CN1762169A - Outer-loop power control for wireless communication systems - Google Patents

Abstract

Techniques for efficient signaling to and from a plurality of mobile stations are disclosed. In one embodiment, a subset of mobile stations may be allocated a portion (350) of the shared resource with one or more individual access grants (370), another subset may be allocated a portion of the shared resource with a single common grant (370), and yet another subset may be allowed to use a portion of the shared resource without any grant. In another embodiment, an acknowledge and continue command is used to extend all or a subset of the previous grants without the need for additional requests and grants, and their associated overhead. In one embodiment, a traffic to pilot ratio (T/P) is used to allocate a portion of the shared resource, allowing a mobile station flexibility in selecting its transmission format based on T/P.

Description

Outer Loop Power Control for Wireless Communication Systems

This patent application claims Provisional Application 60/448,269, filed February 18, 2003, entitled "Reverse Link Data Communications," and the application filed March 6, 2003, entitled "Reverse Link Communications for Method and Apparatus for "Provisional Application 60/452,790" and Provisional Application 60/470,770, filed May 14, 2003, entitled "Outer Loop Power Control for Rel. are hereby expressly incorporated by reference.

Background technique

technical field

The present invention generally relates to the field of radio communication, and more particularly, the present invention relates to a mechanism for providing outer loop power control in a multi-channel wireless communication system with varying channel quality.

Related areas

Wireless communication technology is rapidly developing, and wireless communication systems are being used to provide an increasing share of the communication capacity currently available to users. This is the case despite the additional technical hurdles faced in implementing wireless communication systems compared to wired systems. For example, in order to maximize system performance, wireless communication systems must deal with issues related to power control between the base station and its mobile stations, while wired systems do not.

One type of wireless communication system includes a cellular CDMA (Code Division Multiple Access) system configured to support voice and data communications. This system may have multiple base stations communicating with multiple mobile stations over wireless channels. (The base stations are also typically connected by wired networks to various other systems, such as the public switched telephone network.) Each base station communicates with a group of mobile stations within the sector corresponding to that base station. The base station is responsible for controlling power in communications between the base station and mobile stations to minimize interference and maximize throughput, and to enable mobile stations to conserve energy extending the amount of time they can be used.

Typically, power control between the base station and the mobile station in this type of system is based on the error rate associated with the communication between the base station and the mobile station. Ideally, the power level transmitted from the mobile station to the base station is set to a level that results in a predetermined frame error rate. For example, each time a frame of data is successfully received by the base station from the mobile station, the base station may instruct the mobile station to reduce its power by a certain amount. In other words, the mobile station reduces its power level. If, on the other hand, a received frame of data contains errors, the base station may instruct the mobile station to increase its power by a certain amount (that is, to increase its power level). In this way, the power level of the mobile station is adjusted to a power level that maintains a predetermined acceptable error rate.

However, this method for power control is based on a single channel and cannot account for the varying transfer characteristics of multiple reverse link channels. In a system with multiple channels, the power levels of the different channels may be mutually constrained so that optimizing the power level based on the error rate associated with one channel provides acceptable performance on that particular channel, but at the same time may Unsatisfactory performance levels are provided in other channels. Although the adjustment of the power variation may take into account the performance of multiple channels, there will almost certainly be some channels for which the power level is too low and some channels for which the power level is too high.

Contents of the invention

Some wireless communication systems have multiple channels that can transmit simultaneously. Rather than performing power control based on aggregate metrics and having better than necessary performance on some channels and unsatisfactory performance on others, it is desirable to provide a satisfactory level of service on each channel.

Various embodiments of the present invention attempt to improve power control in systems with multiple channels by providing some independently controlled levels for different channels. More specifically, the power levels of one or more traffic channels and a pilot channel are controlled to increase or decrease in unison so that the ratio of traffic to pilot signals is maintained at approximately the same value for each of these channels. Other channels are controlled by setting corresponding variable service-to-pilot ratios. Then, the power level of the corresponding channel is adjusted based on the received traffic-to-pilot ratio and the set pilot power level.

One embodiment includes a method for controlling power in a wireless communication system having multiple reverse link communication channels. The method includes adjusting power levels of the first set of channels and corresponding pilot channels and adjusting traffic-to-pilot (T/P) ratios for one or more remaining channels independently of the pilot channel power levels. In one embodiment, the first set of channels actually includes a single channel (the "first" channel). The power levels of the first channel and the pilot channel are adjusted in such a way that a set T/P ratio is maintained for these channels. In this embodiment, the first channel and the pilot channel are adjusted by determining whether frames received on the first channel contain errors and increasing or decreasing the power level if those frames contain or do not contain errors, respectively. In one embodiment, the power level is actually increased or decreased by sending messages from the base station to the mobile station indicating that the mobile station should increase or decrease the power level of these channels. When the mobile station receives these messages, it takes appropriate action. In this embodiment, the T/P ratio of the additional channel is adjusted in a similar manner (ie, by determining whether a frame received on the additional channel contains an error and increasing or decreasing the T/P ratio appropriately). The T/P ratio, if increased or decreased, is then communicated to the mobile station, which controls the transmission parameters for each channel based on the received T/P ratio.

An alternative embodiment of the present invention includes a wireless communication system having a base station and a mobile station connected to the base station by a wireless communication link, wherein the base station receives from the mobile station on a plurality of reverse link channels of the wireless communication link data, and wherein the base station adjusts power levels for a first set of reverse link channels and a pilot channel, and adjusts a traffic-to-pilot (T/P) ratio for each of the one or more additional reverse link channels. In one embodiment, the first set of channels includes only a single channel (the "first" channel) and when adjusting the power levels of these channels, the base station maintains a set of T/P ratios for the first and pilot channels. In one embodiment, the base station determines whether data received on the first channel contains errors, increases the power levels of the first and pilot channels if the data received on the first channel contains errors, and increases the power levels of the first and pilot channels if the data does not contain errors Reduce the power level of these channels. In one embodiment, the base station increases or decreases the power level by sending a message from the base station to the mobile station indicating that the mobile station should increase or decrease the power level as appropriate. The mobile station receives this information and takes appropriate action. In one embodiment, the T/P ratio of the additional channel is similarly adjusted by determining whether an error is contained in the frame received on the additional channel and appropriately increasing or decreasing the corresponding T/P ratio maintained at the base station. Then, the T/P ratio as increased or decreased is transmitted to the mobile station, which controls the transmission parameters for each channel based on the received T/P ratio.

Many additional implementations are also possible.

Description of drawings

Various aspects and features of the invention are disclosed by the ensuing detailed description and references to the accompanying drawings, in which:

FIG. 1 is a diagram illustrating the structure of a typical wireless communication system according to one embodiment;

Figure 2 is a functional block diagram illustrating the basic structural components of a wireless transceiver system, according to one embodiment;

Figure 3 is a diagram illustrating multiple channels between a mobile station and a base station, according to one embodiment;

Figure 4 is a flowchart illustrating a method used in connection with a first channel, where the power levels of both the first channel (traffic channel) and the pilot channel are adjusted according to one embodiment;

Figure 5 is a flowchart illustrating a method used in conjunction with a second channel, wherein instead of adjusting the power level of both the second (traffic) channel and the pilot channel, the T/P of the second channel is adjusted according to one embodiment Compare.

Figure 6 is a schematic diagram illustrating the relative power levels of the first channel and the pilot channel and their adjustment according to Figure 4; and

FIG. 7 is a schematic diagram illustrating the relative power levels of the second channel and the pilot channel and their adjustment according to FIG. 5 .

While the invention is capable of various modifications and alternative forms, specific embodiments thereof are shown as examples in the drawings and detailed description. It should be understood, however, that the drawings and detailed description do not limit the invention to the particular embodiments described.

Detailed ways

One or more implementations of the invention are described below. It should be noted that these and any other embodiments described below are exemplary and intended to illustrate the invention rather than limit it.

As described herein, various embodiments of the invention include systems and methods for providing power control for multiple channels, wherein considerable independence is provided in the control of each channel.

In one embodiment, a wireless communication system provides multiple reverse link channels for data communication from mobile stations to base stations. For the first of these channels, the base station controls the power level of that channel to maintain a substantially constant traffic-to-pilot (T/P) ratio. In other words, the power levels of traffic and pilot signals are increased or decreased proportionally. For example, if an error is received on the channel, the power level of traffic and pilot is increased, and if no error is received, the power level of traffic and pilot is decreased. For the remaining channels, power control is performed by increasing or decreasing the T/P ratio instead of increasing or decreasing the power level of both traffic and pilot. Therefore, if an error is received on one of these channels, the corresponding T/P ratio is increased while the pilot power level is maintained. On the other hand, if no errors are received on this channel, the T/P ratio is reduced while the pilot power level remains unchanged.

In an optional embodiment, the wireless communication system also provides a plurality of reverse link channels for data communication from the mobile station to the base station. However, in this embodiment, the power level of the pilot is adjusted in coordination with multiple traffic channels rather than with a single channel. In this embodiment, the T/P ratios of the plurality of channels in the first group are substantially fixed, and the power levels of the pilot and traffic channels of the first group are adjusted up or down simultaneously. In one embodiment, the T/P ratio may be initially adjusted before being fixed. The power levels of these channels are adjusted based on a composite function of errors detected in the data received by all channels in the first group. For example, the function may include a maximum up-step, plus a maximum down-step (where the down-step is considered to have a negative value), where the maximum up-step and maximum down-step are used as for a single channel Calculated in the same way. For the remaining channels, the T/P ratios of these channels are adjusted in the same manner as described above. In other words, if an error is received on one of these channels, the corresponding T/P ratio increases, but if no error is received on this channel, the T/P ratio decreases.

A preferred embodiment of the present invention is implemented in a wireless communication system generally conforming to a version of the cdma2000 specification. cdma2000 is a third generation (3G) wireless communication standard based on the IS-95 standard. The cdma2000 standard has evolved and continues to evolve to support new services in the standard 1.25MHz carrier. The preferred embodiment of the present invention is intended to work in systems utilizing version D of the cdma2000 standard, but other embodiments may be implemented in other versions of cdma2000 or in systems conforming to other standards (eg, W-CDMA). Accordingly, the embodiments described herein should be considered as illustrative rather than restrictive.

Referring to FIG. 1, a diagram illustrating the structure of an exemplary wireless communication system is shown. As shown in the figure, system 100 includes a base station 110 configured to communicate with a plurality of mobile stations 120 . For example, a mobile station 120 configured for wireless communication may be a cellular telephone, a personal information manager (PIM or PDA), or the like. It should be noted that these devices need not actually be "mobile", but may simply communicate with base station 110 via a wireless link. Base station 110 transmits data to mobile station 120 via a corresponding forward link (FL) channel, and mobile station 120 transmits data to base station 110 via a corresponding reverse link (RL) channel.

It should be noted that for purposes of this disclosure, like items in the figures may be shown by like reference numbers followed by lower case letters, eg, 120a, 120b, and so on. These items may here be referred to in their entirety only by reference numerals.

Base station 110 is also connected to switching station 130 by a wired link. A link to switching station 130 allows base station 110 to communicate with various other system components, such as data server 140 , public switched telephone network 150 , or the Internet 160 . It should be noted that the mobile stations and system components in this figure are exemplary and that other systems may include other types and other combinations of devices.

In practice, however, the specific design of base station 110 and mobile station 120 may vary considerably, each acting as a wireless transceiver for communicating over the forward and reverse links. Therefore, base station 110 and mobile station 120 have the same general structure. This structure is illustrated in Figure 2.

Referring to FIG. 2 , there is shown a functional block diagram illustrating the basic structural components of a wireless transceiver system, according to one embodiment. As shown in the figure, the system includes a transmit subsystem 222 and a receive subsystem 224 , each of which is connected to an antenna 226 . Transmit subsystem 222 and receive subsystem 224 may collectively be referred to as a transceiver subsystem. Transmit subsystem 222 and receive subsystem 224 access the forward and reverse links through antenna 226 . Transmit subsystem 222 and receive subsystem 224 are also connected to processor 228 configured to control transmit and receive subsystems 222 and 224 . Memory 230 is coupled to processor 228 to provide a working area and local memory for the processor. A data source 232 is coupled to processor 228 to provide data for system delivery. For example, data source 232 may include a microphone or input from a network device. The data is processed by processor 228 and then sent to transmit subsystem 222 which communicates the data via antenna 226 . Data received by receive subsystem 224 via antenna 226 is forwarded to processor 228 for processing and then to data output 234 for presentation to a user. Data output 234 may include devices such as speakers, visual displays, or output to network devices.

Those skilled in the art to which the present invention pertains will appreciate that the structure depicted in FIG. 2 is illustrative and that other embodiments may use alternative configurations. For example, processor 350, which may be a general purpose microprocessor, digital signal processor (DSP), or special purpose processor, may perform some or all of the functions of other portions of the transceiver, or any other processing required by the transceiver. Therefore, the scope of the claims appended hereto should not be limited to the specific arrangements described herein.

Considering the structure of Figure 2 implemented in a mobile station, the components of the system can be viewed as a transceiver subsystem connected to a processing subsystem, where the transceiver subsystem is responsible for receiving and transmitting data over a wireless channel and the processing subsystem is responsible for preparing and providing The Data to Transceiver Subsystem is used to transmit as well as receive and process data from the Transceiver Subsystem. The transceiver subsystem may be considered to include transmit subsystem 222 , receive subsystem 224 and antenna 226 . A processing subsystem may be considered to include processor 228 , memory 230 , data source 232 and data output 234 .

As indicated above, the communication link between the base station and the mobile station actually consists of different channels. Referring to FIG. 3, a diagram illustrating a number of channels between a mobile station and a base station is shown. As shown, base station 110 transmits data to mobile station 120 over a set of forward link channels 310 . Typically, these channels include traffic channels and control channels, through which data is transmitted, and control signals are transmitted through control channels. Each traffic channel typically has one or more control channels associated with it. For example, forward link channels 310 may include a forward fundamental channel (F-FCH) that may be used to transmit low-speed data, a forward supplemental channel (F-SCH) that may be used for high-speed, point-to-point communications, or a forward supplemental channel (F-SCH) that may be used Forward High Speed Broadcast Channel (F-HSBCH) for broadcasting messages to multiple receivers. These channels may also include the Forward Dedicated Control Channel (F-DCCH), the Forward Broadcast Control Channel (F-BCCH), or the Forward Paging channel (F-PCH).

Mobile station 120 transmits data to base station 110 via set of reverse link channels 320 . Additionally, these channels typically include traffic channels and control channels. The mobile station 120 may transmit data back to the base station over channels such as Reverse Access Channel (R-ACH), Reverse Extended Access Channel (R-EACH), Reverse Request Channel (R-REQCH), Reverse Enhanced Supplementary Channel (R-ESCH), Reverse Dedicated Control Channel (R-DCCH), Reverse Common Control Channel (R-CCCH) or Reverse Rate Indicator Channel (R-RICH).

In many cases, reverse link capacity is limited by interference. The base station allocates available reverse link communication resources to mobile stations for efficient use to maximize throughput according to quality of service (QoS) requirements for the various mobile stations.

Maximizing the utilization of reverse link communication resources involves several factors. One factor to consider is the mix of scheduled reverse link transmissions from different mobile stations, each of which may experience varying channel quality at any given moment. To increase the overall throughput (the total amount of data transmitted by all mobile stations in a cell), it is desirable that the entire reverse link be fully utilized whenever there is reverse link data transmitted. In order to fill up the available capacity, some mobile stations may be allowed access at the highest rate they can support. Additional mobile stations may be allowed access until capacity is reached. When deciding which mobile stations to schedule, the base station can thus take into account the maximum rate each mobile station can support and the amount of data each mobile station must transmit. A mobile station capable of supporting greater throughput (taking into account the data rate the mobile station can support and the amount of data the mobile station must transmit) can be selected in place of an alternative mobile station currently unable to support higher throughput.

Another factor to consider is the quality of service requested by each mobile station. Delays in accessing a particular mobile station may be allowed in the hope that the mobile station's channel (or more specifically, its supportable throughput) will improve, and a mobile station capable of supporting higher throughput may be selected. However, situations may arise where a sub-optimal mobile station may need to be granted access to allow the mobile station to meet a guaranteed minimum quality of service. Thus, the actual scheduled data throughput may not be the absolute maximum, but may be optimized based on channel conditions, available mobile station transmit power, quality of service requirements, and similar factors.

Various scheduling mechanisms can be used to allow mobile stations to transmit data on the reverse link. One type of reverse link transmission involves a mobile station making a request to transmit on the reverse link. The base station determines whether the available resources can accommodate the request and grants permission through the base station to allow the transmission. This permission is made explicitly for a single mobile station, or it can be a common permission for all mobile stations. Alternatively, the mobile station may not have sufficient data or channel quality to determine a request, and may transmit data to the base station spontaneously.

The base station allocates reverse link capacity to one or more mobile stations. A mobile station that is granted access is allowed to use the maximum power level at which it can transmit with the permission. In one embodiment, reverse link capacity is allocated using traffic-to-pilot (T/P) ratios. Since each mobile station's pilot signal is adaptively controlled through power control, the specified T/P ratio represents the available power for transmitting data on the reverse link. As shown above, the base station may grant special permission to one or more mobile stations, indicating the T/P value assigned to each mobile station, and may also issue public permission to the remaining mobile stations that have requested access, indicating that they are allowed to use The maximum T/P value transmitted by those remaining mobile stations.

Traditionally, T/P has been used to allocate reverse link capacity to different mobile stations without regard to the specific channel used by each mobile station. In other words, actually, power control is performed on a per mobile station basis. In the present system, the T/P ratio for each channel between a specific mobile station and a base station is included in the power control method, not just for allocation between mobile stations.

Referring to Figures 4 and 5, there are shown flow diagrams illustrating the method employed by one embodiment to control power to various channels between a mobile station and a base station. Figure 4 describes a method used in connection with the first channel, where the power levels of both the first channel (traffic channel) and the pilot channel are adjusted. The power levels of the first and pilot channels are simultaneously increased or decreased to maintain the T/P ratio between them. Figure 5 describes a method used in conjunction with a second channel, where instead of adjusting the power levels of the second (traffic) and pilot channels, the T/P ratio of the second channel is adjusted. Thus, the power level of the second channel is effectively adjusted without affecting the power level of the pilot channel.

In one embodiment, the first channel is the reverse link fundamental channel (R-FCH), and the power level for this channel is adjusted in coordination with the pilot channel. This channel carries voice communications, which are typically of primary importance in wireless communication systems (eg, cellular telephone systems). Since the level of service on this channel may be critical, using it as the basis for power control ensures that the level of service will be satisfactory, although it may not be possible to provide a satisfactory level of service on all channels.

Referring again to FIG. 4, power control for the first channel is performed by first receiving a frame of data at the base station (block 410) and determining whether the frame contains errors (block 420). If the frame contains errors (block 430), the power level of the first channel is too low, so the base station sends an UP message to the mobile station (block 440) to indicate that the power level of this channel and the pilot channel should be lowered. Increase. When this information is received by the mobile station, the mobile station increases the power levels of the first channel and the pilot channel (block 450). If the frame contains no errors (block 430), the power level of the first channel is sufficiently high and the base station sends a DOWN message to the mobile station (block 460) to indicate the power level of this channel and the pilot channel should be reduced. When this information is received by the mobile station, the mobile station reduces the power levels of the first channel and the pilot channel (block 470).

When an error is received on one of the channels and it is necessary to send an UP or DOWN message to the mobile station, the amount by which the power level (or T/P ratio) is increased (up order) or decreased (down order) can vary with implementation And change. Typically, the amount by which the power level is increased is actually greater than the amount by which the power level is decreased. In a typical implementation, the pilot is combined with a single traffic channel for power control, the upper order has a value of ×dB, and the lower order has a value of ×/(1/FER-1), where FER is the frame error of the pilot channel Rate. Similarly, the T/P ratio of each additional channel may be increased by an amount Y and decreased by an amount Y/(1/FER-1), where the value of FER corresponds to the channel whose T/P ratio was increased/decreased.

In embodiments where pilots are power controlled in conjunction with multiple traffic channels, the calculation of the upper and lower order may be somewhat more complex, although this is not necessarily the case. In a typical embodiment, the upper order is selected as the maximum value among the calculated upper orders for multiple channels. In this embodiment, the lower order is selected as the minimum of the calculated lower orders for multiple channels. In an alternative embodiment, the upper order may be selected as the minimum of the calculated upper orders for multiple channels, and the lower order is selected as the maximum of the calculated lower orders for the multiple channels value. In yet another embodiment, the upper order is selected as the maximum of the calculated upper orders for the plurality of channels, and the lower order is calculated as the sum of the calculated lower orders for the plurality of channels. In one embodiment, the final pilot adjustment is calculated as the sum of the upper and lower orders. In another embodiment, the final pilot adjustment is further quantized to a limited level and signaled to the mobile station. In yet another embodiment, the quantization has two levels, with a fixed amount up or down.

Referring again to FIG. 5, power control for the second channel is performed by receiving another frame of data at the base station (block 510) and determining whether the received frame contains errors (block 520). If the frame contains errors (block 530), the T/P ratio is incremented (block 540) by the base station, which maintains the current T/P value for each mobile station communicating with it. A message is then sent from the base station to the mobile station indicating the new T/P value (block 560). The mobile station then sets the power level of the second channel according to the new T/P. Unlike the flow diagram of Figure 4, the pilot power level is not affected by errors experienced on the second channel or caused by changes in T/P. If the frame contains no errors (block 530), the T/P ratio is reduced (block 550), and a corresponding message is sent to the mobile station (block 560). Furthermore, the new T/P does not affect the power level of the pilot signal.

The effect of the method described in FIG. 4 is illustrated in FIG. 6 . FIG. 6 is a diagram illustrating relative power levels of a first channel and a pilot channel. The graph of Figure 6 shows the power levels of these channels as a function of time. The power level of the first channel is indicated by reference numeral 610 and the power level of the pilot channel is indicated by reference numeral 620 . It can be seen that the power level of curve 610 is proportional to the power level of curve 620 . The ratio (T/P) of the curve is kept constant. When the power level of the curve is reduced at instant t1, the scale of the curve remains constant. In other words, before and after time t1, the T/P ratio is the same (that is, T/P is equal to T'/P').

The effect of the method described in FIG. 5 is illustrated in FIG. 7 . The figure is a diagram illustrating the relative power levels of the second channel and the pilot channel. The curve 710 corresponding to the power level of the second channel is proportional to the curve 720 corresponding to the power level of the pilot channel, but when it is necessary to reduce the power level of the second channel (for example, at time t2), the pilot power level is not affected. Therefore, although the curve is proportional before and after time t2, the proportion of the curve changes (that is, T/P is not equal to T'/P').

By implementing power control on separate channels as described above, the power levels and/or T/P ratios of these channels can be optimized with some independence from each other. In one embodiment, one of the channels can be optimized by adjusting the channel and pilot channel power levels simultaneously, while the remaining channels can be optimized by adjusting their respective T/P ratios. In another embodiment, one set of channels incorporates pilots for simultaneous power control, while another set adjusts its T/P ratio without affecting the pilots or the power level of the first set of channels.

The mobile station can then determine whether to transmit data on each channel, and select the appropriate transmit power, data rate, and other parameters for these transmissions. The mobile station's choice of transmission parameters may involve different considerations. For example, as described above, a mobile station may trade off throughput for latency in deciding whether to use autonomous transfer to transfer data. In other words, the mobile station can transmit immediately to reduce latency, or can request a higher rate of transmission and wait for a common or special permit. Furthermore, given the maximum T/P that the mobile station is allowed to transmit, the mobile station can select a data rate (not to exceed the allowed T/P) to suit the latency and/or throughput requirements for the data being transmitted.

Different mobile stations communicating with a base station can support different throughput levels. This situation may be due to the mobile station being at different locations within the cell, moving at different speeds, and experiencing varying channel conditions. The throughput that can be supported by a mobile station can also be affected by the mobile station's selection of various transmission characteristics, such as transmission power, transmission rate and modulation format. A mobile station's selection of these characteristics may be based on a number of factors. For example, the transfer rate can be increased (by reducing the coding rate, increasing the symbol rate, or using a higher order modulation scheme) to increase data throughput.

Another factor is the power of the mobile station. Mobile stations have a finite amount of transmit power available. Since the data transfer rate is directly related to the transfer power, the transfer rate of the mobile station can be limited by the maximum power of the mobile station amplifier. The available amount of mobile station transmit power can then be allocated to one or more pilot channels, one or more data channels and any other associated control channels. To be effective, the associated pilot channel must be reliably received to provide a phase reference for modulation. Therefore, a portion of the available transmit power is allocated to the pilot, and increasing that portion will increase the reliability of pilot reception. However, increasing the portion of available transmit power allocated to pilot also reduces the amount of power available for data transmission, and reducing the portion of available transmit power allocated to data also reduces modulation reliability. However, for any given T/P ratio, an appropriate modulation format and transfer rate can be determined.

Mobile station transmit power can also be managed by the base station to avoid excessive interference with other mobile stations by using power control and various data transmission scheduling techniques. Power control is used to maintain the reverse link signal at a level suitable for the base station. The base station receives pilot signals from each mobile station and controls the power level of the mobile stations so that the pilot power received from each mobile station is approximately equal. Since the pilot level is approximately the same for each mobile station, the T/P ratio for the mobile station becomes an indicator of the communication capacity used by the mobile station during reverse link transmissions. After the base station determines the T/P ratio for each mobile station, the mobile station can then appropriately select transmit power, transmit rate and modulation format to stay within the allowed T/P ratio.

Various aspects and features of the invention have been described above with respect to specific embodiments. As used herein, the terms "comprises", "comprises" or any other variation should be interpreted as including non-exclusively the elements or limitations that follow those terms. Accordingly, a system, method, or other implementation comprising a set of elements is not limited to those elements, and may include other elements that are not expressly listed or claimed to be inherent to the implementation.

The invention has been described with reference to specific embodiments, it being understood that these embodiments are illustrative and that the scope of the invention is not limited to these embodiments. Many variations, modifications, additions and improvements to the above-described embodiments are possible. These changes, modifications, additions and improvements fall within the scope of the invention as detailed in the following claims.

Claims (41)

1. method that is used in wireless communication system power controlling with a plurality of reverse link communications channels, described method comprises:

Regulate the power level of first group of channel and corresponding pilot channel; With

Irrespectively regulate service pilot (T/P) ratio that is used for one or more residue channels with the power level of described pilot channel.

2. the method for claim 1 further comprises when regulating the power level of described first group of channel and described pilot channel, keeps the ratio of the power level of described first group of channel and described pilot channel.

3. the method for claim 1, wherein said first group of channel comprises individual channel, the power level of wherein regulating described first group of channel and described corresponding pilot channel comprises determines whether the data that receive comprise mistake on described individual channel, and, if the data that receive at described individual channel comprise mistake, increase the power level of described individual channel and described corresponding pilot channel, if the data that receive at described individual channel do not comprise mistake, reduce the power level of described individual channel and described corresponding pilot channel.

4. method as claimed in claim 3, determine wherein whether the data that receive on described individual channel comprise mistake and carried out by the base station, wherein said method comprises that further described base station sends a message to travelling carriage to increase or to reduce the power level of described individual channel and described corresponding pilot channel.

5. method as claimed in claim 4, the power level that wherein increases described individual channel and described corresponding pilot channel responds described message by travelling carriage and carries out.

6. method as claimed in claim 3, wherein said individual channel comprises voice channel.

7. the method for claim 1, wherein said first group of channel comprises a plurality of channels, and the power level of wherein regulating described first group of channel and described corresponding pilot channel is included as each channel in described first group and determines whether comprise mistake and determine the comprehensive adjustment of the power level of described first group of channel and described corresponding pilot channel based on the mistake that receives at described a plurality of channels in the data that described individual channel receives.

8. method as claimed in claim 7, determine that wherein the comprehensive adjustment of the power level of described first group of channel and described corresponding pilot channel comprises:

Be each channel in described first group,

Determine whether the data that receive comprise mistake on described channel,

If the data that receive on described channel comprise mistake, determine corresponding increase power level adjustment and

If the data that receive at described individual channel do not comprise mistake, determine the corresponding power level adjustment that reduces; With

Calculate the function that described comprehensive adjustment conduct is used for the increase of described first group channel and reduces power level adjustment.

9. method as claimed in claim 8, the function that wherein is used for the increase of described first group channel and reduces power level adjustment comprise increases power level adjustment with maximum and all reduce the power level adjustment addition.

10. method as claimed in claim 8, the function that wherein is used for the increase of described first group channel and reduces power level adjustment comprise that the increase power level adjustment with maximum is added to the minimum power level adjustment that reduces.

11. method as claimed in claim 8, the function that wherein is used for the increase of described first group channel and reduces power level adjustment comprise that the increase power level adjustment with minimum is added to the maximum power level adjustment that reduces.

12. method as claimed in claim 8, wherein said increase and the function that reduces power level adjustment are limited to a limited number of quantization level.

13. the method for claim 1, wherein be that the described T/P of each described one or more residue channel adjustment is than comprising whether the data of determining in that described channel receives comprise mistake, if the data that receive at described channel comprise mistake, increase the T/P ratio that is used for described channel, and, if the data that receive at described channel do not comprise mistake, reduce to be used for the T/P ratio of described channel.

14. method as claimed in claim 13, the T/P that wherein determines whether to comprise mistake and increase or reduce to be used for described channel in the data that described channel receives is than being carried out by the base station, and wherein said method comprises that further described base station sends a message to the T/P ratio that travelling carriage represents to be used for described channel.

15. method as claimed in claim 14 comprises that further described travelling carriage receives described message and selects transmission characteristic according to the T/P ratio that is used for described channel for described channel.

16. a system that is used in the wireless communication system power controlling with a plurality of reverse link communications channels comprises:

The base station; With

Be connected to the travelling carriage of described base station by wireless communication link;

Wherein said base station is configured on a plurality of reverse chain channels of described wireless communication link and receives data from described travelling carriage; With

Wherein said base station is configured to be regulated the power level be used for first group of reverse chain channel and is used for the power level of pilot channel, and be that each of one or more additional reverse chain channels regulated service pilot (T/P) and compared.

17. system as claimed in claim 16, wherein said base station is configured to the described power level be used for described first group of reverse chain channel and the described pilot channel ratio with the power level of the power level that is kept for described first group of reverse chain channel and described pilot channel of regulating.

18. system as claimed in claim 16, wherein said first group of channel comprises that individual channel and wherein said base station are configured to the data of determining in that described single reverse chain channel receives and whether comprise mistake, and, if the data that receive at described single reverse chain channel comprise mistake, the power level of described single reverse chain channel and described pilot channel is increased, and, if the data that receive at described single reverse chain channel do not comprise mistake, the power level of described single reverse chain channel and described pilot channel is reduced.

19. system as claimed in claim 18, wherein said base station is configured to by sending corresponding message and makes the power level increase of described single reverse chain channel and described pilot channel or reduce to described travelling carriage.

20. system as claimed in claim 19, wherein said travelling carriage is configured to the power level that increases or reduce described single reverse chain channel and described pilot channel according to described message.

21. system as claimed in claim 16, wherein said first group of channel comprises a plurality of channels, and wherein said system is configured to by determine whether comprise mistake and determine that based on the mistake that receives the comprehensive adjustment of the power level of described first group of channel and described corresponding pilot channel regulates the power level of described first group of channel and described corresponding pilot channel on described a plurality of channels in the data that receive on the described individual channel for each channel in described first group.

22. method as claimed in claim 21, wherein said system are configured to the comprehensive adjustment of the power level of determining described first group of channel and described corresponding pilot channel, it is regulated by following steps:

Be each channel in described first group,

Determine whether the data that receive comprise mistake on described channel,

If the data that receive on described channel comprise mistake, determine corresponding increase power level adjustment and

If the data that receive at described individual channel do not comprise mistake, determine the corresponding power level adjustment that reduces; With

Calculate the function that described comprehensive adjustment conduct is used for the increase of described first group channel and reduces power level adjustment.

23. the system as claimed in claim 22 wherein is used for the increase of described first group channel and the function of the power level adjustment that reduces comprises and maximum increased power level adjustment and all reduce the power level adjustment addition.

24. the system as claimed in claim 22 wherein is used for the increase of described first group channel and the function of the power level adjustment that reduces comprises that the increase power level adjustment with maximum is added to the minimum power level adjustment that reduces.

25. the system as claimed in claim 22 wherein is used for the increase of described first group channel and the function of the power level adjustment that reduces comprises that the increase power level adjustment with minimum is added to the maximum power level adjustment that reduces.

26. the system as claimed in claim 22, wherein said increase and the function that reduces power level adjustment are limited to a limited number of quantization level.

27. system as claimed in claim 16, wherein said base station is configured to the data of determining in that each additional reverse link channel receives and whether comprises mistake, and, if the data that receive at described additional reverse link channel comprise mistake, increase the T/P ratio of described additional reverse link channel, if the data that receive at described additional reverse link channel do not comprise mistake, reduce the T/P ratio of described additional reverse link channel.

28. system as claimed in claim 27, wherein said base station is configured to the message of the T/P that the is increased or decreased ratio that sends the described additional reverse link channel of expression to described travelling carriage.

29. system as claimed in claim 28, wherein said travelling carriage is configured to the power level that described additional reverse link channel is set according to described message.

30. the base station that can operate by radio communication channel and mobile communications, wherein said base station comprises:

Processing subsystem; With

Be connected to the transceiver subsystem of described processing subsystem;

Wherein said transceiver subsystem is configured to received signal on first group of reverse chain channel, pilot channel and one or more additional reverse link channel; With

Wherein said base station is configured to regulates the power level be used for described first group of reverse chain channel and the power level that is used for described pilot channel, and regulates each service pilot (T/P) ratio that is used for one or more additional reverse link channels.

31. base station as claimed in claim 30, wherein said first group of reverse chain channel comprises single reverse chain channel, and wherein said base station is configured to the power level be used for described single reverse chain channel and the described pilot channel ratio with the power level of the power level that is kept for described single reverse chain channel and described pilot channel of regulating.

32. base station as claimed in claim 30, wherein said base station is configured to the data of determining in that described single reverse chain channel receives and whether comprises mistake, if the data that receive at described single reverse chain channel comprise mistake, the power level of described single reverse chain channel and described pilot channel is increased, if the data that receive at described single reverse chain channel do not comprise mistake, the power level of described single reverse chain channel and described pilot channel is reduced.

33. base station as claimed in claim 30, wherein said base station is configured to by sending corresponding message and the power level of described single reverse chain channel and described pilot channel is increased or reduces to travelling carriage, and described travelling carriage is configured to the power level that increases or reduce described single reverse chain channel and described pilot channel according to described message.

34. base station as claimed in claim 30, wherein said first group of channel comprises a plurality of channels, and wherein said base station is configured to by determine whether comprise mistake and determine that based on the mistake that receives at described a plurality of channels the comprehensive adjustment of the power level of described first group of channel and described corresponding pilot channel regulates the power level of described first group of channel and described corresponding pilot channel in the data that described individual channel receives for each channel in described first group.

35. base station as claimed in claim 34, wherein said base station are configured to the comprehensive adjustment of the power level of determining described first group of channel and described corresponding pilot channel, it is regulated by following steps:

Be each channel in described first group,

Determine whether comprise mistake in the data that described channel receives,

If the data that receive at described channel comprise mistake, determine corresponding increase power level adjustment and

If the data that receive at described individual channel do not comprise mistake, determine the corresponding power level adjustment that reduces; With

Calculate the function that described comprehensive adjustment conduct is used for the increase of described first group channel and reduces power level adjustment.

36. base station as claimed in claim 35, the function that wherein is used for the increase of described first group channel and reduces power level adjustment comprise the power level adjustment addition that increase power level adjustment and all with maximum reduce.

37. base station as claimed in claim 35, the function that wherein is used for the increase of described first group channel and reduces power level adjustment comprise that the increase power level adjustment with maximum is added to the minimum power level adjustment that reduces.

38. base station as claimed in claim 35, the function that wherein is used for the increase of described first group channel and reduces power level adjustment comprise that the increase power level adjustment with minimum is added to the maximum power level adjustment that reduces.

39. base station as claimed in claim 35, the function of wherein said increase and the power level adjustment that reduces is limited to a limited number of quantization level.

40. base station as claimed in claim 30, wherein said base station is configured to the data of determining in that each additional reverse link channel receives and whether comprises mistake, if the data that receive at described additional reverse link channel comprise mistake, increase the T/P ratio of described additional reverse link channel, if the data that receive at described additional reverse chain channel do not comprise mistake, reduce the T/P ratio of described additional reverse chain channel.

41. base station as claimed in claim 30, the T/P that wherein said base station is configured to the described additional reverse link channel of expression is sent to travelling carriage than the message that increases or reduce, and this travelling carriage is configured to the power level that described additional reverse link channel is set according to described message.

Images