MXPA00002388A - Method and system for changing forward traffic channel power allocation during soft handoff - Google Patents

Abstract

A system and method for adjusting forward traffic channel power allocation in a communications system (2), wherein signal qualities of pilot channels respectively transmitted by multiple base stations (12, 14, 16) in an active set of a mobile station (18) are mesured by the mobile station (18), compared to a signal quality standard, and the comparison results reported to a system controller (10), thereby to indicate which of the pilots at the mobile station (18) surpass the standard. The system controller (10) then adjusts the forward channel power allocation based on the comparison results.

Description

METHOD AND SYSTEM TO CHANGE THE POWER ALLOCATION OF THE IDA TRAFFIC CHANNEL DURING TRANSFER SOFT BACKGR OF THE INVENTION I. FIELD OF THE INVENTION The present invention relates to cellular communication system, and more particularly, to methods and apparatus for changing the power allocation of the outb traffic channel in a multiple access cellular communication system by division of code (CDMA).

II. Discussion of the Backgr Art In a cellular telecommunications system CDMA, a common frequency band is typically used to communicate from a mobile station to a set of base stations, and another common frequency band is typically used to communicate to the mobile station from a set of base stations. In other cases, a common set of frequency bands can be used to conduct communications. A primary benefit of transmitting multiple communications over a common frequency band is an increase in the capacity of the cellular telephone system. The IS-95 standard, promulgated by the Association of the Telecommunications Industry (TIA), is an example of a highly efficient CDMA air interface, which can be used to implement a cellular telephone system. The set of communications conducted on the same bandwidth in the CDMA cellular telecommunications systems, are separated and distinguished from one another by modulation and demodulation of the transmitted data using known pseudorandom (PN) noise codes for the systems of reception and transmission. The other communications appear as backgr noise during the processing of any particular communication. Because the other communications appear as backgr noise, CDMA protocols, such as the IS-95, often employ extensive transmission power control, in order to use the available bandwidth in a more efficient manner. . The control of the transmission power maintains the transmission power in each communication close to the minimum necessary, in order to conduct the communications successfully. Such transmission power control facilitates the processing of any particular communication, reducing the level of backgr noise generated by the other communications.

Another benefit of having base stations transmitting to mobile stations over the same frequency band, and of having mobile stations transmitting to a base station in a second frequency band, is that "flexible transfer" can be used for the transition of a mobile station of the coverage area of a first base station, to the coverage area of a second base station. Flexible transfer is the process of simultaneously interconnecting a mobile station with two or more base stations. The flexible transfer can be contrasted with the strict transfer during which the interconnection with the first base station is terminated before the interconnection with the second base station is established. As one might expect, flexible transfer is generally more robust than strict transfer, because at least one connection is maintained at all times. The methods and systems for conducting flexible transfer in a CDMA cellular telephone system is described in U.S. Patent No. 5,101,501, filed November 7, 1989, entitled "Method and System for Providing a Flexible Transfer and Communications in a System Cellular Telephony CDMA ", and US Patent No. 5,267,261 entitled" Mobile Flexible Held Transfer in a CDMA Cellular Telephone System ", both granted to the beneficiary of the present invention and incorporated herein by reference. In accordance with the flexible transfer procedure described in the patents referred to above, each base station transmits a respective pilot channel that is used by the mobile stations to obtain a synchronization of the initial system, and provide a tracking of the time, frequency and robust phase of the signals transmitted at the cell site. The pilot channel transmitted by each base station uses a common dispersion code (ie, a pseudonoise sequence), but uses a different phase shifting of the code, so that the mobile station can distinguish the pilot channels transmitted from the base stations respective. During a flexible transfer, two or more base stations transmit the same data as the one-way link to the mobile station. The mobile station receives the signals from the set of base stations and combines them, a method and apparatus for performing such combination, is described in US Patent No. 5,109,390, filed on November 7, 1989, entitled "Diversity Receptor in a System of Cellular Telephony CDMA ", granted to the beneficiary of the present invention and incorporated herein by reference, describes a method for combining diversity for use in a CDMA cellular telephone system. Although flexible transfer provides a more robust connection, in some cases flexible transfer has a negative effect on the total capacity of the CDMA cellular telephone system. This is because the multiple transmissions of the forward link generated during a flexible transfer can increase the total transmission power, used to drive the corresponding communication. This increased transmission power increases the total background noise generated by the system, which, in turn, decreases the overall capacity of the system. If the flexible transfer increases or decreases the capacity of the system, it typically depends on the medium that the mobile station is experiencing during the flexible transfer. If the mobile station is experiencing a fading medium, the increased diversity provided by the flexible transfer is generally beneficial to the performance of the system, because the signals generally fade independently.

When the station is in a non-fading medium, however, the diversity of the data source is typically redundant. Therefore, for non-fading media, the benefit provided by the diversity of the increased signal source typically does not justify the total increase in transmit power caused by the flexible transfer. Thus, the present invention is directed to improving the performance of a CDMA telecommunications system, optimizing the configuration of a CDMA communication system during a flexible transfer, in a multi-carrier medium, or both, in response to the medium in which it is transmitted. is driving the communication.

BRIEF DESCRIPTION OF THE INVENTION Accordingly, an object of this invention is to provide a novel method for reducing a total amount of the forward traffic channel power transmitted to a mobile station during a flexible transfer. Another object of the invention is to provide a system that implements the aforementioned method.

Another object of the invention is to determine the medium in which the mobile station is operating during flexible transfer, and optimize the flexible transfer configuration in response to that determination. The invention is equally applicable to a one way link with multiple carriers. Accordingly, an object of this invention is to provide a novel method for reducing a total amount of the forward traffic channel power, transmitted to a mobile station with a forward link with multiple bearers. Another object of the invention is to provide a system that implements the aforementioned method. Another object of the invention is to determine the medium in which the mobile station is operating, and to optimize the configuration of the forward link with multiple carriers, in response to that determination. The present invention is equally applicable to systems, which employ both flexible transfer and a forward link with multiple carriers. The present invention provides a novel method and system, wherein a mobile station often sends a vector message of bits to a system controller, indicating the quantized and measured qualities of the signal (e.g., signal to interference ratios) of the pilots. of each base station in an "active set" of pilot channels, tracked by the mobile station. The mobile station generates the vector message of bits by verifying the respective signal qualities of the pilots, comparing the qualities of the respective pilot channel, against a standard, and transmitting the vector message of bits to the respective base stations, in the active set of mobile stations, which then sends the information in the vector message of bits to a system controller. In response, the system controller issues an order to the base stations in the active set of mobile stations, adjusting selected ones of the powers of the respective code channel of the base stations, according to the respective pilot channel qualities, reported in the vector message of bits generated by the mobile station. Because the forward traffic channel includes respective code channels of the base stations in the active set of mobile stations, the reduction of the transmission power of the respective code channels reduces the transmitted power of the forward traffic channel . Therefore, the total capacity of the CDMA communication system is increased, as a result of irradiating the minimum required traffic channel power, for proper reception in the mobile station. By rapidly communicating the qualities of the pilot channel observed to the system controller, the CDMA system is able to rapidly reoptimize system resources, in response to environmental changes, to maximize the communication capacity of the system. In an alternative embodiment of the invention, which employs a link with multiple carriers, the mobile station sends one bit for each carrier, or alternatively, one bit for each antenna. Additionally, the base station adjusts the power in each carrier, independently.

BRIEF DESCRIPTION OF THE DRAWINGS A more complete appreciation of the invention and many of the attendant advantages thereof, will be readily obtained as the same is better understood, with reference to the following detailed description, when considered in connection with the accompanying drawings. , where: FIGURE 1 is a block diagram of an exemplary CDMA cellular telephone system, in accordance with the present invention; FIGURE 2 is a graph of the quality of the pilot channel versus time and a region of a flexible transfer represented in the graph; FIGURE 3 is a block diagram of a mobile station; FIGURE 4 is a graph showing the exemplary probability of the frame error rate vs. Eb / No for several transmitting base station numbers, as received by a diversity receiver with N digits; FIGURE 5A is a graph showing the Ec / Io vs. time within a flexible transfer region for three exemplary pilots; FIGURE 5B is a graph similar to that shown in FIGURE 6a, with the addition of one. threshold signal? r, which is formed below the highest pilot level; FIGURE 6A is a diagram of a first data structure for the vector message of bits, indicating the quality of the pilot channel; FIGURE 6B is a diagram of a second data structure for the vector message of bits, indicating the quality of the pilot channel; FIGURE 6C is a diagram of a third data structure for the vector message of bits, indicating the quality of the pilot channel; FIGURE 7 is a diagram of a message sequence for reducing a total amount of the forward traffic channel power, transmitted from the base stations in an active set when it is being transmitted with an excess of power; FIGURE 8 is a flow chart of an alternative message sequence for reducing the total amount of power of the forward traffic channel transmitted from the base stations in an active set when it is being transmitted with an excess of power; FIGURE 9 is a diagram of an outbound link with multiple carriers; FIGURE 10 is a block diagram of a transmitter of a forward link with multiple carriers; and FIGURE 11 is a block diagram of a receiver of a forward link with multiple carriers.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, where similar reference numbers designate identical or corresponding parts throughout the various views, and more particularly to FIGURE 1 thereof, a communication system is illustrated 2 , which is preferably a cellular telephone system, although it is equally applicable in a public secondary exchange (PBX), a personal communication services system (PCS), a satellite-based communication system, an indoor wireless network or a outdoor wireless network. System 2 uses modulation and demodulation techniques with code division multiple access (CDMA) in communications between system resources. A system controller (selector) 10, commonly referred to as the mobile telephony switching office (MTSO), includes an interface and processing circuitry to provide control of the system to a base station assembly 12, 14, 16, 17 and 19. The system controller 10 also controls the routing of telephone calls from a public switched telephone network (PSTN) to the appropriate base stations 12, 14, 16, 17 and 19 for transmission to the appropriate destination. A connection to or from the PSTN can be a wireless, fiber optic, or "wired" communication (eg, coaxial or twisted pair cable). The system controller 10 communicates with the private and public networks, which include data networks, multiple media networks, and other private and public communication entities. further, the system controller 10 communicates with and from other base stations, which are not shown in FIGURE 1. The system controller 10 communicates with the base stations 12, 14, 16, 17 and 19 by various means, such as such as dedicated telephone lines, fiber optic links, coaxial links, or radiofrequency (RF) communication links. The base stations 12, 14 and 16 communicate with other systems such as the mobile ("mobile") station 18, via wireless CDMA communications with a single carrier. The base stations 17 and 19 communicate with other systems such as the mobile station 21 via a link with multiple carriers, comprised of three CDMA signals illustrated by the arrows 26a-c. the mobile station 21 communicates with the base stations 17 and 19 via a reverse link with a single carrier 28. It should be noted that a link of. One way with multiple carriers may consist of more than three carriers, or may consist of less than three carriers. FIGURE 1 also illustrates a system with multiple carriers and one with direct dispersion with a single carrier, more conventional, coexisting in the same system. It should be noted that although this is possible, it is preferable that a system uses only one type for the outbound link.

The arrows 20a and 20b illustrate the respective return and return links between the base station 12 and the mobile station 18. The arrows 22a and 22b illustrate the return and forward links between the base station 14 and the mobile station 18. Similarly, the arrows 24a and 24b illustrate possible round-trip links between the base station 16 and the mobile station 18. Although the cross-links between the respective base stations 12, 14, 16 are not shown in FIGURE 1, or a radio frequency or direct connection of the controller 10 to the mobile station 18, such possibilities are included within the inventive aspects of the present invention. The base stations 12, 14 and 16, each transmit traffic data via a Walsh code channel to the mobile station 18, in the communication outgoing links 20b, 22b and 24b, when the system controller 10 allocates the stations base 12, 14 and 16 to the active set of mobile stations and instructs the respective base stations to establish an interconnection with the mobile station 10. The code channel assigned for communication with a mobile station 10 is also referred to as the channel of traffic. Each of the code channels transmitted from different base station to the mobile station, contains redundant information and is available in the mobile station 10, to combine the respective code channels using a diversity combining mechanism (explained in more detail at the moment) . To increase the speed of the outbound link to a mobile station, multiple code channels can be used from the same base station. In this case, the union of code channels is called the traffic channel. The forward link signal includes the joining of the code channels including the set of traffic channels and the additional control channels, such as the pilot, synchronization and paging channels. The present invention reduces the transmitted power of the forward link signal by reducing the time that the traffic channels are active during a flexible transfer. The base stations 12, 14 and 16 also respectively transmit the pilot channel to the mobile station 18, together with the forward communication links 20b, 22b and 24b. The pilot channels distinguish from the traffic 'channels transmitted from the same base station by the different Walsh codes. The respective pilot channels of the different base stations are distinguished from each other by the changes in the pilot PN code. In the absence of blocking or fading, the pilot channel received at the mobile station 18 of the base station 16 would be expected to be larger in the received signal strength than that of the base stations 12 or 14, because the mobile station 18 is closer to base station 16. Alternatively, instead of a separate code channel (Walsh code), for the pilot, the pilot may be included or multiplexed in traffic channel flows, which are sent to the individual mobile stations. Inclusion can be done using special pilot symbols, or an auxiliary signal. When the pilot is used, there is typically a common pilot, which is used for the initial acquisition of the system and to detect when a flexible transfer has to be made. Alternatively, separate pilots can be transmitted on a base per traffic channel or per group of traffic channels. When the mobile station 18 in a flexible transfer region (e.g., when moving from a coverage region of at least one base station to at least another base station), the system controller 10 dispatches a transfer address message that includes a list of base stations assigned to the active set of mobile stations. The transfer address message may also include auxiliary information, such as the thresholds of the transfer (e.g., the additional threshold and the call threshold), which is useful for the mobile station after performing the transfer. As described in the applications referred to above and in the IS-95 standard, the active set contains pilots of the base stations, with which an interconnection with the mobile station has been established. The candidate set contains pilot channels that have been recently detected with sufficient force by the mobile station, and the candidate set contains pilot channels of the base station, which are known to be in the same geographical region. Knowing which pilot channels will likely have a reasonable strength (i.e., knowing which base stations are assigned to the candidate and neighbor set of the mobile station), the processing required in the mobile station is reduced in that the mobile station can search more frequently for the channels pilot corresponding to the base stations in the candidate and neighbor sets of the mobile station, as well as in the active set. FIGURE 2 is a graph showing the relative quality of the pilot channel that can be observed by the mobile station 18 from cells 12, 14 and 16, as shown in FIGURE 1. The graph in FIGURE 2 graphs the energy per chip PN (Ec) by total received power (lo) in the mobile station 18 vs. time, for three exemplary pilot channels of the base stations 12, 14 and 16. As shown in FIGURE 2, the pilot of the base station 16 degrades in the quality of the signal with the increase in time, indicating that the mobile station 18 is moving away from base station 16. Conversely, the pilot of base station 12 improves signal quality over time, implying that mobile station 18 is moving towards base station 12. The pilot of the base station 14 remains relatively constant in signal quality, indicating that the mobile station 18 is moving along with a coverage perimeter of the base station 14. The area of interest in FIGURE 2 is the region of flexible transfer. In, the region of the flexible transfer, the mobile station 18 and the controller of the system 10 communicate with each other to determine which base stations should be within the active set of mobile stations, based on the relative qualities of the pilot channel of the mobile station. the cells 12, 14 and 16. In the illustrative example, the pilot channel of the base station 16 is originally in the active set of mobile stations, because the level of the pilot channel of the base station 16 is above the level of additional threshold. However, at the end of the region of the flexible transfer, the pilot of the base station 16 falls below the threshold level of fall for some period of time. In response, the system controller 10 causes the base station 16 to fall from the active set by the mobile station that is communicating to the system controller 10, via a pilot force measurement message. Because the pilot of the base station 14 never exceeds the additional threshold level, the base station 14 is not added to the active set. In contrast, the base station 12 exceeds the additional threshold level for the period of time necessary, and is therefore added to the active set as determined by the system controller 10, in response to a force measurement message. of the pilot, generated by the mobile station 18. Towards the end • or end of the flexible transfer region, only the signal from the base station 12 remains within the active set of the mobile station 18. Frequently, the pilot channel received in a deficient manner it is detected above the fall threshold with a frequency sufficient to maintain the corresponding base station in the active set, although the corresponding traffic channel contributes little to the quality of the reception in the mobile station. This is particularly true in a medium with slow fading. In the case of medium with slow fading, the levels of the signal received from the base station change slowly relative to each other. Typically, one base station is stronger than another for a while, and vice versa. The rate of fading is not fast enough to obtain the benefit of short term diversity. Thus, it would be preferable to transmit from the strongest base station and not from the weakest base station. The present invention seeks to reduce the transmission time of the code channels from some base stations in a fading medium, in order to decrease the total transmitted energy generated by the associated communication. Reducing the total transmitted energy of a particular communication improves the total capacity of the system. It should be noted that one could use the transfer procedures, which would remove the base stations of the active set, thus reducing the transmitted power. However, this process requires considerable signage in the infrastructure and, therefore, is relatively slow.

This makes it difficult to quickly switch to transmit from another base station when its signal becomes the strongest signal. Another case in which this invention provides a benefit, is when a base station is received in the mobile station at a lower signal level than the other base station, but which is still above the call threshold. In a medium with little fading, it is preferable to transmit only from the base station whose signal is being received more strongly in the mobile station. However, removing the base station from the active set and then using the transfer procedures to restore it to the active set adds a considerable delay in case this pilot becomes stronger. This delay reduces the quality of the link, and may result in calda calls. FIGURE 3 is a block diagram of the mobile station 18. An antenna 30 is coupled through a diplexer 32 to an analog receiver 34 and to the amplifier of the transmitted power 36. The diplexer 32 cooperates with the antenna 30, of In this manner, simultaneous transmission and reception is achieved through the antenna 30. While receiving RF energy from the respective base stations 12, 14 and 16 (FIGURE 1), the antenna 30 receives the pilot and code channel signals routed to through the diplexer 32 to the analog receiver 34. The analog receiver 34 receives the RF energy from the diplexer 32 and implements an open circuit power control function to adjust the transmitted power of the mobile station for the transmissions on a return link (it is say, mobile station to base station). More particularly, receiver 34 generates an analog power control signal, which is provided to a transmitted power control circuit 38, as discussed in U.S. Patent No. 5,056,109, entitled "Method and Apparatus for Controlling Power of Transmission in a Cellular Telephone System CDMA ", assigned to the beneficiary of the present invention and incorporated herein by reference. An adjustment of the closed-circuit power control is developed by the control processor 46, using a power-control bit flow of the return link, which was transmitted on the forward link and demodulated via the digital data receivers. 40, 42 and 45. The analog receiver 34 converts the received RF energy into a baseband signal and digitizes the baseband signal. The digitized output of the analog receiver 34 is provided to a search receiver 44 and the digital data receivers 40, 42 and 45, which operate under the control of the control processor 46, receive the code channels of the respective base stations and provides respective outputs to a diversity combiner / decoder 48. The diversity combiner / decoder 48 combines the respective output signals of the receivers 40, 42 and 45, based on a selected combination scheme, discussed in more detail below. Although the three digital data receivers 40, 42 and 45 are shown in FIGURE 3, the diversity combiner / decoder 48 is typically equipped to interface with a number of additional digital data receivers. Preferably, the number of digital data receivers included in the mobile station 18, is equivalent to the maximum number of code channels (separately counting the direct and path, multiple signals produced from each code channel) that the mobile station will use in your combination scheme. As will be discussed, an additional diversity gain is possible with the inclusion of additional data receivers, and the present invention is applicable to any number of digital data receivers (or digital data receiver with multiple channels).

The digital data receivers 40, 42 and 45 cooperate with the diversity combiner / decoder 48 to form a receiver structure in the form of a "rake". The diversity combiner / decoder 48 cooperating with each of the respective receivers 40, 42 and 45, serves as three "digits" in a rake. More particularly, the receivers 40, 42 and 45 can be set by the control processor 46 to receive the code channels of different base stations, or a multi-path signal of a common base station. Thus, all three receivers 40, 42 and 45 can be used to receive the code channels of three different base stations, or a signal code channel of a base station, which arrives via three different signal paths (i.e. three signals with multiple trajectories). It should be clear that the receivers 40, 42 and 45 can be used to receive any combination of code and multi-path cardals from different base stations. The structure of the rake receiver can also be implemented in numerous other configurations based on, for example, several single channel receivers, multi-channel receivers (i.e., having at least one channel) and combinations of the diversity combiner. In addition, the function of the diversity combiner could be incorporated into the control processor 46, or one of the receivers 40, 42, 44 and 45. In the preferred embodiment, the output of the diversity combining / decoding circuit 48 is passed to a deinterleaver and a decoder. The output of the decoder is typically passed through a control unit, which divides the received data streams into end user data and control data. The end user data is supplied to a data device, such as a voice frequency encoder. The data output of a data device, such as a voice frequency codee, is transmitted on a link back to the base stations in the active set of the mobile stations - the output of the user's digital baseband circuit. , is a baseband signal which is formatted, coded, interleaved and passed to a transmission modulator 52, where it is modulated. An output of the transmission modulator 52 is passed through a control device of the transmitted power 38, under the control of the control processor 46. The control circuit of the transmitted power 38, adjusts the output power of the mobile station 18 (FIGURE 1), based on the signal of the power level provided by the analog receiver 34 and the control bits of the closed circuit power, and an output RF signal is passed to an amplifier of the transmitted power 38, which amplifies the output signal and passes the amplified output signal through a diplexer 32 and is transmitted through the antenna 30. The digitized IF signal of the analog receiver 34 contains the signals of the code channel and the transmitted pilots by the base stations in the active set of the pilot, together with other CDMA signals, which act as interference to the mobile station 18. The function of the receivers 40, 42 and 45, is to correlate IF samples with the appropriate PN sequence. This correlation process provides the "processing gain", which improves the signal to interference ratio of the intended signal for the mobile station, by matching the PN sequence used in the respective code channels, to encode the message that is being sent to the base station. The unproposed signals that have not been coded with the matching PN sequence are "scattered" by the correlation process thereby decreasing the signal to interference ratio for the unproposed signals. The output of the correlation is detected consistently using the pilot carrier as a carrier phase reference. The result of this detection process is a sequence of coded data symbols. The search receiver 44, under the control of the control processor 46, scans the received pilot channels and the pilot paths with multiple paths of the base station via direct paths and reflected paths (eg, multiple paths). The scan receiver 44 uses a ratio of the pilot energy received per chip (Ec), to the total received spectral density, noise and signals, denoted as Ec / I0, as a measure of the received pilot's quality. The receiver 44 provides a signal measuring the signal strength to the control processor 46, indicative of the respective pilot channels and their forces. The diversity combining / decoding circuit 48 adjusts the timing of the received signals introduced in alignment and the summing together. This addition process can be preceded by the multiplication of the respective input signals, by a weighting factor corresponding to the relative signal strengths of the pilot channels, corresponding to the respective inputs. The weighting factor is based on the strength of the pilot, because it is presumed that the quality of the respective signal of each pilot corresponds to the quality of the signal of the signals transmitted in the code channel of the respective base stations. When the weighting factor is used, the combiner implements a combination scheme of maximum relationship diversity. The flow of the resulting combined signal is then decoded using an outflow error detection decoder, which is also contained within the diversity combiner / decoder circuit 48. The pilot-based weighting method works well when the base stations in the active set transmit the signals of the code channel to the mobile station in a proportion equal to the pilot signal. That is, the ratio of the power of the code channel to the pilot power is the same in all members of the active set. If the relationship is not the same, then other methods of weighting may be preferable. For example, the base station may send to the mobile station, in a signaling message or by some other means, the ratio of the traffic channel to the power of the pilot channel that is used by all the base stations in the active set. Next, if the relative fraction for the base station j is 0Cj, the mobile station can combine the code channels using the weights -Ja, where y-is the relative received power of the pilot for the base station j in the mobile station. Alternatively, the mobile station can estimate a-, or a ^ of the signal received from the base station j. The baseband circuitry 50 includes voice coder data interfaces (vocoder), and other baseband processing features. In addition, the user's digital baseband circuit 50 is interconnected with the I / O circuits, such as a handset, which inputs a speech signal to a digitizer and a vocoder (voice encoder) contained therein. The output of the digital baseband circuit of the user 50 is provided to a transmission modulator 52, which modulates a signal encoded in a PN car signal, whose PN sequence corresponds to an assigned address function for the call that is output . This PN sequence is determined by the control processor 46, of the call start information, which is transmitted by the base station (12, 14 or 16) and decoded by the receivers (40, 42 or 45). The output of the transmission modulator 52 is provided to the control circuit of the transmission power 38, where the transmit power of the signal is controlled by the power control signal 3 (5).

Analogously, provided by the receiver 34. In addition, the control bits are transmitted by the base stations in the form of power adjustment commands, to which the control circuit of the transmitted power 38 responds. The power control circuit Transmitted 38 produces the modulated signal of the power control to the amplifier circuit of the transmitted power 36, which amplifies and converts the modulated signal to a frequency FR. The amplifier of the transmitted power 36 includes an amplifier, which amplifies the power of the modulated signal to a final output level. The amplified output signal is then passed to a diplexer 34, which couples the signal to the antenna 30 for transmission to the base stations 12, 14 and 16. The signals intended for the system controller are received by the base stations 12, 14 and 16, and are passed respectively to the controller of the system 10, where they are combined. FIGURE 4 is a graph of diversity receiver performance, measured in the probability of frame error rate, versus Eb / No, where the diversity receiver implements the maximum ratio combination. Four exemplary curves are shown which represent the probability of the frame error rate, which respectively represent a mobile receiver having one digit (M = l), two digits (M = 2), three digits (M = 3) or four digits (M = 4) configured to receive signals from a corresponding number of base stations. Comparing the curves for M = l and M = 2, the performance of a receiver that has two digits and that processes two trajectories, is better than that for a receiver that processes a trajectory. This comparison is made by observing, for a given frame error rate (ie, the dotted line), a distance between the respective probability of the error curves of the frame. In the exemplary chart, an improvement in performance is shown by the distance M? _2. Similarly, if a diversity receiver having three digits is used by the mobile station, an improvement in the performance of M2_3 is achieved, where generally M2_3 is less than the improvement in the performance of M? _2. In a similar way adding a fourth digit to a receiver of 'diversity, provides an improvement in performance as shown by M3_. It should be noted that M3_4, is smaller than M2-3 and M? _2. Thus, if the mobile station were the only mobile station in the CDMA system, diversity receivers having a large number that is increased by digits receiving a corresponding number of transmissions from the base stations, would provide continuous improved performance, though, the improvement that reaches minimum returns for M, is a large number. In addition, the aforementioned performance relationship assumes that none of the digits contribute to noise alone (or practically only noise) to the combination process. The absolute amounts of improvement depend on the communications conditions (for example, amount of fading), type of fading, noise impulsivity, proximity of the base station, etc. ). During flexible transfer, the capacity of the system is affected differently by exploiting the processes of diversity combination in the one-way link, and in the return link. For example, in the return link, the mobile station transmits to the base stations, 12, 14 and 16 through the paths 20a, 22a and 24a (FIGURE 1) respectively. Each of the base stations receives the transmission from the mobile station 18, and sends the same to the system controller (selector) 10 which combines the respective signals provided by the base stations 12, 14 and 16, using a combination process of diversity. Because only one mobile station 18 is transmitting, the capacity of the system is not adversely affected by the use of the diversity combination. 3J In one way link, however, the mobile station 18 combines different signals (all having the same coded information), transmitted from the base stations 12, 14 and 16. Various methods are known to combine in the art, including the combination of maximum ratio, the gain combination equivalent, and simple selection, where one signal is selected for processing, and the other signals are discarded. Providing an additional, and perhaps excessive, number of base stations to the active set of the mobile stations will certainly improve the performance observed in that mobile station, but may actually degrade the capacity of the total system of the CDMA system, since the additional transmissions of the base stations communicating to the first mobile station will appear as background interference to a second mobile station. The utility of a particular code channel depends on a variety of factors, including its strength relative to the code channels of other base stations. The total irradiated power of the CDMA communication system is typically less if there is sufficient gain in diversity. However, as recognized in accordance with the present invention, the total power which is radiated is typically greater than what is required for adequate performance, even if the additional diversity is not needed. Whether an increase or decrease in the amount of power radiated from each of the base stations is affected, depends on the characteristics of the transmission paths between the base stations and the mobile station. According to one embodiment of the invention, the total transmitted power of the CDMA system is adjusted to a more optimal operating point by increasing the coordination between the mobile station 18 and the system controller (selector) 10. Follow a description of how to collect in the mobile station the required information so that the system can operate at a higher capacity. FIGURE 5A is a graph of Ec / Io versus time for a flexible transfer region, in which three A, B and C pilots of the respective base stations are included in the active set of the mobile station. During the flexible transfer region, as seen in FIGURE 5A, changes in the respective communication channels for pilots A (shown by a dotted line) B, (shown by a shaded line), and C (shown by a solid line), causes variations in the strength of the signal and therefore in the signal-to-noise ratios which cause the respective pilots A, B and C to fluctuate. It is these fluctuations that offer significant potential for improving the gain of diversity, and the present invention teaches how to exploit the gain of diversity to maximize the capacity of the system by changing the designation of the power of the forward traffic channel in a manner fast The relative pilot quality strengths (pilot quality) of pilots A, B, and C fluctuate from frame to frame, as shown in FIGURE 5A, any of signals A, B, and C varies in SNR relative to the other signs. For example, in the first frame, pilot A provides the highest SNR, while pilot B provides the lowest SNR. However, in Table 2, the relative signal-to-noise ratios of pilots B and C are crossed (as shown in FIGURE 5A), and at the end of Table 2, the SNR of pilot B is greater than that of the pilot. C. FIGURE 5B is identical to, FIGURE 5A, but includes a level? R (shown as a crossed line "x"). calculated by the control processor 46 (FIGURE 3) of mobile station 18, where? R is representative of a fixed level? below the strongest signal-to-noise ratio of pilots A, B and C, in the active set of mobile stations. Preferably,? R is a unique number generated by the control processor 46, although 3 alternatively variations of? r (ie, a plurality of?) may be employed, so that the? they are used to solve in a finer way the qualities of the relative signal of the pilots. The control processor 46 calculates a threshold signal? R, preferably continuously, although a discrete or piece-by-piece implementation of alternative? R may occur. As shown in FIGURE 5B, during the first frame, only the pilot A is at or above the threshold signal? R, which, in this example, is adjusted by the pilot A itself (ie, the pilot A has the strongest SNR and therefore? R is based on a level? DB below the SNR adjusted by pilot A). It is also noted that signals B and C are not at or above the level of the signal? R. Therefore, FIGURE 5B indicates in table 1 that the pilot A (as denoted by the character "A" written on top of the "TIME" axis in the first frame) is at or above the signal ? r, and has the highest SNR average, over the interval of the last table. In Table 2, the strongest SNR is that of signal A, followed by pilot B, and the minor pilot is C, all of which are above r, at the end of the frame. In Tables 3 and 4, only pilots A and B are above? R. In table 5, pilot C has the strongest SNR (and therefore the? R is calculated based on pilot C). Pilot A is the next strongest signal, and is greater than the SNR of pilot B, all of which are above? R. Calculating? R and comparing? R with each of the respective signals of the base stations in the active set, the mobile station has effectively collected a significant amount of information with respect to the particular communication channels, within a given frame. This characterization of the communication channels can be exploited by the mobile station, by configuring the diversity receiver of the mobile station, and the combiner in order to optimally detect the signals transmitted from the respective base stations. Additionally, according to one embodiment of the invention, the performance of the CDMA communication system is also optimized by communicating the best signal qualities of the pilots, within the active set to the system controller on a frequent basis, so that the system controller can make commensurate adjustments of the designation of the power of the outbound traffic channel between the base stations in the active set. The information is quickly communicated to the system controller 10 (FIGURE 1) because the optimal number and selection of the transmitting base stations does not remain constant since the relative SNR of the signals of each base station changes rapidly from frame to frame as is illustrated in FIGURE 5. It should also be noted that the value? which is used to calculate? r, may be pre-stored in the mobile station, or may be sent to the mobile station via a signaling message or some other control method. It should also be noted that FIGS. 5A and 5B are described in the context of tables, which may correspond to the frames used for data frame formation, interleaving and, coding on the traffic channel as described in the standard. IS-95. However, this is not necessary in this invention, and the frames shown in FIGS. 5A and 5B may not correspond to any particular processing interval, and may be either shorter or longer than the exemplary value of 20 milliseconds. Additionally, the various transmissions described above are generated by different base stations. Nevertheless, the invention is also applicable to any radiating element for a forward link signal. In particular, the invention is applied to different antennas in the same base station that radiates the same signal. For example, the signals A, B and C in FIGURES 5A and 5B may be of different antennas, from the same base station, as would be the case where there are three antennas in a base station. It should also be understood that the set of signals A, B and C shown in FIGS. 5A and 5B can be of any combination of base stations or antennas in a base station. For example, the signals A and B could be from two different transmit antennas in the base station 17 and the signal C could be transmitted from the base station 19. The signals A, B and C could be one-way links of multiple bearers, all transmitted from the same base station, or could be the signals from different antennas that radiate the one-way link with multiple carriers. For example, if the base station 17 transmitted three carriers of two antennas, then the signal A could consist, of two carriers and the signal B of a carrier. The signal A could be comprised of two different separate bearer signals, however, in this example both of these bearers are radiated from the same antenna, and will be received by the mobile station essentially at the same level, provided they are transmitted on the same level. It should also be clear that in the real system there can be much more than three signals (which are shown in FIGS. 5A and 5B), which the mobile station is tracking. To provide the system controller 10 (FIGURE 1) with this information on a fast basis, the present invention provides a novel communications protocol between a mobile station and the system controller 10 discussed herein, with reference to FIGURES 6A- 6C. FIGURES 6A-6C show alternative forms of a signaling or control message, in the form of a bit vector message reported to the system controller (selector) 10, through the return link signal transmitted from the mobile station 18 to selector 10, by means of one or more base stations (12 and 14). The bit vector message is preferably transmitted on a frame-by-frame basis, although a more frequent report as well as a less frequent report is not possible. In one embodiment of the invention, a return link signal with multiple channels is employed, wherein the return link signal is comprised of a set of orthogonal code channels defined by a set of Walsh codes in a manner similar to one way link In this return link implementation with multiple channels, the message of the bit vector is preferably communicated through one of the orthogonal code channels on the return link, to minimize the delay time before the controller of the bit vector is communicated. system can act on the information contained in the bit vector message. A system and method for transmitting data using such a return link signal is described in the copending United States patent application, no. of series 08 / 654,443, entitled "CDMA INAL MBR COMMUNICATIONS SYSTEM WITH HIGH SPEED DATA", filed on 5/28/96, assigned to the beneficiary of the present invention and incorporated herein by reference. In an alternative embodiment of the invention, a return link signal of the unique code channel is used, as used in a system in accordance with IS-95. The bit vector message is preferably transmitted together with the other user data, within the single code channel, via time multiplexing or drilling of the data vector bits in the PN code of the return link. FIGURE 6A shows a data structure for a bit vector message of the pilot quality, generated by the mobile station, and transmitted to the system controller 10 via the base stations. In particular, FIGURE 6A shows a 10-bit vector message, which is short in length, although capable of reporting to the system controller 10, which of the pilots in the active set of mobile stations has the qualities of the signal at or above a given standard (for example, the threshold signal? r in FIGURE 5B). The bit vector message does not need to be limited to 10 bits, and may be in other formats than the bit vector although it is desirable to have a short message. In order to reduce the number of bits transmitted, the vector message of bits presumes an array of the respective pilot channels based on an initial order of the pilots identified to the mobile station, of the system controller in an address message of the transfer. The CDMA IS-95 standard allows up to six members (pilots) in the active set, all of which can be accommodated in the vector message of pilot quality bits. In FIGURE 6A, the pilot having the best (ie, the highest interference signal ratio) as judged by the process described with reference to FIGURE 5B, is identified by an index of the three-bit data field on the which, uniquely identifies its position as originally reported to the mobile station in the transfer address message. The index is denoted in FIGURE 6A by a group of three-bit data Ii, I2 and I3. Thus, if the pilot channel of the second base station reported to the mobile station in the last address message of the transfer is received with the highest SNR, the three-bit index is set to two (binary 010), or alternatively 1 if the index runs from 0 to 8. The bit fields U1, U2, U3, U4, U5 and U6 each refer to the respective pilots as originally enlisted in the transfer address message, and indicate whether the pilot channel corresponding was received above the threshold signal? r. For example, the bit in the data fields U1-6 is set to (or alternatively to 0), indicating to the system controller 10 that the pilot channel corresponding to that bit position is being received equal to or above. the threshold signal? r. In particular, if U1 is set to 1, the system controller 10 would recognize that the first driver identified in the last address message of the transfer has a base signal noise ratio that is equal to above r r, as calculated by the control processor 46. U2"6, is also adjusted by the processor 46, preferably on a frame-by-frame basis and transmitted to the system controller 10 via the base stations in vector bit messages.

The last element of the data field Hm is the sequence number of the address message of the transfer. The Hra data field is used to provide the system controller 10 with an identification of the active set, to which the mobile station refers. Hm could be several bits long, alternatively it could be a single bit. For the case of a single bit Hm could be the last bit in the sequence number. Thus, if the base station sent messages from the sequence address with sequence numbers equal to "100" followed by a binary "101", then the mobile station would return a "1" in H if it were referring to the address message of the transfer with the sequence number "101", and would return to a "0" in Hm, if it was referring to the address message of the transfer with a sequence number "100". Including the sequence number, the base station can positively determine which pilot the mobile station is referring to in the three-bit data field Ii, I2 and in the set U1, U2, U3, U4, U5 and U6. In one embodiment of this invention, which includes a forward link of multiple bearers, the bit vector of U1, U2, U3, U4, U5 and U6 can be expanded to NxM bits, where N are the possible base stations in the active set, and there are M possible antennas in the base station. Alternatively M may correspond to the number of possible one-way links with multiple carriers in a base station. In this modality, the mobile station reports the strongest of the NxM one way carriers with multiple carriers, with the vector Ii, I2 and I3 (which may need to be larger to take into account the need to identify the largest of the points). NxM), and reports which of the other channels with multiple bearers are above r? Using the vector U1. In an alternative mode the mobile station reports the strongest base station, instead of the strongest carrier, using the vector Ii and then reports which other channels with multiple bearers are above r? Using the vector U1. It should be noted that? R may be with respect to the strongest base station or the strongest bearer over all the base stations in the active set of the mobile station. It should also be noted that the strongest base station can be determined by summing the pilot's Ec / Io of all one-way carriers in a base station with multiple carriers, as can be done with the multi-path components of the same carrier, as it is commonly used in IS-95. Thus, the total strength of a base station is given by summing the EC / I'o of all the forward link carriers and all the multipath components in a particular carrier. In response to the message of the bit field, the system controller 10 receives the message of the measured power and, will be described herein, determines which of the signals in the active set to remove from the forward traffic channels, and which of the base stations keep transmitting. That is, the system controller 10 identifies which base stations are transmitting signals that are being received below the threshold signal ρ r using the message of the bit field. The controller of the system 10 then instructs the identified base stations to stop the transmission of the traffic canai directed to the corresponding mobile station, which in turn, reduces the transmission power of the outbound link signal generated by these. base stations. In an alternative mode, the base station, in place of the system controller, can receive the message and determine if it will be transmitted to the outbound link. This method decreases the delay although it may be less reliable than when the mobile station is in a flexible transfer, since all base stations (or base stations that should be transmitting the forward link) may not receive the transmission of the return link . The base stations respond by not transmitting the traffic channel during the next data frame addressed to the corresponding mobile station. Because the signals of the identified base stations are receiving by the mobile station 18 with a significantly smaller SNR than at least one other than the one-way link signal, the increase in the error rate of the mobile station will be small in relation to the reduction in transmission power for the complete system. Although the identified base stations do not continue to transmit the traffic channel, the signal processing resources within those base stations will remain allocated and ready to begin transmitting the traffic channel with the request of the system controller 10. Also, these base stations preferably continue to process the transmitted backlink signal of the mobile station 18. As the communication continues, the mobile station 18 continues to check the relative strength of the received pilots from the base stations in the active set. When the state of a pilot changes, for example when a pilot is received above the threshold r, the mobile station 18 generates another message in the bit field indicating the change in state. The mobile station 18 also generates a bit-field message when the pilot channel with the best SNR changes. The system controller 10 receives the message from the bit field and instructs any base station in the active set, for which the state has changed, to start transmitting the traffic channel for that mobile station, or to not continue the transmission of the traffic channel, as the case may be. Each base station responds by transmitting the following data box via the traffic channel if the instruction can start the transmission, or by not transmitting the following data box if the instruction was to continue or not the transmission of the traffic channel. In the alternate embodiments of the invention, the mobile station 18 periodically generates messages from the bit field, for example once each frame. By keeping the allocated resources within each base station to transmit the traffic channel, the traffic channel can be activated and deactivated quickly in response to rapidly changing conditions. In yet another embodiment of the invention, the system controller 10 includes a gain adjustment field in each data frame sent to the base station. The gain adjustment field indicates the transmitted transmitted power at which the frame will be transmitted from the base station. When the system controller 10 receives a vector indicating that the pilot channel of a particular base station is received less than the threshold? R below the strongest pilot channel, the gain adjustment in the next frame directed to that subscriber is reduced. . Subsequent tables can be further reduced as more vectors indicate that the pilot channel of that base station remains with the threshold ? r below the strongest driver. The control system 10 can also perform a more advanced analysis of the received bit vectors, to better determine the stability of the medium in which the mobile station is operating. In particular, the control system 10 can verify the speed at which a particular pilot channel changes, of being above and below the threshold? R. If the rate of change exceeds a predetermined threshold, the control system 10 will determine that the mobile station is in a fading or otherwise unstable means, and therefore that the signal of each base station in the flexible transfer, must be transmitted. continually. When such a determination is made, the control system 10 instructs all the base stations of the active set to continue transmitting the forward link traffic channel, even though the pilot channels are with the threshold? R below the received pilot channel. . FIGURE 6B shows an alternative data structure for a bit vector message of the pilot quality, transmitted from the mobile station to the system controller 10 via the base station. That alternative modality is similar in structure to the data structure defined in FIGURE 6A, although it only includes 5 bits to identify the six members of the active set. Only five bits are used because the identity of the sixth (ie, the base station provides the strongest signal-to-noise ratio), is identified by the first three bits of the pilot-quality bit vector message (it is say, I1-3). Uniquely identifying the strongest signal in the first three bits of the pilot quality bit vector message, each of the other members of the active set is sequentially identified by the subsequent bits in the quality bit vector message of the pilot, with an implicit understanding that there is not a bit that identifies the position of the strongest base station. FIGURE 6C shows an additional, alternate pilot quality bit vector message format where the first three I? _3 bits are used to uniquely identify the strongest pilots of the base stations in the active set, the following three bits J1-3 identify the strongest seconds, and the third set of three bits K? _3, identify the third strongest pilot of the members of the active set. Thus, each of the three strongest pilots of the members in the active set are uniquely identified. An extension of this modality would be to add three additional bits for each of the fourth or fifth or sixth strongest pilot of the members of the active set, thus identifying them in a unique way. An additional modality would be to add an additional bit to the message, to indicate the relative strength of pilots at finer quantization levels, rather than simply above and below the threshold? R. Still another additional modality would be to include all Ec / I0 values for each pilot. Thus, for a system with six possible pilots in the active set, the Ec / Io would be included for each possible active set. It should also be clear that sending the Ec / Io of the major pilot in the active set, and then the relative Ec / I0 values, relates to the larger pilot, is another possible modality. Although each of the modalities in FIGURE 6A through FIGURE 6C define alternative ways to report the relative measured powers, preferably on a frame-by-frame basis, combinations of the alternative methods are also possible. For example, the first six bits of the measured power message can be used to uniquely identify the first two strongest pilots of the base station members, while the next three bits are used to identify the relative positions of the three next strongest pilots (ie, for a set of five members). An additional alternative method would be to have only a single base station, which transmits the mobile station. In this case, only the three-bit vector message (ie, 11-3) needs to be sent from the mobile station to the base station. An alternative arrangement is to have the base station of multiple carriers transmit through a single antenna at a time. In this case, a single bit is needed to specify which antenna can be used. Clearly, this can be used in combination with the methods described above. When communicating over known fast or slow fade channels, an alternative way to determine the threshold? R is used to more effectively overcome the effects of fading. In contrast to the preferred embodiment, the? R is based on the pilot that has the highest average SNR on the frame, in the present mode, the minimum value of the maximum pilot on the frame is used to determine? R. Thus, if at least the strongest pilots are subjected to fading, adjusting the threshold? R to the minimum of the strongest pilot on the frame, will allow more pilots above the threshold? R. As a result, a greater amount of diversity gain can be achieved by combining the signals of more base stations, thus adding / more independent or at least semi-independent trajectories. More particularly, in a medium with rapid fading, the previously described use of the minimum value for the strongest driver on the table is expected to work adequately for a scenario with rapid fading, where the durations of the fading are relatively small, with respect to the length of the frame. However, for channels with slow fading, the performance of the rake receiver, and the mobile station, is not greater than in the case of a medium with fast fading, mainly because an interleaver is used in the reception process, which it does not provide as much benefit as would ordinarily be, when the fades have a duration, which is less than the length of the duration of the interleaving. However, slow fades where the duration of the fade is greater than the interleaved interval, an Eb / No greater is required, in order to provide an acceptable communication quality in the mobile station. In addition, the duration of a frame for averaging over the respective pilot forces is insufficiently short to determine whether the respective communication channels are subject to fading or not. Accordingly, in this alternative embodiment, each of the respective base stations implements a filter, which integrates and normalizes each of the bits Uk (FIGURES 6A and 6B), into the vector message of bits. If individual bits of the Uk bits vasculate, that is, change their states at least once, then this vasculation indicates that the channel between the respective base station and the mobile station is subject to a slow fading. Consequently, the system performance of the CDMA system will be improved if the base station subjected to slow fading continues to transmit on the outbound traffic channel. This observed vasculation can also be used as an indicator in the system controller, to indicate whether the mobile station should be placed in a flexible transfer region. For example, if the bit field representing the pilot strength for a given base station is almost always close to zero, or always at zero, then the respective base station should indicate that the pilot is, in fact, much weaker than the strongest pilot, and the base station that produces the weakest pilot, should not be included in the active set, since it practically does not add any beneficial value to the performance of the mobile station. It should also be clear that the mobile station can effectively verify the vasculation operation, and then transmit the message to the base station, only when it wants to change to the base stations transmitting to the mobile station. Another alternative allows the signaling and switching processes to take place more quickly. In this case, the mobile station indicates to the base station directly during a fading, when the signal from the base station becomes stronger or weaker than the signals from one or more of the other base stations. The base station responds by not transmitting or transmitting the following frame. In this case, the switching can be quite fast because the base station can respond more quickly than the controller of the base station, allowing a first frame to be sent from a base station, and the next frame to be sent from another base station. base. This works at relatively average fade speeds. When signaling and switching are even faster, switching may occur during a frame. In this case, the base station must receive the data to be transmitted during the frame. In one embodiment, the base stations encode, intercalate and further process the data for transmission. The output data stream is enabled or disabled based on the feedback from the mobile station. As an alternative to the threshold method for determining which pilots to identify in the bit vector of the pilot quality, a second method of "digit assignment" is described herein. In the mobile station, the mobile station calculates the Ec / Io of the received pilot, from each base station in the active set. If the mobile station does not have a digit of its diversity receiver assigned to the base station, the Ec / Io for that pilot is set to 0. If the mobile station has a digit of the diversity receiver assigned to a given base station, the mobile station determines the average Ec / Io over the previous 20 milliseconds (preferably, although, alternatively, higher or lower average times could be used), and reports that value. The period of 20 milliseconds corresponds to a CDMA length table. The mobile station then identifies the major pilot having the value of Ec / Io greater, and assigns an index to Am. For all other pilots in the active set, the mobile station adjusts to respective bit values in the vector message of bits a 1, if the value of Ec / Io for that pilot is within? r of the value of Ec / Io for the maximum pilot. If the receiver has only N digits, then N is less than 6, but no more than N pilots are reported in the bit vector message. Because the digits can be assigned to either a direct signal path or an image path (eg, a multipath image), the digit assignment methods prevent "too many" base stations from reporting as having signals which are usable by the mobile station. For example, if a diversity receiver has three digits, and only two base stations produce the three signals with the quality plus the three signals with the highest quality (ie, the direct paths for each base station and an image signal) , then there is no need for a third base station to transmit to the mobile station, because the receiver does not have enough digits to receive it. On the other hand, if the pilot of the third base station periodically exceeds one of the other three signals, the mobile station may, however, report to the following stations as being above the desired threshold, because there are a number of cases wherein the diversity receiver would combine the signal of the third base station. Thus, in one embodiment of the invention, the pilot SNR for a base station is reported based on the digit with the highest SNR received from the base station. 'FIGURE 7 is a flow chart showing a preferred method for adjusting the power assignments of the forward channel. The process starts in step YES, wherein a mobile station measures the pilot strengths (signal qualities) of all the pilots within the active set of the mobile station. The process then proceeds to step S3, wherein the mobile station, based on the measured pilot forces, measured in step SI, generates a threshold signal? R. The signal? R is generated based on the pilot that has the highest SNR as measured in step SI. The process then proceeds to step S5, at which each of the respective pilots, pilotj, is compared to the signal? R to determine if the respective pilot is greater than or equal to? R. This comparison step is preferably performed over the duration of a frame period of 20 milliseconds, and ends at the end of a frame period, although other sampling intervals taken at other points within a frame or in multiple frames is consistent with this modality. If the respective pilot is greater than or equal to? R, a bit in the vector message of bits (see for example, FIGURES 6A-6C), indicates that the pilot! respective is greater than the threshold? r. If, however, in step S5 it is determined that the pilot is not greater than or equal to? R, a bit in the vector message of bits is adjusted to indicate that the respective pilot is less than or equal to? R (of preference by setting the bit to "0"). After the bit vector of the pilot quality is formed in step S7 or step S9, the process proceeds to step Sil, wherein the mobile station sends the vector message of bits to the base stations and the active set of the mobile station. At this time, the mobile station adjusts a synchronization circuit, which is used in the mobile station as an indicator for the mobile station to determine when the mobile station should adjust its digits based on the anticipation of the mobile station of the mobile controller. system 10, which adjusts the power in the forward traffic channel in response to the previous vector vector message of the mobile station. By adjusting the synchronization circuit (which is easily achieved by the mobile station counting 20 frames of 20 milliseconds in a row), the mobile station knows when the change in transmissions of the forward traffic channel will occur. After step Sil, the process then proceeds to step S13, where the base stations receive and transmit the bit vector of the pilot quality to the system controller. After step S13, the process proceeds to step S15, wherein a selector in the system controller processes the message of the bit vector, and produces a control message, sent to each 'one of the respective base stations in the active set of the mobile station, which controls which of the base stations in the active set of the mobile station should transmit a respective code channel to the mobile station. By controlling the transmissions of each of the base stations in the active set of the mobile station, the total power radiated from the base stations in the active set of the mobile station is reduced. The process then proceeds to step S17, where after the clock reaches a time threshold, the mobile station sets the digits in its corresponding diversity receiver, with the base stations identified as being equal to or greater than the signal? r as determined in steps S7 and S9. By adjusting the digits, the mobile station combines the energy received only from those base stations in the active set of the mobile station, which in fact, are transmitting in their respective code channels. After step S17, the process is repeated, wherein the mobile station continues to verify the respective pilot strengths, for each of the base stations in the active set of the mobile station. Because the mobile station generated in the particular bit vector message, and the response of each base station in the bit vector message is based on a predetermined algorithm, the time in which each base station changes the allocation of the forward link , it is known by the mobile station. Thus, the mobile station can suitably combine the signals of only those base stations, which are transmitting at that moment. This is advantageous because combining the signals of the base stations that are not transmitting to the particular mobile station would cause unnecessary noise introduced by the reception processing, which has a negative impact on the result. This will result in a loss of performance, a higher Eb / No requirement, and a loss in capacity. Similarly, if the mobile station does not combine the signals, which were transmitted to the mobile station, and which were received with sufficient force, there would be a loss in capacity. In one embodiment of the invention, the mobile station compensates for transmission errors in the reception of the bit vector received by each base station, first attempting to demodulate the received round frame, assuming that the message was correctly received and processed by the base station . In most cases, the mobile station will demodulate the frame correctly. However, if the frame has an error, then the mobile station may attempt to use the set of base stations that were transmitting to the mobile station before it sent the most recent vector bit message. Thus, if the base station does not receive the most recent bit vector message, then the mobile station would attempt to demodulate the frame again using the set of base stations, which was previously used. This requires that the mobile station keep the received signal from the different set of base stations in a buffer. Next, the mobile station would use the data in this buffer when an error occurred. This error correlation processing is illustrated by the optional steps S19 and S21 of FIGURE 7, as indicated by the dotted line to step S19. FIGURE 8 is a flowchart of an alternative method for changing the power allocation of the forward traffic channel for the base stations in the active set of the mobile station. The process begins at step S32, where the mobile station measures the respective pilot strengths of each of the base stations in the active set of the mobile station. Next, in step S34, the mobile station generates the threshold signal? R, based on the measured pilot forces. Next, in step S36, the mobile station compares both direct (directi) and multipath signals, for each of the base stations and compares the direct and / or multipath signals to determine whether either the direct or multipath signals are greater than or equal to? r. If a direct or multi-path image is greater than or equal to? R, the process proceeds to step S38, where the diversity receiver assigns a digit or digits to the direct and / or multipath signals, which are larger than ? r, as determined in step S36. Subsequently, the process proceeds to step S42. However, if in step S36 it is determined that none of the direct or multi-path signals of a base station is greater than or equal to? R, the process proceeds to step S40, where none of the digits of the rake receiver and the combiner's circle are assigned to that particular base station. The process then proceeds to step S42. It should be noted that the? R in Figure 8 is different than that in FIGURE 7. In FIGURE 7,? R was used to determine whether to report a pilot or not.; FIGURE 8 is used to determine the assignment of a digit to the rake demodulator. As such, the? R in FIGURE 8 will typically be smaller than that in FIGURE 7.

In step S42, the mobile station sends a vector message of bits to the base station and to the active set, indicating the digit assignment made in the mobile station in the direct and multipath signals. If the direct or multi-path signals are greater than ρr, the mobile station formats the bit vector message, which indicates that at least the direct or multi-path image is greater than or equal to r r. The process proceeds to step S44, wherein the base station transmits the vector message of bits to the selector in the system controller, so that the system controller is informed of the session of the digit used in the mobile station, and Thus, you can adjust the potential assignment of the outgoing traffic channel of which base stations are transmitting to the mobile station, for each of the base stations in the active set of the mobile station, The process then proceeds to step S46 , wherein the selector sends a control message to the base stations in the active set of the mobile station indicating which of the base stations are transmitted over their respective code channels, corresponding to the digit assignment set by the mobile station. The base stations transmit the control message to the mobile station, so that the mobile station is notified that the base stations e that they have been informed of the allocation of the power of the outbound traffic channel of the system controller. The process then proceeds to step S48, wherein the mobile station adjusts the digits in the diversity receiver, in response to the control message generated by the system controller. It should be noted that both the control message sent from the mobile station to the base station or from the base station to the mobile station may have an error. A technique similar to that described in conjunction with FIGURE 7 can be used. In this case, if the mobile station does not receive the control message or the base station or if it receives a frame with an error, it can demodulate the previous set of base stations, which were transmitting to the mobile station. In an alternative method, to change the power allocation of the forward traffic channel, the passages SI 'to S15 are the same as those shown in the preferred method of FIGURE 7, although the base station also transmits to the mobile station a indication of which of the base stations are in fact, transmitting in their respective forward traffic channels. Thus, in this alternate mode, the system controller, not the mobile station, controls which of the base stations transmit to the mobile station. This invention has been described in terms of adjusting a threshold? R relative to the strongest pilot, as described in the text and in FIGURES 5A and 5B. Many alternative metrics can be used. In particular, one that sets bit U1 to "1" only when the pilot in sufficient enough the total Ec / I0, can also be used. This technique is described in a co-pending United States patent application entitled "Method and Apparatus for Performing a Flexible Transfer in a Wireless Communications System", no. of series 08 / 790,497, assigned to the beneficiary of the present invention, and incorporated herein by reference. The invention has been described in terms of transmitting a full outbound link from a set of base stations and a mobile station. A system and method for conducting a high-speed data link, using a supplementary and a fundamental channel, is described in the co-pending US patent application no. series 08 / 798,949, entitled "Reduction of Transmission Power for a High-Speed CDMA Link in a Flexible Transfer", and in the United States patent application, co-pending, no. series 08 / 784,281, entitled "High Speed Data Supplementary Channel for a CDMA Telecommunications System", both assigned to the beneficiary of the present invention, and incorporated herein by reference. In this high-speed data link system, the outbound link is divided into a fundamental channel and an additional one. The fundamental channel is transmitted continuously from all the base stations in the active set. The supplementary channel is transmitted from the same base stations as the fundamental channel or a subset thereof. The invention described herein may be applied to either the fundamental channel, the supplementary channel or both. FIGURE 9 is a spectrum diagram of a forward link with extended spectrum with multiple carriers, and a broadband extended spectrum link with a single carrier. Although it is not shown completely to scale, for the process with multiple carriers, the propagation bandwidth for each carrier is shown as 1.25 MHz, and for the broadband process with a single carrier, the propagation bandwidth is 3.6864 MHz. The multi-carrier method has several advantages, including allowing each carrier to be transmitted from a differently configured antenna, which, in turn, provides a unique fading pattern for each carrier, decreasing the probability that the three carriers vanish simultaneously, and therefore, that the communications are interrupted. FIGURE 10 is a block diagram of a multi-carrier transmission system, configured in accordance with one embodiment of the invention. The input data is encoded and drilled convolutionally, by a conventional encoder 100, and the coded symbols are repeated by the symbol repeater 102, to add additional redundancy. The block interleaver 104 inserts the repeated symbols into the blocks in time intervals of 20 ms and the interleaved symbols are mixed via XOR 106, with a long decimated code, generated by a long code generator 108 and a decimator 110, in response to a mask of the user's long code. The mixed symbols are demultiplexed by the demux 112 in three symbol streams, which are each transmitted on a respective carrier signal. For each carrier signal, the respective symbol streams are plotted by QPSK by the QPSK tracers 114. The QPSK symbols are each modulated with the same Walsh channel code by the Walsh code modulators 116 and the resulting Walsh chips are further modulated with a propagation code in PNj phase, and a propagation code in quadrature phase PNQ by the propagators 118. PNS and PNQ are preferably the same for each carrier. The resulting propagated symbols are then each converted upwardly to a single carrier frequency, preferably as shown in FIG. 9, and transmitted. Figure 10 shows the modulation by the same Walsh channel code for each carrier, however, the Walsh channel code may be different. FIGURE 11 is a block diagram of a portion of a receiver system employed by a mobile unit for processing a signal with multiple carriers, when configured in accordance with one embodiment of the invention. The downconverted RF energy is filtered with bandpass at 5 MHZ, by bandpass filter 200, and sampled by A / D 202 at a speed of 8x1.2288 MHz. Within filter bank 204, two 1.25MHZ portions of the samples are digitally converted to a baseband by the numerically controlled 1.2MHz (NCO) oscillator, or optionally by an NCO of 1.25MHz and an NCO of 2.5MHz, and all three Sample sets are filtered by low pass to a bandwidth of 1.25 MHz. This low pass filter can be the filter matched to the receiver or a part of it. The resulting sets of the filtered data with low pass are passed to the rake receiver 210, which demodulates and combines the various cases of multiple trajectories of the transmitted signal. The resulting flexible decision data, combined, is passed to a de-interleaver, for de-interleaving and subsequent decoding. Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. Therefore, it should be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (42)

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. A method for adjusting the potential assignment of the forward traffic channel in a communication system, characterized in that it comprises the steps of: measuring in a mobile station, the qualities of the respective signal of pilots transmitted respectively by a plurality of base stations in an active set of the mobile station; compare the respective signal qualities of the pilots with a standard; report a message to a system controller indicating which of the pilots in the mobile station equals or exceeds the standard; and 'adjust the power allocation of the forward traffic channel based on the message.

2. The method according to claim 1, characterized in that the step of comparing comprises: generating a threshold signal as the standard, based on at least one of the pilots having the highest measured signal quality, over a range of predetermined time; and comparing each of the respective signal qualities of the pilots, with the threshold signal.

3. . The method according to claim 2, characterized in that the step of reporting comprises the steps of: generating a vector list of bits in values with a predetermined order, representative of the qualities of the respective signal of the pilots; and include in the vectorial list of bits an index that identifies which of the pilots has the highest measured signal quality.

4. The method according to claim 3, characterized in that the step of reporting comprises reporting the bit vector to the system controller, at least once every CDMA IS-95 protocol frame.

5. The method according to claim 3, characterized in that the step of reporting comprises reporting the bit vector to the system controller, in at least one of multiple frames and fractions of the CDMA IS-95 protocol frame.

6. The method according to claim 3, characterized in that the communication system comprises a CDMA communication system IS-95 and the communication step comprises communicating the bit vector either periodically or not.

The method according to claim 2, characterized in that: the step of measuring comprises measuring the respective signal to interference ratios of the pilots; and the step of generating generally comprises a threshold signal based on at least one of the respective higher signal to interference ratios for the pilots.

8. The method according to claim 7, characterized in that the step of generating comprises subtracting from the greater of the signal to interference ratios, a predetermined level to produce the threshold signal.

The method according to claim 8, characterized in that the greater of the respective signal to interference ratios, has a minimum, and the step of comparing comprises comparing each of the qualities of the respective signal of the pilots with a minimum of the highest signal-to-interference ratio of the pilots.

10. The method according to claim 3, characterized in that the step of listing, further comprises the steps of: receiving a transfer address message, which identifies the base stations in the active set of the mobile station, in a default order; arrange the respective data fields of the bit vector to correspond to the order; and placing the respective values in the respective data fields, indicating that if the respective pilots exceed the threshold signal.

The method according to claim 10, characterized in that: the step of receiving comprises receiving a set of. direct and multipath signals that correspond to the signals of the pilot, the set of direct signals and with received multiple trajectories, comprises a subset of N direct and with multiple trajectories received, each one exhibiting a signal to interference ratio that is greater than each of a subset of signals that are not in the subset of the N direct signals and with multiple trajectories received; and the placing step places the respective values indicative of the respective ones of the pilots exceeding the threshold signal in the respective data fields, only if the respective ones of the pilots correspond to at least one of the subset of N direct signals and with trajectories multiple received.

The method according to claim 10, characterized in that it further comprises the step of adding to the message a data field of the active set, in which at least one of a current active set, a past active set and a set future assets, are identifiable.

The method according to claim 1, characterized in that the step of measuring comprises measuring the signal qualities of the pilots, transmitted respectively by at least one sector of a respective one of the plurality of base stations in the active set.

14. The method according to claim 1, characterized in that the step of adjusting comprises: forming a command to control the allocation of the power of the forward traffic channel, which indicates which of the base stations will transmit code channels. respective to the mobile station and which will not transmit respective code channels to the mobile station; and communicating the command to control the allocation of the power of the forward traffic channel to the plurality of base stations in the active set.

The method according to claim 1, characterized in that it further comprises the steps of: initiating a timing mechanism in the mobile station when the message is initially reported from the mobile station; and observing when a delay time has been reached, the delay time corresponds to a difference in time between when the message is initially reported, from the mobile station and when the power of the forward traffic channel has been adjusted.

16. The method according to claim 15, characterized in that it also comprises the step of changing the digit assignment of at least one digit of a diversity receiver in the mobile station, the digit assignment corresponds to which of the pilots that were reported in the message in the reporting step, equals or exceeds the standard.

17. The method according to claim 14, characterized in that the step of forming forms the command to control the allocation of the power of the forward traffic channel, to indicate that no more than N of the base stations will transmit respective code channels to the mobile station, where N corresponds to a number of digits in a diversity receiver in the mobile station.

18. The method according to claim 1, characterized in that: the step of comparing comprises determining whether at least one digit of a diversity receiver has been assigned to a signal of the code channel of a base station; and the reporting step comprises reporting which of the base stations provides a signal from the respective channel that has been assigned to at least one digit.

19. The method according to claim 18, characterized in that the step of reporting comprises the step of generating a listing of the vector of bits in values in a predetermined order, representative of the qualities of the respective signal of the pilots.

The method according to claim 19, characterized in that the step of reporting comprises including in the bit vector, an index identifying one of the plurality of base stations having at least two digits assigned to them.

The method according to claim 19, characterized in that the step of reporting comprises reporting the bit vector to the system controller at least once every frame of a CDMA IS-95 protocol.

22. The method according to claim 19, characterized in that the step of reporting comprises reporting the bit vector to the system controller in at least one of multiple frames and fractions of a CDMA IS-95 protocol frame.

23. The method according to claim 19, characterized in that the communication system comprises a CDMA communication system IS-95 and the communication step, comprises communicating the bit vector either periodically or not.

24. The method according to claim 18, characterized in that the step of generating, further comprises the steps of: receiving a transfer address message, which identifies the plurality of base stations in the active set of the station mobile, in a predetermined order; arranging the respective data fields in the message for each of the plurality of base stations to correspond to the predetermined order; and placing the respective values in the respective data fields, indicative of whether at least one digit of the diversity receiver has been designated respectively to the plurality of the base stations.

The method according to claim 24, characterized in that it further comprises the step of adding to the message a data field of the active set, in which at least one of a current active set, a past active set and a set future assets, are identifiable.

26. The method according to claim 1, characterized in that the pilots are transmitted on a plurality of carrier signals.

27. The method according to claim 26, characterized in that the plurality of carrier signals are transmitted from a corresponding plurality of antennas configured differently.

28. A communication system, characterized in that it comprises: a plurality of base stations, which transmit respective pilots and respective code channels comprising a forward traffic channel; a system controller communicatively connected to the plurality of base stations; a mobile station, which has a plurality of base stations assigned to an active set thereof, comprising, a diversity receiver, which measures the qualities of the respective signal of the pilots; a processor, which produces a standard of signal quality and prepares a message that indicates which of the signal qualities of the pilots equals or exceeds the standard; a mobile transmitter, which transmits a message to the system controller, either directly or via the plurality of base stations; and the system controller adjusts a transmitted power level of the forward traffic channel, in response to receipt of the message.

29. The communication system according to claim 28, characterized in that the mobile station processor comprises: a mechanism for generating a threshold that generates a threshold signal as the standard, based on at least one of the pilots that has the quality of the measured signal greater, over a predetermined time interval; and a comparison mechanism that compares the respective signal qualities of the pilots with the threshold signal.

30. The communication system according to claim 29, characterized in that the processor of the mobile station comprises a mechanism for formatting the message, which generates in the message a bit vector comprising a list of values representative of whether the respective signal qualities of the pilots, equal or surpass a threshold signal and an index, which identifies which of the pilots has the highest measured signal quality. f

31. The communication system according to claim 29, characterized in that the mobile transmitter transmits a bit vector at least once every frame of a CDMA IS-95 protocol.

32. The communication system according to claim 30, characterized in that the mobile transmitter transmits the bit vector in at least one of multiple frames and fractions of a CDMA IS-95 protocol frame.

33. The communications system according to claim 28, characterized in that the diversity receiver comprises: a pilot receiver, which measures the qualities of the respective signal of the pilots, and N digits, each of which receives the minus one of the code channels via at least one of a direct path and a trajectory with multiple paths of a base station.

34. The communication system according to claim 33, characterized in that the processor comprises: an allocation mechanism, which assigns the N digits to a subset of N of at least one of the code channels exhibiting higher signal to interference ratio than all other signals corresponding to the code channels; and a mechanism for formatting the message, which provides a list and an index in the message, the list includes values representative of whether the respective one of the pilots corresponds. to the N subset of at least one of the code channels, and the index identifies which of the pilots has the highest measured signal quality.

35. The communication system according to claim 28, characterized in that the plurality of base stations, each comprising a plurality of sectors that transmits the respective pilots and the respective code channels in different geographically selected regions.

36. The communication system according to claim 28, characterized in that the system controller comprises: a control processor that determines which of the signal qualities of the pilots indicated in the message as equaling or exceeding the quality standard of the signal, corresponds to which subset of the plurality of base stations; and a mechanism for formatting the control signal, which forms a control signal, which is communicated to the plurality of base stations, to control the power allocation of the forward traffic channel, controlling the power levels of the channel of code, of the subset of the plurality of base stations, as determined by the control processor.

37. The communication system according to claim 30, characterized in that the mechanism for formatting the message comprises: a receiving mechanism that receives the transfer address message, which identifies in a predetermined order the plurality of base stations in the active set; and an arrangement mechanism that arranges the respective data fields for each of the plurality of base stations corresponding to the order and places the values in the respective data fields corresponding to the order, the values indicative of whether the qualities of the Pilot signal equals or exceeds the threshold signal.

38. An apparatus for changing the power allocation of a forward traffic channel, characterized in that it comprises: a mobile unit, comprising, means for measuring the qualities of the respective signal of the signals transmitted by a plurality of base stations, means for generating a signal quality standard based on the signal qualities measured by the measurement means, means for generating a bit vector that lists the base stations that have measured signal qualities not less than the standard , each of the base stations in an active set of the mobile unit, a transmitter that transmits the bit vector; and means for adjusting the power allocation of the forward channel of the plurality of base stations, based on the plurality of base stations identified in the bit vector.

39. The apparatus according to claim 38, characterized in that the processor comprises: a mechanism that generates a threshold that generates a threshold signal as the standard of signal quality, based on at least one of the pilots that has the quality of the measured signal greater, over a predetermined time interval; and a comparison mechanism that compares the qualities of the respective signal of the pilots with the threshold signal.

40. The apparatus according to claim 38, characterized in that: the means for measuring comprises a diversity receiver having n digits; The processor comprises a mechanism for determining, which determines whether at least one digit of the diversity receiver has been assigned to a code channel signal of a base station; and the means for generating a bit vector, lists the base stations that provide respective code channel signals, which have been assigned to at least one digit.

41. The apparatus according to claim 38, characterized in that the signals are comprised of a plurality of different carrier signals.

42. The apparatus according to claim 41, characterized in that the plurality of different carrier signals are transmitted from a corresponding plurality of antennas configured differently.