CN1918864A - Qos management for multiple service instances - Google Patents

Abstract

In a mobile communication network, a desired rate needed to maintain a desired quality of service for each service instance is computed and the individual rates for all service instances are summed to get an aggregate rate needed to maintain the desired quality of service for all service instances. A rate determination is made based on the aggregate rate.

Description

Quality of Service Management for Multiple Service Instances

technical field

The present invention relates generally to high rate packet data services for mobile communications, and more particularly to methods of controlling the rate of data transmission on a forward or reverse link channel to maintain a desired quality of service.

Background technique

Currently deployed third-generation wireless networks provide high-speed data services on forward and reverse channels. However, these services are best effort services without any Quality of Service (QoS) guarantees. QoS is the guarantee that a network meets a predetermined set of service performance constraints such as throughput, rate, end-to-end delay, jitter, and probability of packet loss. QoS guarantees are traditionally obtained through resource reservation. Establish connections with end users and reserve capacity, and reserve resources to send data packets to users to ensure quality of service. In wireless networks, the resources needed to satisfy QoS constraints are constantly changing due to the mobility of mobile stations.

Recent revisions to the 1XEV-DV standard include the implementation of QoS restrictions and enhancements that enable operators to provide QoS guarantees to mobile users. Similar features are included in 1XEV-DO and WCDMA. These enhancements allow operators to guarantee service performance for application requirements such as realistic throughput, jitter, latency and bit error rate. Users can run multiple QoS-based applications at the same time. Each is backed by a corresponding service instance distinguished by its service identification number.

In the 1XEV-DV revision D standard, each mobile station reports information (buffer occupancy rate and power headroom) of each service instance (SI) to the base station. These reports can be triggered by certain events, such as queue length thresholds, or can be sent periodically. The base station uses this information to determine the appropriate rate to allocate to the mobile station.

Reporting of power headroom and buffer level is done separately for each SI. Therefore, the signaling required to satisfy QoS guarantees increases with the number of service instances. Since the mobile station often has multiple concurrent SIs, it is desirable to reduce the signaling overhead required to ensure QoS, so that system resources will not be pressured by additional signaling loads.

Contents of the invention

The present invention provides methods and apparatus for controlling data transmission rates to meet desired quality of service (QoS). The rate required to satisfy the desired quality of service is determined separately for each of the plurality of application or service instances. The expected rates for each application or service instance are then summed to determine the aggregate rate for all application or service instances. Rate determination is done based on the aggregate rate. The present invention can be used to control the data transmission rate on forward and reverse packet data channels.

The invention may eg be implemented in a mobile station for controlling the data transmission rate of the mobile station on a reverse packet data channel. In this embodiment of the invention, the mobile station calculates the service rate required to maintain the desired quality of service for each service instance, and sums the desired rates to calculate the aggregate rate for all application or service instances. The mobile station then determines the expected transmission rate of the R-PDCH according to the aggregate rate required to maintain the expected service quality of all applications or service instances, and sends a rate request to the base station. The desired transmission rate can be determined by mapping the aggregated rate to the closest allowed rate. If the aggregated rate exceeds the maximum allowed rate, the mobile station requests the maximum rate. If the mobile station does not have sufficient power to transmit at the rate required to maintain the desired quality of service, the mobile station adjusts the rate request down to a level achievable by the mobile station taking into account the available power.

In another aspect of the invention, the mobile station may oscillate the rate at a predetermined control period to achieve an effective rate approximately equal to the aggregated rate. A mobile station can change its transmission rate between two or more selected rates in a single rate control cycle. In one embodiment of the invention, the mobile station transmits at a first rate for a predetermined number of frames and transmits at a second rate for the remaining frames during a rate control period. This idea can be extended to three or more rates.

Description of drawings

Figure 1 is a block diagram illustrating logical elements of an exemplary mobile communication network according to the present invention;

Figure 2 is a block diagram of an exemplary base station of a mobile communication network according to the present invention;

Figure 3 is a block diagram of an exemplary mobile station according to the present invention;

4 is a flowchart of an exemplary process performed by a mobile station.

Detailed ways

1 illustrates the logical entities of an exemplary wireless communication network 10 that provides packet data services to mobile stations 12. As shown in FIG. The wireless communication network 10 is a packet-switched network, such as a CDMA network, a WCDMA network, an EDGE network or a UMTS network. Figure 1 illustrates a wireless communication network 10 configured according to the cdma2000 (IS2000) standard. The wireless communication network 10 includes a packet-switched core network 20 and a radio access network (RAN) 30 . The core network 20 includes a Packet Data Serving Node (PDSN) 22 , which is connected to an external Packet Data Network (PDN) 16 , such as the Internet, and supports a PPP connection for the mobile station 12 . The core network 20 adds and deletes IP flows to the RAN 30 and routes packets between the external packet data network 16 and the RAN 30. The RAN 30 is connected to the core network 20 and provides access to the mobile stations 12 of the core network 20.

The RAN 30 includes a Packet Control Function (PCF) 32, one or more Base Station Controllers (BSC) 34, and one or more Radio Base Stations (RBS) 36. The primary function of the PCF 32 is to establish, maintain and terminate connections to the PDSN 22. BSCs 34 manage radio resources within their respective coverage areas. The RBS 36 includes radio equipment for communicating with the mobile station 12 over the air interface. A BSC 34 may manage more than one RBS 36. In a cdma2000 network, BSC 34 and RBS 36 include base station 40 (FIG. 2), described in more detail below. The BSC 34 is the control part of the base station 40. RBS 36 is the part of base station 40 that includes radio equipment and is typically associated with a cell site. In a cdma2000 network, a single BSC 34 may include the control portions of multiple base stations 40. In other network architectures based on other standards, the network components making up base station 40 may be different, but the overall functionality will be the same or similar.

Figure 2 illustrates exemplary details of a base station in a cdma2000 network. In the exemplary embodiment, base station components are distributed between RBS 36 and BSC 34. The RBS 36 includes RF circuitry 42, baseband processing circuitry and control circuitry 44, and interface circuitry 46 for communication with the BSC 34. The baseband processing and control circuitry includes a rate controller 60, described further below. Rate controller 60 schedules the data transmission rate for mobile station 100 on a Reverse Packet Data Channel (R-RPDCH), described more fully below. Baseband processing and control circuitry 44 may include one or more processors. The BSC 34 includes an interface circuit 48 communicating with the RBS 36, a communication control circuit 50, and an interface circuit 54 communicating with the PCF 32. The communication control circuit 50 manages the radio and communication resources used by the base station 40 . The communication control circuit 50 may include one or more processors programmed to perform the functions of the communication control circuit 50 .

Revisions C and D of the cdma200 standard, generally referred to as 1xEV-DV, introduce forward and reverse packet data channels designed for high-speed packet data communications far beyond those currently available in cdma2000 1x networks. The IxEV-DV standard also includes enhancements that make it possible for network operators to provide quality of service (QoS) guarantees to subscribers. The invention is described below in the context of controlling the data transmission rate of a mobile station 100 on a reverse packet data channel in order to maintain a desired quality of service. Those skilled in the art will appreciate that the present invention is equally applicable to controlling the data transmission rate on the forward packet data channel.

R-PDCH is divided into 10ms frames. The mobile station transmits data packets in frames ranging from 192 bits to 18432 bits. The 10 ms frame duration combined with the variable packet size allows the mobile station 100 to obtain data transfer rates ranging from 6.4 kbps to 18432 kbps. In order to solve the QoS of the reverse link, the cdma2000 standard defines an autonomous transmission mode, which allows the mobile station 100 to start data transmission up to a specified maximum autonomous rate at any time, thereby reducing delay. Once the mobile station 100 has started transmitting, the mobile station 100 is allowed to vary its data transmissions depending on factors such as channel conditions of the mobile station 100, power availability, QoS restrictions, buffer levels on the mobile station, and load levels on the base station 40 rate.

In a cdma2000 network, the mobile station 100 reports its buffer level and power availability to the base station 40 for each service instance (SI) through a reverse request channel (R-REQCH). The rate controller 60 on the base station 40 determines the data transmission rate of the mobile station 100 satisfying the QoS guarantee according to the report from the mobile station 100 . If the mobile station 100 has many SIs, the signaling overhead to satisfy the QoS guarantees can consume a lot of reverse link bandwidth. The present invention reduces the signaling required to maintain the desired QoS on the R-PDCH.

According to the present invention, the mobile station 100 determines the aggregate rate required to maintain the desired QoS for all SIs. It is assumed that a single reverse link channel is used for all SIs. The aggregate rate is calculated by determining the desired rate for each SI to maintain the specified QoS constraints, and summing the individual rates for each SI to obtain the aggregate rate. The mobile station 100 requests the desired rate based on the aggregated rate. Base station 40 receives the rate request and rates mobile station 100 according to the requested rate. Since the mobile station 100 sends a single rate request for all service instances, signaling overhead is greatly reduced.

The following model provides the basis for calculating the rate each application needs to maintain its QoS guarantees. It is assumed that the IP packet of each SI is divided into a plurality of RLP (Radio Link Protocol) frames and set at the end of its RLP buffer. RLP frames in this buffer are served in a first in first out (FIFO) fashion. If the transmission of the RLP frame fails, it is retransmitted at the physical layer. This operation is repeated a specified number of times as necessary. Such RLP frames are placed in the retransmission buffer and are strictly given higher service priority than new frame transmissions.

A physical layer frame consists of one or more RLP frames. The number of data bits per physical layer frame depends on the reverse link rate of the mobile station. If the first transmission of a physical layer frame is unsuccessful, it is retransmitted up to a maximum number of two retransmissions. These retransmissions are combined with earlier transmissions (soft combining) in order to increase the probability of success. The transmission power for each transmission is varied such that the remaining FER (after all transmissions) is at most 1%. Note that 1% failures are retransmitted at the RLP layer, but with a new round of physical layer transmission.

Periodically (taking a period τ assumed to be a multiple of the frame duration), the mobile station 100 counts the number _bi (n) of information bits that left the original transmission queue for SIi during period n (the previous period). Also determine the size q _i (n) of this queue (in units of information bits). The rate at which filtered information bits leave the raw transmit buffer for a given SI is given by:

${\mathrm{\μ}}_i\left(\mathrm{no}\right)={\mathrm{\α}}_{\mathrm{\μ}}\frac{b_i\left(\mathrm{no}\right)}{\mathrm{\τ}}+(1-{\mathrm{\α}}_{\mathrm{\μ}}){\mathrm{\μ}}_i(\mathrm{no}-1)$ Equation (1)

where α _μ is the corresponding filter constant and μ _i (0)=0.

The number of information bits arriving in the same period is given by _bi (n)+q _i (n)-q _i (n-1). Therefore, the filtered information bit arrival rate is given by:

${\mathrm{\λ}}_i\left(\mathrm{no}\right)={\mathrm{\α}}_{\mathrm{\λ}}\frac{b_i\left(\mathrm{no}\right)+q_i\left(\mathrm{no}\right)-q_i(\mathrm{no}-1)}{\mathrm{\τ}}+(1-{\mathrm{\α}}_{\mathrm{\λ}}){\mathrm{\λ}}_i(\mathrm{no}-1)$ Equation (2)

where α _λ is the corresponding filtering time constant, and λ _i (0)=0.

For calculating the expected rate, it is assumed that each RLP frame leaving the original transmit queue eventually reaches the base station 40 successfully. In other words, we assume an unlimited number of RLP retransmissions. Under this assumption, this information bit departure rate, denoted μ _i , is equal to the actual throughput g _i of the channel, since it is the rate at which frames are successfully received. If we denote by ρ the overhead incurred when transmitting an RLP frame over the air interface (due to physical and RLP layer retransmissions), the following relation holds:

μ _i ＝(1-ρ)r _i Equation (3)

Therefore, at the end of period n, we can estimate ρ(n) as follows:

$\mathrm{\ρ}\left(\mathrm{no}\right)={\mathrm{\α}}_{\mathrm{\ρ}}(1-\frac{{\mathrm{\Σ}}_i{\mathrm{\μ}}_i\left(\mathrm{no}\right)}{R\left(\mathrm{no}\right)})+(1-{\mathrm{\α}}_{\mathrm{\ρ}})\mathrm{\ρ}(\mathrm{no}-1)$ Equation (4)

where α _ρ is a filter constant, ρ(0)=0, and $R\left(\mathrm{no}\right)={\mathrm{\Σ}}_i{r}_i\left(\mathrm{no}\right)$ is the reverse link rate. This overhead estimate p(n) will be used by all SIs to calculate the expected service rate for each serving SI. The actual throughput g _i (n) of SIi in cycle n is estimated according to:

g _i =(1-ρ(n))r _i (n) Equation (5)

At the beginning of control period n, we assume that SIi requires rate to maintain the QoS constraints, and the rate r _i (n) is allocated by the base station 40 for subsequent control periods (after some delay). r _i (n) and The difference between is because of the unlimited number of rates supported by reverse. At each decision point (i.e., every τ seconds), the goal is to determine the service rate It should be applied in subsequent intervals such that at the end of interval n+1 the expected value of the QoS attribute involved is equal to the expected value. Note that this is calculated for each SI, so the request sent to base station 40 is obtained by summing all SIs. The model described above may be used by the mobile station 100 to calculate the expected rate for a given SI based on various QoS guarantees including actual throughput guarantees, jitter guarantees, delay guarantees, frame error rate (FER) guarantees, or other guarantees. The calculation of the expected rate of SI is discussed below.

Actual Throughput Guaranteed

Many applications require some minimum practical throughput for acceptable performance. It is not enough to provide a constant rate corresponding to the desired actual throughput, because there will be some transmission errors. If the channel frame error rate increases, the rate must also increase in order to maintain the specified actual throughput.

The mobile station 100 calculates the service rate required to keep the actual throughput g at the desired minimum value If more resources than needed are provided, the resulting system capacity (number of supported users) will be reduced. Therefore, it is assumed that SI is served at the minimum rate required to maintain the desired actual throughput g.

Recall that an estimate of the actual throughput is given by the information bit departure rate μ _i (n), which is known. The overhead estimate ρ(n) can be calculated according to Equation 5. In order to calculate the desired rate for the next rate control interval The cost ρ(n) of the current cycle is used to approximate the cost ρ(n+1) in the subsequent cycle. Therefore, the actual throughput of subsequent rate control cycles to maintain the desired QoS is approximated by:

$g=(1-\mathrm{\ρ}\left(\mathrm{no}\right))\tilde{r}(\mathrm{no}+1)$ Equation (6)

Solving Equation 6 to get the desired rate have to:

$\tilde{r}(\mathrm{no}+1)=\frac{g}{1-\mathrm{\ρ}\left(\mathrm{no}\right)}$ Equation (7)

当FER增加时，ρ(n)(在等式4中给出)增加，因为需要更多重传(在物理和RLP层)。这引起所请求速率的增加以便补偿误码，从而保持相同的实际吞吐量。Note that the actual throughput g is given, and the overhead ρ(n) is known. Therefore, Equation 7 can be used to calculate the expected rate for a given SI

When FER increases, ρ(n) (given in Equation 4) increases because more retransmissions (at physical and RLP layers) are required. This causes the requested rate to be increased in order to compensate for bit errors, thereby maintaining the same actual throughput.

Jitter guarantee

的确定，使得在间隔 结束时的延迟的预计值等于d_T。In the case of jitter guarantees, the total delay (queuing and transmission) should be kept at some specified target value d _T . Therefore, the target becomes the rate of the next interval

determined such that in the interval The expected value of the delay at the end is equal to d _T .

The expected queue size at the end of the interval q(n+1) corresponding to this delay _dT is given by _dTμ (n+1). The expected queue dynamics during the interval is given by:

q(n+λ(n)τ-μ(n+1)τ=d _T μ(n+1) Equation (8)

The bit departure rate μ(n+1) for the subsequent rate control interval is given by:

$\mathrm{\μ}(\mathrm{no}+1)=(1-\mathrm{\ρ}\left(\mathrm{no}\right))\tilde{r}(\mathrm{no}+1)$ Equation (9)

求解，得：In Equation 9, the cost of the current cycle is used to approximate the cost of the subsequent cycle as previously described. Substituting equation (9) into equation (8) and

Solving, get:

$\tilde{r}(\mathrm{no}+1)=\frac{q\left(\mathrm{no}\right)+\mathrm{\λ}\left(\mathrm{no}\right)\mathrm{\τ}}{(1-\mathrm{\ρ}\left(\mathrm{no}\right))(\mathrm{\τ}+d_T)}$ Equation (9) Note that the expected rate increases as expected with increasing queue length, arrival rate and overhead.

delay guarantee

In the case of a maximum delay guarantee, the delay should be kept below some specified value d _MAX . As long as the queuing delay is below this value, it is best to keep the rate close to the arrival rate so that the queuing delay does not increase. As the delay approaches _dMAX , the rate should increase accordingly.

This problem is similar to the case of jitter guarantees. In this case we can assume a target value d _T =0. However, unlike the jitter case, it is not critical to have the latency reach this value in a single interval. In fact, our target time in the future for the latency to reach zero should depend on how close the current latency is to the maximum value. If it's very close to the maximum, the latency should decrease rapidly (say within an interval). If the latency is already close to zero, it should reach zero more slowly.

The target time T for the current delay to reach zero can be calculated as the ratio of the maximum delay d _MAX to the current estimate d(n) of the queuing delay, ie d _MAX /d(n). A current estimate of the queuing delay can be obtained by dividing the buffer occupancy q(n) by the bit departure rate μ(n), ie d(n)=q(n)/μ(n). Therefore, the target time T is given by:

T=d _MAX μ(n)/q(n) Equation (10)

Substituting Equation 10 into Equation 9, and using the fact that d _τ = 0, we get:

$\tilde{r}(\mathrm{no}+1)=\frac{q\left({\mathrm{no}}^2\right)+\mathrm{\λ}\left(\mathrm{no}\right)\mathrm{\μ}\left(\mathrm{no}\right)d_{\max }}{(1-\mathrm{\ρ}\left(\mathrm{no}\right))d_{\max }\mathrm{\μ}\left(\mathrm{no}\right)}$ Equation (11)

随着缓冲器占用率和位到达速率增加而增加，以及随着位离开速率增加而减小。Note that, as expected, the requested rate

Increases with buffer occupancy and bit arrival rate, and decreases with bit departure rate.

Each mobile station 100 typically allocates a limited size buffer to each SI. This buffer is not large enough to support applications with large latency thresholds running at very high reverse link rates. Since the rate allowed to the mobile station 100 is not exactly what is desired, it is possible that in subsequent cycles the buffer may overflow or underflow. However, it is easy to predetermine this situation. Once the mobile station 100 determines the rate to be allowed by the base station 40, the queue length at the end of the subsequent control period can be predicted. If it is larger than the buffer size, the requested rate should be adjusted up, and if the predicted queue length is negative, the requested rate should be adjusted down. The goal is to reduce the occurrence of buffer overflow and underflow.

Fer Guarantee

Some applications may require packet loss to be kept below a minimum IP packet loss rate. If packet delivery delay guarantees are not required, this can be provided by an appropriate number of RLP retransmissions. However, if packet latency is also a concern, then FER reduction should be done at the physical layer, since less delay is incurred. Since soft reassembly is performed at the physical layer, the success probability of an additional physical layer retransmission is much higher than the success probability of the first physical layer transmission of a subsequent round of RLP. Furthermore, the additional delay incurred in the physical layer case is much smaller than in the RLP retransmission case.

Physical layer FER can be reduced by increasing the maximum number of H-ARQ retransmissions. However, this also causes increased latency. In order to maintain the same delay, the power allocated for each frame transmission can be increased (power boosted), so that the SNR of the received signal increases, thus reducing the bit error rate. This method is suggested in the 1XEV-DV standard.

As described above, the mobile station 100 calculates the expected rate of each SI based on the QoS guarantee of the SI, and adds them to obtain the expected aggregate rate. Since the reverse link only supports a limited set of rates (i.e., 19.2, 40.8, 79.2, 156.0, 309.6, 463.2, 616.8, 924.0, 1231.2, 1538.4, and 1845.6 kbps), the mobile station's desired aggregate rate must be mapped to the available rate one. One solution is to map the aggregate rate to the closest supported rate. Alternatively, the mobile station 100 may map the aggregated rate to the next higher supported rate, or to the next lower supported rate.

Since successive support rates differ by a factor of two, the resulting control will tend to have large swings. According to one embodiment of the invention, an effective rate approximately equal to the desired sum rate may be obtained by oscillating the rate during a predetermined rate control period. Assume that the rate control period consists of K frames. Assume that the desired aggregate rate of the rate control cycle is R, and denote the minimum supported rate above R and the maximum supported rate below R by _Rh and _Rl , respectively. There exists 0≦β≦1 such that R=βR _l (1−β)R _h . If mobile station 100 transmits a portion of the K frames at rate _R1 and the remainder at rate _Rh , an effective rate approximately equal to the desired aggregate rate is obtained.

If f represents the integer closest to βK, mobile station 100 may send a request message to base station 40 containing _R1 and f. If the base station 40 grants the request, the mobile station 100 transmits the first f frames at rate _R1 during the corresponding rate control period, while the remaining subsequent new frame transmissions are sent at rate _Rh .

In practice, it takes some finite period of time for the mobile station to determine the desired aggregate rate and send a rate request to the base station 40 . The base station 40 then has to determine what rate to allocate and sends back an allow message to the mobile station 100 . This signaling takes about 40ms. To account for feedback and signaling delays, estimates of μ, λ, q, ρ, etc. are computed every τ, as previously described. However, knowing that the new rate will take effect at some future time T, the queue length at future time T According to the following formula to predict:

$\tilde{q}=\max \{0,q+(\mathrm{\λ}-\mathrm{\μ})T\}$ Equation (12)

where λ and μ are estimates made when calculating the rate request (ie, assuming they do not change over the time period T). predict queue length can be used in place of q and perform the same calculation as before.

There may be some cases where the QoS guarantees cannot be satisfied in a given rate control period. Mobile station 100 is typically limited by one of three factors: maximum and minimum supportable rates, its maximum transmit power (200 mW), and reverse link interference. The QoS requirements cannot be met where the aggregate rate required to maintain the QoS guarantee exceeds the maximum transfer rate of the mobile station 100 . In this case, the mobile station 100 should request the maximum rate.

Transmit power limitations of the mobile station 100 may also prevent QoS guarantees from being met. The mobile station 100 becomes power limited when it is in poor radio conditions but its application has high resource requirements. It cannot transmit at its desired rate due to lack of transmit power. Therefore, when making a rate request decision, the mobile station 100 should first determine whether its available power supports the requested rate. If not, it should request the highest rate that can be supported by its available power. Therefore, this decision is local to the mobile station 100 and does not need to report the power information to the base station 40 .

If the reverse link interference is high, the base station 40 may not be able to allow the rate requested by the mobile station 100, which means that the base station 40 may not be able to guarantee the QoS it originally agreed upon. In this case, the reverse link is overloaded.

Figure 3 illustrates exemplary details of a mobile station 100 in accordance with the present invention. Mobile station 100 includes RF section 110 , baseband processing and control circuitry 120 , memory 130 , user interface 140 and audio circuitry 150 . RF section 110 provides a radio interface for communication with base stations. RF section 110 includes transmitter 112 and receiver 114 coupled to common antenna 118 through RF switch 116 . Transmitter 112 modulates the transmit signal onto an RF carrier and amplifies the transmit signal for transmission to base station 40 . Receiver 114 filters, amplifies and downconverts the received signal to baseband for processing by baseband processing and control circuitry 120 .

The baseband processing and control circuit 120 performs baseband processing on signals transmitted and received by the mobile station 100 and controls the overall operation of the mobile station 100 . Baseband processing and control circuitry 120 may include one or more processors, hardware, firmware, or combinations thereof. Baseband processing and control circuitry 120 includes a rate calculator 122 that determines the desired rate for each SI, calculates the aggregate rate for all SIs, and determines the requested rate, as described above.

The memory 130 stores programs and data used by the baseband processing and control circuit 120 . The memory 130 may also store user application programs. Memory 30 may include one or more storage devices, and may include random access memory (RAM) and read only memory (ROM). Computer programs and data required for the operation of the device are stored in non-volatile memory such as EPROM, EEPROM and/or flash memory. The storage device may be implemented as a discrete device, a stacked device, or integrated with the processor in the baseband processing and control circuit 120 .

User interface 140 includes one or more input devices 142 and a display 144 . Input devices may include keypads, joystick controls, touch pads, dials, or other known types of input devices. Display 144 may include a conventional LCD, or may include a touch screen display that also serves as input device 142 .

Audio circuitry 150 includes audio processing circuitry 152 , microphone 154 and speaker 156 . Audio processing circuitry 152 includes: a D/A converter for converting digital audio into an analog signal suitable for output to speaker 156; Control circuit 120 for digital audio. Microphone 154 converts the user's voice and other audible signals into electrical audio signals, and speaker 156 converts analog audio signals into audible signals that can be heard by the user.

FIG. 4 is a flowchart illustrating the rate control process 200 performed by the mobile station 100. As shown in FIG. Rate control process 200 is performed for each rate control period, which may be one or more frames. The mobile station 100 calculates the expected rate R for each application or service instance (SI) (block 202) and sums the expected rates for all SIs to obtain an aggregated rate (block 204). After determining the aggregate rate, the mobile station 100 determines the requested rate based on the aggregate rate (block 206). As previously described, the mobile station 100 can select the closest supported rate, the next higher supported rate, or the next lower supported rate. Alternatively, the mobile station may determine the rate pair { _Rl , _Rh } that yields an effective rate approximately equal to the aggregate rate during the rate control period. The mobile station 100 then sends a rate request to the base station (block 208). If a fixed rate is requested, the rate request includes the desired fixed rate. In an embodiment where the mobile station 100 alternates between two rates in order to obtain a rate desired effective rate during the rate control period, the mobile station 100 sends a rate request to the base station 40 indicating the rate it will use during the rate control period and the rate in which it will use the rate. Frames at those rates will be used. For example, a rate request may specify a rate and the number of frames that will use the specified rate. The mobile station 100 then transmits at the specified rate for the specified number of frames and then switches to the next higher or lower rate for the remaining frames.

In any case, it should be understood by those skilled in the art that the present invention is not limited by the foregoing discussion, nor is it limited by the accompanying drawings. Instead, the present invention is limited only by the following claims and their reasonable legal equivalents.

Claims (22)

1. method of controlling the message transmission rate of travelling carriage in the cordless communication network and the transfer of data between the base station, described method comprises:

The required estimated data's speed of desired service quality that keeps this Service Instance for each calculating of a plurality of Service Instances;

The data rate of all Service Instances is determined to keep mutually the required aggregate rate of described desired service quality of all Service Instances; And

Determine the transmission rate of the transfer of data between described travelling carriage and the described base station according to described aggregate rate.

2. method of rate control as claimed in claim 1, wherein, described transmitted data rates is selected from the admissible rate calendar according to the required aggregate rate of described desired service quality that keeps all Service Instances.

3. method of rate control as claimed in claim 2, wherein, described transmission rate is more than or equal in the admissible rate of the required aggregate rate of the described desired service quality that keeps all Service Instances immediate one.

4. method of rate control as claimed in claim 2, wherein, described transmission rate is to be less than or equal in the admissible rate of the required aggregate rate of the described desired service quality that keeps all Service Instances immediate one.

5. method of rate control as claimed in claim 1, wherein, described aggregate rate is used for determining the effective speed in predetermined control cycle.

6. method of rate control as claimed in claim 5, wherein, the described rate controlled cycle comprises a plurality of frames, the transmission rate of each frame is selected to obtain the effective speed of described control cycle.

7. method of rate control as claimed in claim 6 wherein, changes between described transmission rate two or more admissible rates in the different frame of same rate controlled in the cycle, to obtain the effective speed in described rate controlled cycle.

8. method of rate control as claimed in claim 1, wherein, the required speed of the desired service quality of described each Service Instance of maintenance is shaken based on expectation.

9. method of rate control as claimed in claim 1, wherein, the required speed of the desired service quality of described each Service Instance of maintenance is based on the expectation throughput.

10. method of rate control as claimed in claim 1, wherein, the required speed of the desired service quality of described each Service Instance of maintenance is based on expected delay.

11. method of rate control as claimed in claim 1, wherein, the required speed of the desired service quality of described each Service Instance of maintenance is based on the expectation frame error rate.

12. method of rate control as claimed in claim 1, wherein, described transmission rate is the expectation transmission rate of being calculated by travelling carriage, and comprises the step that sends the data rate request that comprises described expectation transmission rate from described travelling carriage to the base station.

13. a travelling carriage comprises:

Transceiver is used for transmitting and received signal; And

Controller, in operation, be connected to described transceiver, described controller comprises according to the desired service quality of a plurality of Service Instances determines the total data transmission rate on the reverse chain channel and sends the rate calculator of data rate request from described travelling carriage to the base station that described data rate request indicates the expectation transmission rate based on described aggregate rate.

14. travelling carriage as claimed in claim 13, wherein, described rate controlled processor is selected the expectation transmitted data rates according to the required aggregate rate of described desired service quality that keeps all Service Instances from the admissible rate calendar.

15. travelling carriage as claimed in claim 14, wherein, described rate controlled processor selection is more than or equal in the admissible rate of the required aggregate rate of the described desired service quality that keeps all Service Instances immediate one.

16. travelling carriage as claimed in claim 14, wherein, described rate controlled processor selection is less than or equal in the admissible rate of the required aggregate rate of the described desired service quality that keeps all Service Instances immediate one.

17. travelling carriage as claimed in claim 13, wherein, described rate controlled processor is determined the effective speed in predetermined control cycle according to described aggregate rate.

18. travelling carriage as claimed in claim 17, wherein, the described rate controlled cycle comprises a plurality of frames, and the transmission rate of each frame is selected to obtain the effective speed of described control cycle.

19. travelling carriage as claimed in claim 13, wherein, described rate calculator determines to keep the required estimation rate of desired service quality of each Service Instance according to the expectation shake.

20. travelling carriage as claimed in claim 13, wherein, described rate calculator determines to keep the required estimation rate of desired service quality of each Service Instance according to the expectation throughput.

21. travelling carriage as claimed in claim 13, wherein, described rate calculator determines to keep the required estimation rate of desired service quality of each Service Instance according to expected delay.

22. travelling carriage as claimed in claim 13, wherein, described rate calculator determines to keep the required estimation rate of desired service quality of each Service Instance according to the expectation frame error rate.

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