CN101156458A - Wireless communication method and device for dynamically adapting packet transmission rate - Google Patents

Abstract

A method and apparatus for use by a first transceiver, (e.g., wireless transmit/receive unit (WTRU), access point (AP), node) for adjusting the transmission rate of packets transmitted to a second transceiver based on signals the first transceiver receives from the second transceiver. In one embodiment, a transmission packet error rate (Tx PER) process is used to adjust the packet transmission rate. In another embodiment, a relative signal strength indicator (RSSI)-based process is used to determine the RSSI of packets received at the first transceiver from the second transceiver for adjusting the packet transmission rate. In another embodiment, transmission quality indicators are measured at the second transceiver and are sent to the first transceiver, which derives a new packet transmission rate therefrom. The Tx PER and RSSI-based processes may be used individually, in combination, or in conjunction with other processes.

Description

Wireless communication method and device for dynamically adapting packet transmission rate

technical field

The present invention relates to data transmission in wireless communication systems. More particularly, the invention relates to dynamically adapting packet transmission rates in response to changing fading conditions.

Background technique

Wireless communication systems, such as wireless local area networks (WLANs), are well known in the art. Typically, the system includes transceivers (ie, communication stations (STAs)) that transmit and receive wireless communication signals with each other. Depending on the type of system, the transceivers may take the form of access points (APs), wireless transmit/receive units (WTRUs), nodes or the like.

FIG. 1 shows a conventional wireless communication system 10 in which an AP 12 can provide communication services to a plurality of WTRUs 14 . Access point 12 may communicate with network 18 via optional access controller (AC) 16, thereby providing additional network services to WTRU 14, such as access to the Internet or the Public Service Telephone Network (PSTN). Alternatively, access point 12 may communicate directly with network 18 without going through optional access controller 16 .

In theory, all connections within the system 10 can operate at the highest achievable transfer rate to maximize performance and overall system capacity. However, receivable quality cannot always be achieved at higher data rates due to the relatively high signal-to-noise ratios (SNRs) at the receiver.

Depending on the signal-to-noise ratio perceived by the transceiver receiving the packet, this creates favorable conditions for adjusting the rate at which the packet is transmitted. However, system 10 does not provide a mechanism for transferring perceived channel quality in terms of received signal power, signal-to-noise ratio, or packet error rate (PER) to the packet source. Therefore, the decision basis for adjusting the transmission rates of APs 12 and WTRUs 14 in system 10 is limited to local transmission conditions.

Contents of the invention

The present invention is concerned with a first transceiver (e.g. WTRU, access point, node or the like) receiving a signal from a second transceiver which is used by the first transceiver to adjust the signal transmitted to the Method and device for packet transmission rate of the second transceiver. In one embodiment, transmission packet error rate (TxPER) processing is used to adjust the packet transmission rate. In another embodiment, relative signal strength indicator (RSSI) based processing is used whereby the RSSI of packets received by the first transceiver from the second transceiver is used to adjust the packet transmission rate . In another embodiment, a transmission quality indicator is measured at the second transceiver and sent to the first transceiver, which can drive a new packet transmission rate based on the quality indicator. Optionally, the second transceiver can determine a preferred packet transmission rate and communicate it to the first transceiver, which can then adjust its packet transmission rate.

Although two different packet rate-determining processes (ie, TPER processing and RSSI based processing) are disclosed herein, these processes may be used individually, in conjunction with each other, or in conjunction with other processes.

According to the invention, a transceiver may select a preferred data transmission rate from among several available rates based on measurements at the transceiver. These measurements are the received signal strength (Rx power) of packets received at the transceiver, and the transmission packet error rate of signals transmitted by the transceiver, which can be calculated by assuming that a packet is transmitted every time its corresponding acknowledgment (ACK) is not Inferred by error when received from another transceiver. The transceiver quickly establishes the best available data rate while maintaining acceptable quality of service (QoS). Thereafter, the transceiver can adapt its transmission rate in response to changing fading conditions.

Description of drawings

The present invention can obtain more detailed understanding from following description of preferred embodiment and accompanying drawing, wherein:

Figure 1 shows a conventional wireless communication system;

FIG. 2 is a block diagram of a wireless transmission/reception unit configured according to the present invention;

Fig. 3 is a flow chart of all rate adaptation processes implemented according to the present invention;

Fig. 4 is the basic processing flowchart of the transmission packet error rate of all rate adaptation processing of Fig. 3;

Fig. 5 is the flow chart of relative signal strength pointer training processing of all rate adaptation processing of Fig. 3;

6 is a flowchart of another embodiment of the relative signal strength pointer training process of the overall rate adaptation process of FIG. 3; and

7 is an example of an alternative relative signal strength pointer training process to the overall rate adaptation process of FIG. 3 .

Abbreviation list

ACK confirm AP access point BS base station

CS Client Station CTS   Clean up and send MAC   Media Access Control NF Noise Index PER   Packet Error Rate Pwr power QoS service quality RSSI Relative signal strength pointer RTS Request to send Rx take over SNR Signal to Noise Ratio STA stand STAT Tx   Teleportation station STA Rx   Receiving station Tx send TxPwr   Transmission power WLAN  Wireless Local Area Network

Table 1

Detailed ways

Hereafter, the access point nouns used include but are not limited to base stations, B nodes, address controllers, wireless routers or wireless environments that provide wireless transmission/reception units for wireless access to the network connected to the access point Any other interfacing device in .

Hereinafter, the term WTRU as used includes, but is not limited to, client station, user equipment, station, mobile station, fixed or mobile subscriber unit, pager, or any other type of user operable in a wireless environment device. The wireless transmit/receive unit includes personal communication devices such as telephones, video phones and Internet backup phones with network connections. In addition, the WTRU includes portable personal computing devices, such as personal digital assistants (PDAs) and notebook computers with wireless modems like network functions. WTRUs that are portable or repositionable are called mobile units.

Hereinafter, the wireless connection used is defined as the wireless communication between a pair of nodes that can transmit and receive packets with each other. Each wireless link consists of a pair of nodes between which the roles of transmitter and receiver of packets are switched back and forth in time. For example, a wireless communication system operating in an architecture mode in which two WTRUs communicate with a single AP includes two wireless connections. A rate control process should reside in each transmitting node and its purpose is to determine the optimal rate at which each packet is transmitted for each active wireless connection.

Preferably, implementing the various transmitter and receiver functions described herein may be incorporated on a single integrated circuit, such as an application-specific integrated circuit. However, the circuit could just as easily be implemented using multiple discrete components and/or discrete integrated circuits.

The specific transmitter and receiver configurations described herein are provided by way of illustration only and not limitation. Those of ordinary skill in the art will recognize other variations and modifications consistent with the present invention.

The present invention is to enable a transceiver (ie WTRU, AP, node) to dynamically adapt its transmission rate according to the time-varying propagation of each wireless channel being engaged with one or more wireless connections. To this end, the present invention relies on two processes to determine the optimal transmission rate depending on the specific measurement availability and validity. In the first process, TPER, referred to herein as the TPER-based process, is used to determine the optimal transmission rate. Alternatively, the optimal transmission rate is determined based on a relative signal strength index or other received packet metric related to its transmission power, which correlates to a transmission packet error rate of transmitted packets. The RSSI is correlated with the transmission packet error rate in a process referred to herein as the RSSI training process. Although RSSI is used in the description of the preferred embodiment of the RSSI training process, alternative embodiments may use other metrics such as signal-to-noise ratio.

FIG. 2 is a block diagram of a WTRU 100 configured in accordance with the present invention. The same configuration example disclosed herein for WTRU 100 may also be incorporated into an access point. The WTRU 100 includes at least one antenna 102 , a transmitter 104 , a receiver 106 , a processor 108 , a transmission rate database 110 and a memory 112 . The transmitter is configured to transmit the output signal 114 via the antenna 102 at a transmission rate selected from a plurality of available transmission rates stored in the transmission rate database 110 . The receiver 106 is configured to receive an input signal 116 from the antenna 102 . Processor 108 is coupled to transmitter 104 , receiver 106 , transmission rate database 110 and memory 112 . The processor 108 selects a transmission rate from the transmission rate database 110, and changes the current transmission rate of the transmitter 104 to the selected rate. This selection may be based on output signal 114 evaluation, output signal 114 and input signal 116 evaluation, or it may be based on a rate command received at receiver 106 . Memory 112 is used to store data for input signal 116 and/or output signal 114 , and/or for rate commands received at receiver 106 . The processor 108 is configured to process data stored in the memory 112 and store the processed data results in the memory 112 for further access to select and change the transmission rate of the transmitter 104 .

The WTRU 100 further includes a plurality of packet transmission counters, including a total successful packet transmission counter 120, an individual packet transmission error counter 122, a total failed packet transmission counter 124, a relative signal strength indicator level total packet transmission counter 126 , and a relative signal strength indicator level packet transmission error counter 128 . The functionality of packet transmission counters 120, 122, 124, 126, and 128 may be implemented on an individual basis or as a maintained group by one or more databases, processors, software, or the like. For example, sets of packet transmission counters 120, 122, 124, 126, and 128 and associated measurements may be maintained to individually control each station, access point, wireless T/R unit 100 communicating on a particular communication link, The packet transfer rate associated with the receiving unit or similar.

Before describing the processes performed by the present invention, it is advantageous to define a number of terms listed in Table 2 below. While the process of the present invention will be described in these terms, it should be understood that these terms need not be used; rather, the terms are merely a convenience for describing the nature of the process. In one implementation, parameters may be stored in memory and updated as needed, or may be maintained and updated in any suitable manner.

parameters illustrate example Maximum duration The maximum duration for which a measurement or command from a transmitter to a node to which a packet is transmitted is valid. The max duration parameter should preferably represent the consistency time of the channel. The received packet can be of any type (such as DATA, ACK, RTS, CTS or similar) 100ms allowable rate A list of supported rates sorted by transporters in ascending order. The allowable speed can be represented by a vector stored in memory, where each position of the vector corresponds to a specific speed. [6, 9, 12, 18, 24, 36, 48, 54] Mbps of IEEE 802.11a Preset rate The rate that should be used by the transmitter when rate control is activated. This can be represented by the allowable rate vector start pointer. 8 (marked default rate is the 8th highest supported rate, such as 54Mbps in 802.11a system) current speed The rate used by the transmitter to transmit the next packet. This may be represented by the allowable rate vector current pointer. 5 (indicating that the next packet will be transmitted at the 5th highest supported rate, such as 24Mbps in the 802.11a system) Maximum speed pointer The number of different transfer rates supported 8

rate down trigger A predetermined pattern or plan for adjusting the transmission rate in response to successive transmission errors, which indicates whether the transmission rate should be reduced, and if so, by how much, for retransmission attempts. The pattern should be stored as a vector. For example, in an IEEE 802.11a system, [0, 0, 1, 1, 2, 2, 1, 0] means that the WTRU operates at 54 Mbps until the third bit when the transmission rate is reduced by one level to 48 Mbps. Retransmission (that is, after three errors) does not reduce its transmission rate. If an error occurs, the rate is reduced by one level on the fourth retransmission to 36Mbps, and thereafter by two levels on the fifth (to 18Mbps) and sixth retransmission (to 9Mbps), and then by one level (up to 6Mbps, the lowest supported rate). [0, 0, 1, 1, 2, 2, 1, 0] rate increase ratio The maximum allowed ratio of failure to successful packet transmission 0.10 Packets required for rate increase The maximum number of packets that must be sent since the last rate change to allow the transfer rate to increase 10 Good Packet Count The number of successful packets delivered to a specific WTRU. This count is re-initialized to zero after the rate change is implemented. bad packet count The number of failed packets delivered to a specific WTRU. This count is re-initialized to zero after the rate change is implemented. retry count The number of failed delivery attempts for a given packet. This count is re-initialized to zero when the packet is successfully transmitted.

Table 2

FIG. 3 is a flowchart of an overall rate adaptation process 300 implemented in accordance with the present invention. The transmission rate is determined using the transmission packet error rate-based processing or relative signal strength index-based processing implemented by the processor 108 in the WTRU 100 of FIG. 2 . The decision of which process to use is based on whether the RSSI-based process has been previously trained, and whether a valid RSSI measurement is available at a particular RSSI level. If so, RSSI based processing is used to determine the transmission rate. Otherwise, the transmit packet error rate based processing is used. In either case, packets are then transmitted at a rate determined by the process, and subsequent success or failure of packet transmission is used to dynamically train the relative signal strength pointer based process and adjust the transmission rate.

Effective RSSI measurements are defined as relative SSI measurements of packets received from the node to which the transmitter last transmitted the packet within a predetermined duration (here designated as the maximum duration). The maximum duration represents the channel consistency time. The received packet can be of any type, such as DATA, ACK, RTS, CTS or similar.

As shown in FIG. 3, when the first station (that is, the wireless transmission/reception unit 100) prepares to transmit the packet to the second station for the first time by setting the packet transmission rate of the first station to the preset rate, all rate adaptation processing 300 activation (step 305). When the first station has a packet to transmit to the second station (step 310), it is determined whether there were any valid RSSI measurements available for any packet received from the second station during the last maximum duration (step 315).

If no packets have been received or the measurement is available for any received packets for the duration, a transmit packet error rate based process is implemented to determine the packet transmit rate of the first station (step 320), which is later will be detailed.

However, if valid RSSI measurements are determined to be available in step 315, then a determination of the relative signal strength indicator level available for valid RSSI measurements is performed (step 325). In step 325, if valid RSSI measurements are determined to exist at more than one RSSI level, then a representative RSSI level is determined. The representative RSSI level may be based on the last RSSI value, or may be static (eg, average), based on a number of RSSI values, or a combination of other RSSI values Base. In step 330, it is determined whether the RSSI process has been trained at the RSSI level during the last maximum duration. If so, the packet transmission rate of the first station is set to the RSSI level preferred rate as determined by the RSSI training process (step 335), the packet is transmitted (step 340) and The relative signal strength indicator training process is performed (step 345). Process 300 returns to step 310 when the first station has another packet to transmit to the second station. The success or failure of a transmitted packet is used to dynamically update the preferred transmission rate indicated by the relative signal strength pointer training process 345, as will be explained below as the transmission packet error rate base process is described.

In step 330, if it is determined that the relative signal strength indicator process is not trained at this relative signal strength indicator level during the last maximum duration, then the transmit packet error rate based process is implemented to determine the packet transmission rate of the first station (step 320). The packet is then transmitted (step 340) and the RSSI training process is performed (step 345).

FIG. 4 is a flow chart of the transmission packet error rate based processing 320 of the overall rate adaptation processing 300 of FIG. 3 . Generally, according to the transmission packet error rate based process 320, the transmitter 104 in the WTRU 100 of FIG. 2 can adjust its packet transmission rate by reflecting the transmission events it experiences when transmitting to a receiving node.

If the transmitter 104 of the WTRU 100 of FIG. 2 experiences continuous packet transmission errors, its packet transmission rate is reduced according to a predetermined schedule or pattern designated herein as Rate Down Trigger. The rate down trigger may be a vector stored in the memory 112 of the WTRU 100 of FIG. 2 . After each consecutive packet transmission error, the rate down trigger may indicate whether the packet transmission rate should be reduced before the next packet retransmission attempt, and if so, by how much. If so, the instructed rate reduction is then implemented. The packet transmission rate is reduced in this manner until the packet is successfully transmitted, or until the packet transmission rate is reduced to a predetermined minimum packet transmission rate.

For example, if the WTRU 100 is configured for an IEEE 802.11a system, the supported packet transmission rates (that is, the supported packet transmission rate levels) sorted in ascending order steps are 6, 9, 12 , 18, 24, 36, 48 and 54Mbps. In this example, the rate down trigger vector of [0, 0, 1, 1, 2, 2, 1, 0] instructs WTRU 100 to wait until after the third retransmission attempt (i.e., the specific packet three transmission error After that), the packet transmission rate will be reduced. At this point, the packet transmission rate will be reduced by one step. Thus, if the WTRU 100 operates at 54 Mbps after the third transmission error, the transmission rate will be reduced by one step to 48 Mbps, and the packet will be retransmitted. If the transmission error still occurs, the fourth retransmission, the rate is then reduced by one step to 36Mbps, then the fifth (to 18Mbps) and the sixth retransmission (to 9Mbps) are further reduced by two steps, and then reduced by one step (to 6Mbps, the lowest supported rate).

On the other hand, if the transmitter 104 of the WTRU 100 experiences consistent consecutive packet transmission errors, the transmission rate of the transmitter 104 is increased according to the transmission packet error rate based process 320 . In this example, when the transmitted packet error rate experienced by the transmitter 104 drops below a certain threshold for a sufficient number of packets to be transmitted to the receiving node, the transmission rate is increased to the next support step.

As shown in Figure 4, if the acknowledgment (ACK) is received (step 405), the total successful packet transmission counter 120 in the WTRU 100 is incremented, and the individual packet transmission errors in the WTRU 100 Counter 122 is reset to zero (step 430). As explained below, these counters 120, 122 are used to determine whether the transmission rate should be increased.

If the acknowledgment is not received at step 405, the total failed packet transmission counter 124 in the WTRU 100 is incremented, and the individual packet transmission error counter 122 is also incremented (step 410). The rate down trigger vector is checked to determine whether the packet transmission rate should be decreased for individual packet transmission error counts, and if so, by how many steps (step 415). If the rate down trigger indicates that the packet transmission rate should not be reduced, then the same packet is prepared for retransmission. However, if the rate down trigger indicates at step 415 that the packet transmission rate should be reduced by one or more steps, then the packet transmission rate is reduced by the number of steps indicated by the rate down trigger, and the total successful packet transmission counter 120 and the total failure The packet transfer counter 124 is reset to zero (step 420). The same packet is then prepared for retransmission at the packet transmission rate indicated by the rate down trigger (step 425). The transmission packet error rate based process 320 may be repeated during the communication session until the packet transmission rate equals the minimum supported transmission rate or until an acknowledgment (ACK) is received.

The requirement to experience consecutive error events before triggering a transmission rate reduction is prone to error events generated by poorly separated signal conditions and error events generated by packet collisions. It also enables rate reduction latency to be faster than the criterion considering the average number of packet error events, and provides additional transmission rate reductions when already implemented rate reductions do not result in more reliable communications.

When an acknowledgment (ACK) is determined to be received in response to the transmitted packet in step 405, the total successful packet transmission counter 120 is incremented and the individual packet transmission error counter 122 is reset to zero (step 430). Next, decide whether an increase in the transfer rate is to be expected. Generally, when the transmission rate increases, the proportion of packets transmitted that cause transmission errors also increases. The preferred transmission rate is the highest supported rate that can be used while still achieving an acceptable quality of service. For example, the quality of service can be expressed as a transmission packet error rate or a ratio of transmission errors to successful transmissions. An increase in the transmission rate may be expected if the transmitter experiences a lower ratio of transmission errors to successful transmissions than is required to maintain an acceptable quality of service.

The transmission packet error rate base process 320 can determine whether the transmission rate increase can be obtained by first summing the total successful packet transmission count and the total failed packet transmission count (that is, finding the total number of packet transmissions since the beginning of transmission or since the last packet transmission rate change) come to expect. This sum is compared to a threshold (here denoted as packets needed for rate increase) (step 435). Packets Required for Rate Increase indicates the minimum number of packets that must be transmitted since the last packet transmission rate change occurred since the rate increase was allowed. If the sum is not greater than or equal to the packets required for the rate increase, then no packet transmission rate adjustment is allowed and the packet transmission rate is not increased.

If the sum of the total successful packet transmission count and the total failed packet transmission count is greater than or equal to the packets required for the rate increase (step 435), then process 320 may determine whether the rate increase is warranted. The rate increase is whether the proportion of guaranteed transmission failures is less than that allowed to maintain the expected quality of service. For example, the proportion of transmission failures may be indicated by determining the ratio of transmission failures to successful transmissions or in any other suitable manner. The packet transmission rate increase is determined by determining whether the ratio of the guaranteed total successful packet transmission count to the total failed packet transmission count is less than that required to maintain an acceptable quality of service. The rate required to maintain an acceptable quality of service is a threshold (designated here as the rate increase rate). If the ratio of the total failed packet transmission count to the total successful packet transmission count is determined to be not less than the rate increase ratio in step 440, then the packet transmission rate increase is not guaranteed and the packet transmission rate is not adjusted.

However, if the ratio of the total failed packet transmission count to the total successful packet transmission count is determined to be less than the rate increase ratio at step 440, then the packet transmission rate increase is increased to the next highest step (i.e., the second highest supported packet transmission rate), if applicable One is obtained, and the total successful packet transmission counter 120 and the total failed packet transmission counter 124 are reset to zero (step 445). During the communication session, process 25 may be repeated until the maximum supported transmission rate is achieved or an acknowledgment (ACK) is not received.

Relative signal strength indicator processing is dynamically trained at the first station as communication occurs between the first station (where the invention is implemented) and the second station. When RSSI processing is trained, the RSSI processing preferably determines a preferred transmission rate for the first station. RSSI-based rate adaptation processing adapts the packet transmission rate at which packets are transmitted from the first station to the second station by reflecting variations in received packet power received at the first station from the second station. In an embodiment, the received power is reflected in the measured relative signal strength index of the received packets; however, signal-to-noise ratio or other metrics related to the received power may also be used.

The relative signal strength index based process dynamically correlates the transmission packet error rate of packets transmitted by the first station to the second station with the relative signal strength index of packets received at the first station from the second station. This dynamic correlation is referred to herein as a training relative signal strength indicator based process. The correlation is performed for each supported transmission rate used by the first station. It helps to separate the levels into expected ranges of received signal power. For example, if the received signal power is expected to range from -97dBm to -64dBm, the range can be easily divided into levels spaced by 3dBm; eg -97dBm to -94dBm, -94dBm to -94dBm for a total of 12 separate power levels -91dBm, ... -67dBm to -64dBm. Any received power less than -97dBm can be combined together as an additional power level, and any received power greater than -64dBm can be combined together as yet another power level. It should be understood that the range is from -97 to -64, the range is divided into levels spaced by 3dBm, and that the 12th separation level is used for illustration only and is not limiting. The transmitted packet error rate and received packet relative signal strength indicators are determined by collecting first station measurements and information for each packet transmitted from the first station to the second station and from the second station to the first station. Information collected about each packet transmitted from the first station to the second station includes the transmission rate at which the packet was transmitted and whether the transmission was successful (ACK (acknowledgement) was received) or resulted in a transmission error (ACK (acknowledgement) was not is received). From this information, the transmission packet error rate is calculated at each transmission rate used.

Information collected about each packet transmitted from the second station to the first station includes received packet signal strength measurements (eg relative signal strength pointers) and the packet was received information. Relative signal strength pointer measurements are considered valid only for a specified maximum duration. For RSSI training, it should be noted that all packet types can be used (ie DATA, ACK, RTS, CTS or similar). If more than one packet is received from the second station within the maximum duration, the process may use a relative signal strength indicator from the last received packet or calculate a statistic (eg, an average) based on a number of packets. Due to the short time between when a packet is transmitted and when an ACK is received, relative signal strength indicator measurements of ACK frames that confirm a transmitted packet in the case of a successful transmission are particularly relevant. Therefore, in the first embodiment, only the relative signal strength pointer of the ACK (acknowledgment) signal is used.

In this embodiment, the RSSI training process relates to the RSSI of each ACK (acknowledgment) received at the associated TP rate that was acknowledged. If an ACK (acknowledgement) is received, its RSSI is measured and its RSSI level is determined, then the packet transmission is attributed to the RSSI level at the used transmission rate. If no ACK (acknowledgment) is received, a transmission error is assumed. In this example, if RSSI processing is not used to select the transmission rate, then the error is not attributed to any particular RSSI level. However, if RSSI processing is used to select the transmission rate, the RSSI level used to select the transmission rate is identified, and the error is attributed to the RSSI level and transmission rate . Computing the total number of transmitted packets and transmission errors is maintained for each relative signal strength indicator level for each transmission rate. The transmission error rate for each relative SSI level and transmission rate is calculated by dividing the number of transmission errors by the number of packet transmissions for the relative SSI level and transmission rate.

FIG. 5 is a flowchart of the relative signal strength indicator training process 345 of the overall rate adaptation process 300 of FIG. 3 . Since it is determined whether the RSSI training process is first used to determine the packet transmission rate, the RSSI training process starts after the packet is transmitted (step 505). If not, it is determined whether an ACK (acknowledgment) was received in response to the transmitter packet (step 510). If it is determined at step 510 that no ACK (acknowledgment) has been received, then the transmission error cannot be attributed to a particular RSSI level, and the RSSI training process 345 terminates. If at step 510 it is determined that an ACK (acknowledgment) is received in response to the transmitted packet, then the relative signal strength indicator measurement of the ACK (acknowledgment) is retrieved from the memory 112 in the WTRU 100, the relative signal strength indicator level It is determined by the processor 108 and the RSSI level CPT counter 126 is incremented for the RSSI level (step 515).

If it is determined in step 505 that the RSSI training process was first used to determine the packet transmission rate, then the RSSI level used by the RSSI training process to determine the transmission rate is identified (step 520 ). It is then determined whether an ACK (acknowledgment) was received for the transmitted packet (step 525). If it is determined in step 525 that ACK (acknowledgment) is not received, then the relative signal strength indicator level total packet transmission counter 126 and the relative signal strength indicator level packet transmission error counter are incremented for the relative signal strength indicator level (step 530 ). If it is determined in step 525 that an ACK (acknowledgment) is received, then the relative signal strength indicator measurement system for the ACK (acknowledgment) is retrieved from the memory 112 in the WTRU 100, and the relative signal strength indicator level for the ACK (acknowledgment) is As determined by the processor 108, the RSSI level total packet transmission counter 126 is incremented for the RSSI level of the ACK (step 535).

This information is used to calculate the transmitted packet error rate at each relative signal strength indicator level for each transmission rate used (step 540). This information can be collected in a table below in Table 3, which shows the TPER vs. RSSI statistics for each transmission rate a station uses to transmit a packet instance.

Transmission power (dBm) (relative signal strength indicator level) Transmission packet error rate of different transmission rates Rate 1 (such as 1Mbps) Rate 2 (such as 2Mbps) … Rate N (such as 54Mbps) -∞ to -97 1.00 1.00 … 1.00 -97 to -94 0.64 0.92 … 1.00 -94 to -91 0.22 0.47 … 1.00 -91 to -88 0.07 0.18 … 1.00 -88 to -85 0.01 0.08 … 0.95 ... ... ... … ... -70 to -67 0.00 0.00 … 0.15 -67 to -64 0.00 0.00 … 0.03 -64 to ∞ 0.00 0.00 … 0.00

table 3

As shown in FIG. 5, the given RSSI level and transmission rate are updated after each new packet transmission (step 540). If the packet was received in error the first time it was transmitted and when it was retransmitted, the second transmission is transmitted as a unique packet. In the event of a successful transmission, the database is updated using the RSSI measurement of the ACK (acknowledgment) frame alone or in combination with the RSSI used to determine the transmission rate. If a plurality of valid relative signal strength index measurements are available, the most recent or statistical value (eg, the average of two or more recent measurements) may be used to determine the relative signal strength index level. However, relative signal strength pointer measurements of the last received ACK (acknowledgment) may be advantageously used as it is temporally close to the transmitted packet.

Relative signal strength indicator based processing also takes as input the expected target transmitted packet error rate or the maximum allowable packet error rate. The target transmitted packet error rate is the same for all transmission rates, or it varies for different rates. For example, in Table 3, the maximum allowable PER is set to 0.10 for all rates. Thus, the preferred transmission rate at any RSSI level is the highest transmission rate at that level with a TPER not greater than 0.10. For the effective transport PER, there must be a sufficient number of measurements to establish the PER.

The packet error rate received for relative SSI levels to establish the effective transmit packet error rate shall be a configurable number. For example, to establish a transmit packet error rate no greater than 0.10, at least 10 packets must be received. Alternatively, the transmit packet error rate is preferably considered stable only after a number of better packets received equal to the reverse expected multiple of the transmit packet error rate. For example, if the expected multiple is two and the target TPER value for a particular RSSI level and transmission rate is 0.10, then for the TPER value to be considered stable, at least 2x(1/10)= 20 packets must be received at the RSSI level and transmission rate.

In Table 3, the values in bold font indicate the preferred transmission rate for each relative signal strength indicator level. For example, at RSSI levels of -88dBm to -85dBm, rate 1 (1Mbps with 0.01 transmit packet error rate) and rate 2 (2Mbps with 0.08 transmit packet error rate) both have maximum allowable values below 0.10 transmission packet error rate. If the next highest rate (no icon) has a PER higher than the maximum allowable (eg, 0.15), then the preferred transmission rate is rate 2, which is the highest rate with a PER less than the maximum allowable. RSSI is very low (anything less than -91dBm in Table 3) so there is no support rate given for transmit PER statistics below the maximum allowable PER. In this example, RSSI based processing should be less It is preferable to use a flag to indicate that no supported rate yields an acceptable transmit packet error rate. In this example, the packet should not be transmitted because the transmitted packet may be more erroneous than indicated by the target or maximum allowable packet error rate. Alternatively, the preferred transmission rate can be set at the lowest supported rate before transmitting the packet. This information can be summarized in the table below, Table 4.

Transmission power (dBm) (relative signal strength indicator level) Better rate -∞ to -97 non-flag -97 to -94 non-flag -94 to -91 non-flag -91 to -88 rate 1 -88 to -85 rate 2 ... ... -67 to -64 Rate N -64 to ∞ Rate N

Table 4

As shown in FIG. 5 , the transmission packet error rate is calculated for the relative SSI level and the transmission rate, and the preferred transmission rate for the relative SSI level is also determined as above (step 540 ). After the transmission rate versus RSSI level statistics are obtained and determined to be stable for a particular RSSI level, the RSSI based process is then used to adjust the transmission rate of the transmitter. Otherwise, transmit packet error rate based processing is performed to determine the transmit rate.

6 is a flowchart of an alternative relative signal strength indicator training process 345' of the overall rate adaptation process 300, which in this example generally assumes that transmitter power and channel conditions remain substantially fixed for time intervals substantially equal to the maximum duration.

After the packet is transmitted, it is determined whether an ACK (acknowledgment) was received for the transmitted packet (step 605). If so, the RSSI measurement of the ACK (acknowledgment) signal is retrieved from the memory 112 in the WTRU 100, its RSSI level is determined, and the RSSI level transmission count is is incremented (step 610). The TPE is then updated for the RSSI level to determine whether the TPE is stable for the RSSI level, and if so, the optimal packet transmission rate for the RSSI level is updated (step 615).

If it is determined in step 605 that the transmitted packet does not receive an ACK (acknowledgment), then it is determined whether any packet received from the second station within the last maximum duration can obtain relative signal strength indicator measurements (step 620). If not, the transmission error cannot be attributed to a particular relative signal strength indicator level, and process 345' terminates. However, if it is determined at step 620 that one or more RSSI measurements are available, then the RSSI level for the measurements is determined. If more than one RSSI level is found in step 625, then the representative RSSI level is determined, and the RSSI level total packet transmission counter 126 and the RSSI level packet transmission Error counter 128 is incremented for the RSSI level. The TPEC for the RSSI level is then updated and it is determined whether the TPEC is stable for the RSSI level. If yes, the preferred packet transmission rate for the RSSI level is updated (step 615).

It should be noted that the RSSI training processes 345 and 345' are ongoing processes. Transmitted Packet Error Rate is based on Figure 5 or 6 to follow incoming packets per packet transmission, or instead after every N packets transmission, even after RSSI levels are considered "trained" Standards are updated. Old statistical values may preferably be deleted from memory 112 after a significant time interval elapses, or used by maintaining in memory only a preferred number (eg, 100) of the last measurements. Alternatively, the RSSI statistics stored in memory 112 may be flushed periodically, whereby the RSSI training process 345 and 345' restarts from zero.

In an embodiment of the invention according to FIG. 7, a first station transmitting to a second station adjusts its transmission rate in response to a rate command received from the second station. This embodiment involves measuring at the second station, determining a preferred rate, generating a rate command, sending the rate command to the first station, and implementing the preferred rate at the first station. Optionally, the measurements themselves can be transmitted to the first station, which can determine the preferred transmission rate. The measurements used to determine the preferred rate may include link quality indicators and/or other measurements such as relative signal strength indicators or signal-to-noise ratios of signals received at the second station from the first station. The rate command from the second station to the first station is preferably placed in the MAC header of the packet sent by the second station to the first station, but it can also be sent by other means, such as the frame fee or in one or more dedicated packets.

This implementation assumes that the second station has stored in memory the sensitivity (eg, signal-to-noise ratio) required to achieve a desired quality of service (eg, packet error rate) for each allowed transmission rate. The method by which this information is obtained by the second station may include pre-configuration, training or the like, and is beyond the scope of this implementation of the invention.

For every packet received by the second station from the first station (including packets addressed to nodes other than the second station), the second station measures and stores the signal-to-noise ratio of the packet and the time it was received in memory . Thereafter, whenever the second station needs to send a packet to the first station, it needs to check its memory to see if it has received any packets from the first station within the last maximum duration. If so, then the second station generates a statistic from the SNR measurement (e.g., the average SNR of packets received over a maximum duration, or the latest effective SNR, or the like) and compares it to the one stored in Sensitivity numbers in memory are compared. The preferred rate is the highest rate at which the generated SNR statistic is better than the SNR required to achieve the expected quality of service. The second station then encodes the expected rate into a rate command sent to the first station.

If the second station has not received a packet from the first station within the maximum duration, the second station can set the preferred transmission rate as the default rate; or the last rate at which it successfully received the packet; Sent to the last velocity command of the first station. Alternatively, it may transmit an indication that the second station does not offer the transmission rate that the first station should use, thus leaving it to the first station to determine its transmission rate. The second station encodes the expected rate or signal into a rate command and transmits it to the first station. The first station then stores the last speed command and the time it was received in memory and implements it when it is sent to the second station.

7 is a flowchart of a rate adaptation process 700 in which a transmission rate command is generated at the second station and transmitted to the first station. When the first station has a packet to transmit to the second station (step 705), it may check its memory 112 to see if it has received a valid rate command from the second station within the last maximum duration (step 710). If so, the first station may set its transmission rate according to the last rate command received. If no valid rate command is available, the first station may determine its own transmission rate as described above (step 720). The packet is then transmitted (step 725).

Although features and components of the present invention are described in particular combinations in preferred embodiments, each feature and component is not required for other features and components of the preferred embodiment, or with or without various features and components of the present invention. used alone in combination.

Claims (74)

1. A method for adjusting a packet transmission rate of a wireless transmission/reception unit in a wireless communication system, the wireless communication system comprising a plurality of wireless transmission/reception units, the method comprising: (a) a first one of the WTRUs determines a packet transmission rate at which packets are available for transmission; (b) the first WTRU transmits the packet to a second one of the WTRUs at the transmission rate selected in step (a); and (c) The first WTRU performs a RSSI training process based on the transmitted packet. 2. The method according to claim 1, further comprising: (d) The first WTRU determines whether at least one valid relative signal strength indicator measurement is available for at least one packet received from the second WTRU within a predetermined time interval. 3. The method according to claim 2, wherein if the determination of step (d) is affirmative, the method further comprises: (e) the first WTRU determines the relative signal strength indicator level of the at least one measurable relative signal strength indicator; and (f) The first WTRU determines whether the relative signal strength indicator level determined in step (e) is first used by the relative signal strength indicator training process within the predetermined time interval. 4. The method according to claim 3, wherein if the determination of step (f) is affirmative, the method further comprises: (g) The first WTRU sets the packet transmission rate to a preferred packet transmission rate established for the RSSI level determined according to the RSSI training process. 5. The method according to claim 2, wherein if the determination of step (d) is negative, the method further comprises: (e) The first WTRU performs a transmission packet error rate based process to determine the packet transmission rate. 6. The method according to claim 3, wherein if the determination of step (f) is negative, the method further comprises: (g) The first WTRU performs a transmission packet error rate based process to determine the packet transmission rate. 7. The method according to claim 1, wherein the relative signal strength pointer training process comprises: (i) if the second WTRU sends an acknowledgment (ACK) message to the first WTRU in response to receiving the packet transmitted by the first WTRU, then the first WTRU determines a relative signal strength indicator level for the acknowledgment (ACK) message, and increments a total packet transmission count for the relative signal strength indicator level; and (ii) The first WTRU updates a preferred packet transmission rate of the RSSI level. 8. A method for adjusting a packet transmission rate of an access point in a wireless communication system, wherein the wireless communication system comprises at least one access point and at least one wireless transmission/reception unit, the method comprising: (a) the access point determines the packet transmission rate at which an available packet is transmitted; (b) the access point transmits the packet to the WTRU at the transmission rate selected in step (a); and (c) The AP performs a RSSI training process based on the transmit packet. 9. The method of claim 8, further comprising: (d) The AP determines whether at least one valid relative signal strength indicator measurement is available for at least one packet received from the WTRU within a predetermined time interval. 10. The method according to claim 9, wherein if the determination of step (d) is affirmative, the method further comprises: (e) the access point determines the relative signal strength indicator level of the at least one active relative signal strength indicator measurement; and (f) The AP determination is determined based on whether the RSSI level determined in step (e) is first used by the RSSI training process within the predetermined time interval. 11. The method according to claim 10, wherein if the determination of step (f) is affirmative, the method further comprises: (g) The AP sets the packet transmission rate to a preferred packet transmission rate established for the RSSI level determined according to the RSSI training process. 12. The method according to claim 9, wherein if the determination of step (d) is negative, the method further comprises: (e) The access point implements a transmission packet error rate based process to determine the packet transmission rate. 13. The method according to claim 10, wherein if the determination of step (f) is negative, the method further comprises: (g) The access point performs transmission packet error rate based processing to determine the packet transmission rate. 14. The method according to claim 8, wherein the relative signal strength pointer training process comprises: (i) If the WTRU sends an acknowledgment (ACK) message to the access point in response to receiving the packet sent by the access point, the access point determines the acknowledgment (ACK) message a relative signal strength indicator level measured by a relative signal strength indicator, and a total packet transmission count incrementing the relative signal strength indicator level; and (ii) A better packet transmission rate at which the AP updates the RSSI level. 15. An access point capable of adjusting a packet transmission rate, the access point comprising: (a) a processor that determines a packet transmission rate for the access point; and (b) a transmitter that transmits a packet to a wireless transmit/receive unit at the rate determined by the processor, wherein the processor is operable to perform relative signal strength indicator training processing on the packet and may determine to Whether at least one relative signal strength indicator measurement is available for at least one packet received from the WTRU within a time interval. 16. The access point of claim 15, wherein if at least one relative signal strength indicator measurement is available for at least one packet received from the WTRU within a predetermined time interval, the processor Determining the relative signal strength indicator level of the at least one measurable relative signal strength indicator, and determining whether the relative signal strength indicator level is first used by the relative signal strength indicator training process within the predetermined time interval. 17. The access point of claim 15, wherein if at least one relative signal strength indicator measurement is not available for at least one packet received from the WTRU within a predetermined time interval, the processing The device implements a transmission packet error rate based process to determine the packet transmission rate. 18. The access point of claim 17, wherein the processor implements a transmission if the RSSI level is not previously used by the RSSI training process within the predetermined time interval Packet Error Rate is the basis for processing to determine the packet transfer rate. 19. The access point according to claim 17, wherein if the RSSI level is first used by the RSSI training process within the predetermined time interval, the processor sets the packet The transmission rate is determined based on the RSSI training process to establish a preferred level for the RSSI level. 20. The access point of claim 15, wherein if the WTRU transmits an acknowledgment (ACK) message in response to receiving the packet transmitted by the access point, the processor determines A relative signal strength pointer level for the acknowledgment (ACK) message, and a total packet transfer count for incrementing the relative signal strength pointer level, and updating a preferred relative signal strength pointer level for the acknowledgment (ACK) message Packet transfer rate. 21. The access point according to claim 15, wherein if the access point receives an acknowledgment (ACK) message for the packet in response to sending the packet, the processor determines to send the packet at the predetermined time Whether any packet received from the second WTRU within the interval can obtain any relative signal strength indicator measurement, if so, determine a relative signal strength indicator level of the packet, and increase the relative signal strength indicator level A total transfer count and an error count for , and a preferred packet transfer rate for updating the relative signal strength indicator level. 22. An integrated circuit (IC) incorporated into a transceiver for adjustable packet transmission rates of the transceiver, the integrated circuit comprising: (a) a processor that determines a packet transmission rate for the access point; and (b) a transmitter that transmits a packet to another transceiver at the rate determined by the processor, wherein the processor may apply a relative signal strength indicator training process to the packet and may determine to Whether at least one relative signal strength indicator measurement is available for at least one packet received from the other transceiver. 23. The integrated circuit of claim 22, wherein the processor determines if at least one relative signal strength indicator measurement is available for at least one packet received from the other transceiver within a predetermined time interval. A measurable relative signal strength indicator level of the relative signal strength indicator, and determining whether the relative signal strength indicator level is first used by the relative signal strength indicator training process within the predetermined time interval. 24. The integrated circuit of claim 22, wherein the processor implements a transmit packet if at least one relative signal strength indicator measurement is not available for at least one packet received from the other transceiver within a predetermined time interval The error rate is the basis for processing to determine the packet transmission rate. 25. The integrated circuit according to claim 24, wherein if the RSSI level is not first used by the RSSI training process within the predetermined time interval, the processor implements a transport packet The error rate is the basis for processing to determine the packet transmission rate. 26. The integrated circuit according to claim 24, wherein if the RSSI level is first used by the RSSI training process within the predetermined time interval, the processor sets the packet transmission The rate is a better level established for the RSSI level determined according to the RSSI training process. 27. The integrated circuit of claim 22, wherein if the other transceiver transmits an acknowledgment (ACK) message in response to receiving the packet, the processor determines a relative signal strength of the acknowledgment (ACK) message RSSI levels measured by pointers, and a total packet transfer count to increment the RSSI level, and a preferred packet transfer rate to update the RSSI level. 28. The integrated circuit of claim 22, wherein if the transceiver does not receive an acknowledgment (ACK) message for the packet in response to transmitting the packet, the processor determines the acknowledgment (ACK) message A relative signal strength indicator level for the relative signal strength indicator measurement, and a preferred packet transmission rate for updating the relative signal strength indicator level. 29. A wireless transmission/reception unit capable of adjusting a packet transmission rate of a packet transmitted by the wireless transmission/reception unit via an antenna, the wireless transmission/reception unit comprising: (a) a transmitter that transmits at least one packet to a node at a specific packet transmission rate; (b) a receiver that receives an acknowledgment (ACK) signal from the node that received and acknowledged receipt of the at least one packet; (c) a processor in communication with the transmitter and the receiver; (d) a memory in communication with the processor; (e) a transfer rate database in communication with the processor; and (f) A plurality of packet transfer counters in communication with the processor. 30. The WTRU as claimed in claim 29, wherein the specific packet transmission rate is initially set as a preset rate. 31. The WTRU of claim 29, wherein the packet transmission counter comprises a total successful packet transmission counter and an individual packet transmission error counter. 32. The WTRU of claim 31, wherein the total successful packet transmission counter is incremented when the receiver receives an acknowledgment (ACK) from the node. 33. The WTRU of claim 32, wherein the receiver resets the individual packet transmission error counter to zero when the receiver receives an acknowledgment (ACK) from the node. 34. The wireless transmit/receive unit according to claim 33, wherein the packet transmission counter further comprises a total failed packet transmission counter, and the processor uses a first count value of the total successful packet transmission counter and The specific packet transmission rate is adjusted based on the sum of a second count value of the total failed packet transmission counter. 35. The WTRU of claim 34, wherein the specific packet transmission rate is increased if the sum is greater than or equal to a predetermined packet value required for the packet transmission rate increase. 36. The WTRU as claimed in claim 35, wherein if the ratio of the second count value to the first count value is less than a predetermined packet transmission rate increase ratio, the specific packet transmission rate is increased by Increase. 37. The WTRU of claim 29, wherein the packet transmission counter comprises a total failed packet transmission counter and an individual packet transmission error counter. 38. The WTRU of claim 37, wherein when the receiver does not receive an acknowledgment (ACK) from the node when transmitting the at least one packet to the node, the total failure packet The transmit counter and the individual packet transmit error counter are incremented. 39. The WTRU of claim 38, wherein the specific packet transmission rate is based on a count value of the individual packet transmission error counter, one or more specified by the transmission rate database supported rate steps down. 40. The WTRU as claimed in claim 29, wherein the PT counter comprises a RSSI level total PT counter. 41. The wireless transmit/receive unit according to claim 40, wherein if a relative signal strength indicator training process is not firstly used to determine the specific packet transmission rate, then automatically after transmitting the at least one packet to the node The memory is retrieved from the relative signal strength pointer measurement of an acknowledgment (ACK) received by the node, the relative signal strength pointer measure is determined by the processor, and the relative signal strength pointer bit of the relative signal strength pointer level The quasi-total packet transfer counter is incremented. 42. The wireless transmission/reception unit according to claim 41, wherein the packet error rate of the relative signal strength pointer level is updated in the memory, and if the packet error rate is stable, the relative signal strength A preferred packet transfer rate for the pointer level is also updated in the memory. 43. The wireless transmit/receive unit according to claim 40, wherein if a relative signal strength indicator training process is first used to determine the specific packet transmission rate, after transmitting the at least one packet to the node, automatically The memory is retrieved from a relative signal strength pointer measurement of an acknowledgment (ACK) received by the node, the relative signal strength pointer measure determined by the processor, and the relative signal strength pointer level of the relative signal strength pointer level The total packet transfer counter is incremented. 44. The wireless transmission/reception unit according to claim 43, wherein the packet error rate of the relative signal strength indicator level is updated in the memory, and if the packet error rate is stable, the relative signal strength A preferred packet transfer rate for the pointer level is also updated in the memory. 45. The WTRU of claim 40, wherein if a RSSI training process is first used to determine the specific packet transmission rate, an acknowledgment (ACK) is not received from the node After the at least one packet is transmitted to the node, the RSSI level total packet transmission counter of the RSSI level is incremented. 46. The wireless transmission/reception unit according to claim 45, wherein the packet error rate of the relative signal strength indicator level is updated in the memory, and if the packet error rate is stable, the relative signal strength A preferred packet transfer rate for the pointer level is also updated in the memory. 47. The WTRU as claimed in claim 29, wherein the PT counter comprises a RSSI level total PT counter and a RSSI level PT error counter. 48. The WTRU of claim 47, wherein after transmitting the at least one packet to the node, relative signal strength indicator measurements of an acknowledgment (ACK) received from the node are retrieved From the memory, the RSSI level total packet transfer counter of the RSSI level is incremented for the RSSI level of the acknowledgment (ACK). 49. The WTRU of claim 47, wherein, after the at least one packet is transmitted to the node without receiving an acknowledgment (ACK) from the node, it is determined that a final maximum duration Whether any packet received from the node during the period can obtain any relative signal strength indicator measurement, and if so, determine the relative signal strength indicator level of the measurement, and the relative signal strength indicator level total packet transmission counter and the relative signal strength indicator level The signal strength indicator level packet transmission error counter is incremented. 50. The wireless transmit/receive unit according to claim 49, wherein the packet error rate of the relative signal strength pointer level is updated in the memory, and if the packet error rate is stable, the relative signal strength indicator A preferred packet transmission rate for the strength pointer level is also updated in the memory. 51. The wireless transmission/reception unit according to claim 29, wherein the wireless transmission/reception unit sets the specific packet transmission rate based on a rate command received from the node, and based on the received The rate command is the basis for sending packets. 52. An integrated circuit incorporated into a wireless transmit/receive unit, the integrated circuit capable of adjusting a packet transmission rate of packets transmitted by the wireless transmit/receive unit via a day wire, the integrated circuit comprising: (a) a transmitter that transmits at least one packet to a node at a specific packet transmission rate; (b) a receiver for receiving an acknowledgment (ACK) signal from the node receiving and acknowledging receipt of the at least one packet; (c) a processor in communication with the transmitter and the receiver; (d) a memory in communication with the processor; (e) a transfer rate database in communication with the processor; and (f) A plurality of packet transfer counters in communication with the processor. 53. The integrated circuit of claim 52, wherein the specific packet transmission rate is initially set to a predetermined rate. 54. The integrated circuit of claim 52, wherein the packet transmission counter comprises a total successful packet transmission counter and an individual packet transmission error counter. 55. The integrated circuit of claim 54, wherein the total successful packet transmission counter is incremented when the receiver receives an acknowledgment (ACK) from the node. 56. The integrated circuit of claim 55, wherein the receiver resets the individual packet transmission error counter to zero when the receiver receives an acknowledgment (ACK) from the node. 57. The integrated circuit according to claim 56, wherein the packet transmission counter further comprises a total failed packet transmission counter, and the processor uses a first count value of the total successful packet transmission counter and the total failure The specific packet transmission rate is adjusted based on the sum of a second count value of the packet transmission counter. 58. The integrated circuit of claim 57, wherein the specific packet transmission rate is increased if the sum is greater than or equal to a predetermined packet value required for a packet transmission rate increase. 59. The integrated circuit of claim 58, wherein the specific packet transmission rate is increased if the ratio of the second count value to the first count value is less than a predetermined packet transmission rate increase ratio. 60. The integrated circuit of claim 52, wherein the packet transmission counter comprises a total failed packet transmission counter and an individual packet transmission error counter. 61. The integrated circuit according to claim 60, wherein when the receiver does not receive an acknowledgment (ACK) from the node when transmitting the at least one packet to the node, the total failed packet transmission counter and The individual packet transmission error counter is incremented. 62. The integrated circuit of claim 61, wherein the specific packet transmission rate is based on a count value of the individual packet transmission error counter, supported by one or more specified by the transmission rate database The rate step is reduced. 63. The integrated circuit of claim 52, wherein the packet transfer counter comprises a RSSI level total packet transfer counter. 64. The integrated circuit according to claim 63, wherein if a relative signal strength indicator training process is not first used to determine the specific packet transmission rate, then transmitting the at least one packet from the memory to the node RSSI measurement retrieval of an acknowledgment (ACK) received by a node, the RSSI measurement is determined by the processor, and the RSSI level total packet transmission counter of the RSSI level is Increase. 65. The integrated circuit according to claim 64, wherein the packet error rate of the relative signal strength pointer level is updated in the memory, and if the packet error rate is stable, the relative signal strength pointer level A preferred packet transmission rate of is also updated in the memory. 66. The integrated circuit according to claim 63, wherein if a relative signal strength pointer training process is first used to determine the specific packet transmission rate, after transmitting the at least one packet to the node, from the memory An RSSI measurement retrieval of an acknowledgment (ACK) received by the node, the RSSI measurement is determined by the processor, and the RSSI level of the RSSI level total packet transmission The counter will increment. 67. The integrated circuit as claimed in claim 66, wherein a packet error rate of the relative signal strength indicator level is updated in the memory, and if the packet error rate is stable, the relative signal strength indicator level is A preferred packet transmission rate of is also updated in the memory. 68. The integrated circuit of claim 63, wherein if the RSSI training process is first used to determine the specific packet transmission rate, the at least After a packet is transmitted to the node, the RSSI level total packet transmission counter of the RSSI level is incremented. 69. The integrated circuit according to claim 68, wherein the packet error rate of the relative signal strength pointer level is updated in the memory, and if the packet error rate is stable, the relative signal strength pointer level A preferred packet transmission rate of is also updated in the memory. 70. The integrated circuit of claim 52, wherein the packet transmission counter comprises a RSSI level total packet transmission counter and a RSSI level packet transmission error counter. 71. The integrated circuit of claim 70, wherein relative signal strength pointer measurements of an acknowledgment (ACK) received from the node after transmitting the at least one packet to the node are retrieved from the memory , and the RSSI level total packet transmission counter of the RSSI level is incremented for the RSSI level of the acknowledgment (ACK). 72. The integrated circuit of claim 70, wherein after transmitting the at least one packet to the node without receiving an acknowledgment (ACK) from the node, it is determined to send the packet from the node within a last maximum duration Whether any packet received by the node can obtain any relative signal strength indicator measurement, and if so, determine the relative signal strength indicator level of the measurement, and the relative signal strength indicator level is the total packet transmission counter and the relative signal strength indicator bit The quasi-packet transmission error counter is incremented. 73. The integrated circuit according to claim 72, wherein the packet error rate of the relative signal strength pointer level is updated in the memory, and if the packet error rate is stable, the relative signal strength pointer level A preferred packet transmission rate of is also updated in the memory. 74. The integrated circuit of claim 52, wherein the integrated circuit sets the specific packet transmission rate based on a rate command received from the node, and transmits packets based on the received rate command .

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