) and presets in the endpoint B. The predetermined received power threshold M is determined to determine whether a CTS packet from the endpoint A is generated from the endpoint B. If Endpoint B believes that it has not received the RTS packet of the low transmission power level L1, then of course, it will not generate a CTS packet back to the endpoint A.

When the endpoint B determines that the received detected packet power M1 does not exceed the predetermined received power threshold M, it does not generate a CTS packet that should detect the packet A. After a predetermined period of time, the endpoint A does not receive the CTS packet, and returns to step 200, the endpoint A is based on a medium transmission power level L2 that is one level greater than the low transmission power level L1, through the communication protocol. The RTS packet is delivered to the endpoint B. At this time, in step 210, the endpoint B receives the power M2 from the RTS packet (which has passed the channel attenuation) of the transmission power level L2 from the endpoint A, and the preset in the endpoint B. Determining a received power threshold M to determine whether to generate a response from the endpoint B One of the endpoint A CTS packets.

When the endpoint B does not generate the CTS packet corresponding to the endpoint A because the received power M2 corresponding to the RTS packet of the medium transmission power level L2 does not exceed the predetermined received power threshold M, wait for one After the predetermined unit time and the endpoint A does not receive the CTS packet, the process returns to step 200, and the endpoint A transmits the communication protocol according to a high transmission power level L3 that is one level larger than the medium transmission power level L2. An RTS packet is transmitted to the endpoint B. At this time, in step 210, the endpoint B receives the power M3 and the preset in the endpoint B for the RTS packet (which has passed the channel attenuation) of the high transmission power level L3 from the endpoint A. The predetermined received power threshold M is determined to determine whether a CTS packet corresponding to one of the RTS packets is generated from the endpoint B. .

When the endpoint B generates a CTS packet corresponding to one of the RTS packets because the power M3 of the received RTS packet is greater than or equal to the predetermined received power threshold M. The CTS packet is transmitted from the endpoint B to the endpoint A via the communication protocol. It should be understood that the present invention utilizes the communication of the RTS/CTS packet by IEEE 802.11 to protect the secure transmission of a data packet, and the endpoint A transmits a null data packet to the endpoint B through the protocol. And the endpoint B receives an acknowledgment packet (acknowledge packet) to the endpoint A after receiving the null data packet. After the endpoint A receives the CTS packet and transmits the zero data packet, the endpoint A retransmits a detection packet to the endpoint B according to the multiple different transmission powers, that is, the endpoint. A again according to a low transmission power level L1, and transmits the RTS packet to the endpoint B through the communication protocol until the initial phase ends.

In one embodiment, the received power threshold M in the endpoint B remains constant. In another embodiment, the endpoint B is based on the received power threshold M in the endpoint B. Dynamically changing the value of the received power threshold M along with the different transmission power levels of the endpoint A and the distance between the endpoint B and the endpoint A, based on the foregoing conditions, to determine Whether a CTS packet from one of endpoints A should be generated from the endpoint B.

If the endpoint B receives the RTS packet with the medium transmission power level L2 from the endpoint A, it is determined that the received power M2 after channel attenuation is a receivable power level (in other words, M2>=M ), the endpoint B generates a CTS packet that is returned to the RTS packet of the transmission power level L2. Thereafter, the CTS packet is transmitted from the endpoint B to the endpoint A through the communication protocol. After receiving the CTS packet, the endpoint A transmits a null data packet to the endpoint B through the communication protocol.

In an initial phase of a unit time, after the endpoint A receives the CTS packet transmitted from the endpoint B, step 200 is continuously performed (the endpoint A continuously transmits according to a plurality of different transmission powers) As an RTS packet of the detection packet to the endpoint B), after performing step 200 to step 210, the endpoint B re-determines according to the received power threshold value M predetermined by the endpoint B to determine whether from the terminal Point B generates a CTS packet that should be returned to endpoint A.

After the initial phase (10ms), step 220 is performed to count the CTS packets to obtain a statistical value, as shown in Table 1.

Step 230 is performed to analyze the statistic to determine that the endpoint A is in the initial stage. Thereafter, at least one data packet is transmitted to the end point B according to which transmission power until the end of the unit time. There are many ways to analyze this statistic. For example, if the number of transmission power levels is compared, according to Table 1, L2 is a suitable transmission power; for example, the ratio of the number of CTS packets corresponding to the transmittable power level to the percentage of the total number of CTS packets received is More than one threshold (in 75%), the ratio of L1 is 3/20, the ratio of L2 is (3+11)/20, and the ratio of L3 is (3+12+6)/20, due to L2 The ratio of 70% is not greater than the threshold value, so L3 is a more suitable transmission power. During the remaining time of the unit time, the endpoint A transmits the data packet to the endpoint B by analyzing the appropriate transmission power obtained by the statistical value.

In the second embodiment, please refer to Figures 2a and 2b. The 2a is a schematic diagram of adjusting the transmission power in a mechanism of one end A and one end of the distance B through a wireless network protocol (for example, 802.11) RTS/CTS in a unit time. Figure 2b is a flow chart of a method for adjusting transmission power according to a second preferred embodiment of the present invention.

Initially, in the case that the endpoint A is not yet familiar with the transmission power level required by the endpoint B, in step 300, in the current unit time (for example, 1 s), the endpoint A is based on a plurality of different transmissions. The power is continuously transmitted as one of the detection packets to the endpoint B. For example, the endpoint A first transmits the RTS packet to the endpoint B at a low transmission power level L1. At this time, in step 310, the endpoint B receives the channel-attenuated received power M1 for the RTS packet of the low transmission power level L1 from the endpoint A (ie, M1=L1-P, where P is channel-attenuated The power is determined by predetermining a predetermined received power M in the endpoint B to determine whether a CTS packet of the RTS packet is generated from the endpoint B.

Knowingly, the endpoint B does not generate the CTS packet corresponding to the endpoint A because the received power M1 does not exceed the predetermined received power M. After a predetermined unit time, If the endpoint A does not receive the CTS packet, it returns to step 300, and the endpoint A transmits an RTS packet to the end through the communication protocol with a medium transmission power level L2 that is one level higher than the low transmission power level L1. Point B.

At this time, in step 310, the endpoint B receives the power M2 and presets in the endpoint B for one of the RTS packets (which have been channel attenuated) from the transmission power level L2 in the endpoint A. The predetermined received power M is determined to determine whether a CTS packet corresponding to one of the RTS packets is generated from the endpoint B.

For IEEE 802.11 to utilize the communication of the RTS/CTS packet to protect the secure transmission of a data packet, the endpoint A may transmit a data packet to the endpoint B through the communication protocol after receiving the CTS packet. The data is transmitted, and then the RTS packet as the detection packet is continuously transmitted to the endpoint B in a plurality of different transmission powers. In the third embodiment, the first embodiment and the second embodiment can be combined. That is, in the second embodiment, the CTS packet results at the unit time (1 s) are counted to determine the transmission power of the next unit time.

For example, after the current unit time (1 s), the CTS packets are counted to obtain a statistical value, as shown in Table 2.

Step 330 is executed to determine whether the statistic is greater than a threshold to determine a plurality of different transmission power levels that the endpoint A transmits to the endpoint B within a next unit time (1 s).

For example: for the endpoint A after the current unit time according to the table 2 The number of CTS packet statistics is analyzed, that is, the transmission power level corresponding to the CTS packet of the low number of times is no longer the transmission power level required to train the endpoint A to transmit the RTS packet in the next unit time. In other words, the transmission power that is less likely to be used is temporarily not used. Taking Table 2 as an example, since the number of CTS packets of L1 is too low (far less than other times), L1 is not used in the next unit time.

Please refer to FIG. 3a, which is a schematic diagram of a method for adjusting transmission power according to a fourth preferred embodiment of the present invention. As shown in FIG. 3a, the endpoint A transmits a data packet to the endpoint B according to one of the transmission information tables including the plurality of transmission information (as shown in FIG. 3b), and the endpoint B can successfully receive the packet according to whether it can successfully receive the packet. The data packet determines whether a response packet (which is represented by an acknowledgement packet) is generated from the endpoint B, and the transmission information table is updated according to the status of the response packet as the endpoint. A. The data packet is transmitted to the endpoint B for selection of a preferred transmission power level and a transmission rate basis.

In a WLAN environment, the endpoint A and the endpoint B communicate via a communication protocol compliant with the IEEE 802.11 wireless network standard of the Institute of Electrical and Electronics Engineers (IEEE). The transmission rate levels in the table conform to the IEEE 802.11 standard, the IEEE 802.11a standard, the IEEE 802.11b standard, the IEEE 802.11g standard, the IEEE 802.11i standard, or the IEEE 802.11n standard, and the transmission information index in the table Adjust according to "auto-rate fall back".

Please refer to FIG. 3b and FIG. 3c together (the figure is a flowchart of a method for adjusting transmission power in the fourth preferred embodiment of the present invention). In step 400, the terminal A is in a current unit time (2 μs). Data packet transmission is performed on the endpoint B according to one of the transmission information tables of FIG. 3b, wherein each group of transmission information indexes includes a transmission power and a transmission rate.

As shown in Figure 3a, the endpoint A is first indexed within a TRY #1 index. A high speed transmission rate and a low transmission power are transmitted to the end point B via the communication protocol.

In step 410, the endpoint B determines whether the data packet can be successfully received under the condition of TRY #1, to determine whether a response packet is sent back to the data packet (in other words, whether the endpoint A receives the endpoint from the endpoint) B's response packet). If after a predetermined time and the endpoint A does not receive a reply packet from one of the data packets, the endpoint A transmits at a high speed transmission rate and one medium according to the conditions in one of the TRY #2 indexes of the table. Power, through which a data packet is transmitted to the endpoint B. At this point, if the data packet transmitted by the transmission information in the TRY #2 index is an acceptable data packet for the endpoint B, the endpoint B transmits an acknowledgement packet ACK to the endpoint A through the communication protocol. . The endpoint A then returns to step 400.

It should be explained that, since the specific transmission information threshold preset in the endpoint B can be fixed or dynamically changed according to the distance between the endpoint B and the endpoint A, Therefore, when the endpoint A receives an acknowledgment packet ACK transmitted from the endpoint B, the endpoint A re-executes step 400 to step 410 until the end of the current unit time.

In step 420, after the current unit time, the acknowledgement packets ACK are counted to obtain a statistical value.

In step 430, after the current unit time ends, the statistical value is analyzed to update a transmission information table for the next unit time. For example: Temporarily remove some TRYs. For example, it is determined whether the statistical value of each TRY#N is greater than a threshold value to determine another transmission information table used in the next unit time. For example, if the number of acknowledgment packets in the TRY #1 index to TRY #7 index is less than one threshold, another transmission information table used in the next unit time will not appear that the number of acknowledgment packets is less than the threshold. The transmission information corresponding to the index. this In addition, the transmission power and the statistical value of the transmission rate may be distinguished. For example, if the total number of low transmission powers is too small, the low transmission power TRY#1 in the transmission information table is not used in the next unit time; for another example: If the total number of high-speed transmission rates is too small, the high-speed transmission rate TRY#1~TRY#4 is not used in the transmission information table of the next unit time.

In this embodiment, the information training of the endpoint A is performed in the current unit time. However, the transmission of information training can also be carried out in the initial phase of a unit of time. Moreover, under the WLAN, a preferred transmission rate required for the terminal A to transmit a data packet to the endpoint B through the communication protocol can also be from step 200 to step 230 and FIG. 2b of FIG. 1b. Step 300 to step 330 are obtained.

While the present invention has been described in its preferred embodiments, the present invention is not intended to limit the present invention, and it is obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application attached.

200‧‧‧ In the initial phase of unit time, the endpoint A continuously transmits a detection packet to the endpoint B according to a plurality of different transmission power levels.

210‧‧‧ Determine the detection packet at a particular transmission power level to determine whether to generate a response packet from endpoint B

220‧‧‧ Statistics of these response packets for a statistical value

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Claims (10)

An adjustment method applied to a communication system, the communication system having a first endpoint and a second endpoint, the method comprising the steps of: in an initial phase of a unit time, the first endpoint is based on a plurality of different transmission powers, sequentially transmitting a plurality of detection packets to the second endpoint, the plurality of detection packets being required to transmit a packet; receiving and counting at least one response packet from the second endpoint, the response The packet is an approved transmission packet, where the response packet corresponds to one of the plurality of detection packets; at the end of the initial phase, based on the statistics of the response packets to generate a statistical value; and analyzing the statistical value, Determining, in the unit time, transmitting a data packet to the second endpoint in one of the plurality of transmission powers. The method of claim 1, further comprising the first endpoint transmitting a zero data packet after receiving the response packet. The method of claim 2, further comprising: after receiving the acknowledgement packet of the zero-data packet, the first endpoint retransmits the plurality of detection packets according to the plurality of different transmission power levels. To the second endpoint. The method of claim 1, wherein the detection packet contains at least address information of the second endpoint. The method of claim 1, wherein in the initial stage, the first endpoint sequentially transmits the plurality of detection packets to the second endpoint from a minimum to a maximum transmission power. For example, the method described in claim 1 further includes reopening after the end of the unit time. The initial phase of the second unit time is used to determine the data packet transmission power in the second unit time. An adjustment method applied to a communication system, the communication system includes a first endpoint and a second endpoint, the method comprising the steps of: according to a plurality of different transmission powers in a unit time Continuously transmitting a plurality of detection packets to the second endpoint, the plurality of detection packets being a request packet (RTS packet); receiving at least one response packet from the second endpoint, the response packet being an approved transmission packet (CTS packet), wherein the response packet corresponds to one of the plurality of detection packets; according to the response packet to obtain a statistical value; and analyzing the statistical value to determine the first endpoint in the next unit time Transmitting the transmission power of the packet to the second endpoint. The method of claim 7, wherein the step of the first endpoint continuously transmitting the plurality of detection packets to the second endpoint according to the plurality of different transmission powers is from a minimum to a maximum transmission power. The level is transmitted. The method of claim 7, wherein the second endpoint transmits a data packet upon receiving the response packet. The method of claim 9, further comprising: after receiving the confirmation packet of the data packet, the first endpoint retransmits the plurality of detection packets to the first according to the plurality of different transmission powers. Two endpoints.