HK1076669A - A method and an apparatus for improving stability and capacity in cdma medium data rate systems - Google Patents

Description

Method and apparatus for improving stability and capacity in CDMA medium data rate system

Background

I. Field of the invention

The present invention relates to communications. More particularly, the present invention relates to a method and apparatus for managing radio frequency power of a medium data rate (MDA) in a CDMA communication system in order to improve the capacity and stability of the system.

Description of the related Art

The use of Code Division Multiple Access (CDMA) modulation techniques is one of several techniques for facilitating communications in which a large number of system users are present. While other techniques such as Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), and AM modulation schemes such as Amplitude Companded Single Sideband (ACSSB) are known, CDMA has significant advantages over these other techniques. The use of CDMA techniques in MULTIPLE access communication SYSTEMs is disclosed in U.S. patent No. 4901307 entitled SPREAD SPECTRUM acquisition SYSTEM USING SATELLITE technology OR TERRESTRIAL REPEATERS, which is assigned to the assignee of the present invention and incorporated herein by reference. The use of CDMA techniques IN multiple access communication SYSTEMs is further disclosed IN U.S. patent No. 5103459 entitled SYSTEM AND METHOD FOR generating a signal level IN a CDMA CELLULAR TELEPHONE SYSTEM, which is assigned to the assignee of the present invention and is incorporated herein by reference. The CDMA System may be designed to conform to "TIA/EIA/IS-95 Mobile Station-base Compatibility Standard for Dual-Mode Wideband Spread Spectrum cellular System", hereinafter referred to as the IS-95 Standard.

A CDMA system is a spread spectrum communication system. The benefits of spread spectrum communications are well known in the art and can be understood by reference to the above citations. CDMA provides a form of frequency diversity by its inherent nature of wideband signals by spreading the signal energy over a wide bandwidth. Thus, frequency selective fading affects only a small portion of the CDMA signal bandwidth. Spatial or path diversity is obtained by providing multiple signal paths through a synchronous link to a mobile user or remote station through two or more base stations. In addition, path diversity can be obtained by utilizing a multipath environment in spread spectrum processing by allowing signals having different propagation delays to be received and processed, respectively, upon arrival. Examples of path diversity are described IN U.S. patent No. 5101501 entitled METHOD AND SYSTEM FOR PROVIDING a software IN communication IN a CDMA CELLULAR TELEPHONE SYSTEM and U.S. patent No. 5109390 entitled DIVERSITY RECEIVER IN A CDMA CELLULAR TELEPHONE SYSTEM, which are assigned to the assignee of the present invention and incorporated herein by reference.

Code division multiple access communication systems have been standardized in the American Telecommunications industry Association TIA/EIA/IS-95-B STANDARD entitled "Mobile STATION synchronization FOR Dual-MODE Wireless communication System," which IS incorporated herein by reference and IS referred to hereinafter as IS-95-B.

EIA/TIA IS-95-A with TSB-74 and ANSI J-STD-008(IS-95-A) introduced a standardized CDMA communication network that carries basic rate voice and data traffic. EIA/TIA IS-95-B (IS-95-B) adds this basic capability with support for MDR by allowing a base station to communicate with a mobile station using up to 8 parallel forward and 8 parallel reverse links. A description of a set of procedures IS used in packet data transmission in IS-95-B systems. The telecommunications industry Association temporary Standard TIA/EIA/IS-707-A entitled "DATA SERVICE OPTIONS FOR SPREAD SPECTRUM SYSTEMS" IS hereinafter referred to as IS-707.

In TIA/EIA/IS-707-A.8 entitled "DATA SERVICE OPTIONS FOR SPREAD SPECTRUMSYSTEMS: RADIO Link PROTOCOL TYPE 2 "describes a RADIO Link PROTOCOL (RLP), hereinafter referred to as RLP2 and incorporated by reference herein. RLP2 combines the error control protocol with the frame retransmission process at the IS-95-B group frame level. RLP is a class of error control protocols known as NAK-based ARQ protocols, which are well known in the art. IS-707 RLP facilitates the transmission of a byte stream, rather than a series of voice frames, over an IS-95-B communication system.

Several protocol layers are typically located above the RLP layer. For example, IP datagrams are typically converted to a point-to-point protocol (PPP) byte stream before being submitted as a byte stream to the RLP protocol layer. The data flows transmitted by the RLP are referred to as "featureless data flows" because the RLP layer ignores the protocols and framing of the higher protocol layers.

RLP was originally designed to meet the need for sending large datagrams over IS-95 channels with wireline reliability. For example, if 500 bytes of IP datagrams are sent in only 20 byte each IS-95-B frame, the IP datagrams may fill 25 consecutive IS-95 frames. Without a certain error control layer type, all 25 such RLP frames need to be received error-free to make IP datagrams available to higher protocol layers. On IS-95 channels with 1% frame error rate, the effective error rate for IP datagram delivery IS (1- (0.99)25) or 22%. This is a very high error rate compared to most networks used to carry internet protocol traffic. Designing RLP as a link layer protocol reduces the error rate of IP traffic compared to the typical error rate of a typical 10Base2 ethernet channel.

The international telecommunications union has recently required the submission of proposed methods for providing high-rate data as well as high-quality voice services over wireless communication channels. The first such proposal was published by the telecommunications industry association under the title "the cdma2000 ITU-R RTT cancer subscription". The telecommunications industry association has recently developed a cdma2000 recommendation as the provisional standard TIA/EIA/IS-2000 and IS referred to hereinafter as cdma 2000. A second such proposal is published by The European Telecommunications Standards Institute (ETSI), entitled "The ETSI UMTS Terrestrial Radio Access (UTRA) ITU-R RTT radio Transmission, also known as" wideband CDMA "and referred to hereinafter as W-CDMA. A third proposal has been made by U.S. TG 8/1 entitled "The UWC-136 conference sub", hereinafter referred to as EDGE. The contents of these recommendations are public records and are well known in the art.

RLP2 IS designed for IS-95-B. In a system titled "DATA SERVICE OPTIONS FOR streaming media SYSTEMS: a new RLP designed for cdma2000, hereinafter referred to as RLP3E, IS described in TIA/EIA/IS-707-A-1.10 of RADIO LINK PROTOCOL TYPE 3 ", and IS incorporated herein by reference.

The IS-95-a voice system relies on high performance Markov voice statistics for a large number of uncorrelated users per carrier per cell, as well as Radio Frequency (RF) capacity and RF stability. The large number of uncorrelated high performance users results in forward link RF transmit power distributions that are predictably steady and have lognormal distributions. Without this forward link RF power predictability, forward link power control and mobile assisted handoff may be unstable.

Unfortunately, packet data traffic does not perform so well, and data traffic typically arrives in bursts, resulting in a relatively long maximum rate transmission period followed by a relatively long minimum rate transmission period. These effects become more pronounced with the advent of medium data rates in IS-95-B. Multiple links of medium rate users are correlated. Unlike non-coherent voice links, the data link and power control together transition between a maximum rate and a minimum rate. This makes the forward link RF transmit power distribution certain to be non-stationary and non-lognormal, and thus potentially unstable.

There IS therefore a need for addressing network stability and capacity issues when using MDR without changing the IS-95-B air interface standard.

Summary of The Invention

The present invention IS directed to novel methods and apparatus for achieving optimal capacity and stability in IS-95-B based media data rate systems. According to the invention, a constant fraction of the total available transmit power of the base station is allocated to each user. Data is transmitted to each user at the allocated transmission power and the data rate is changed according to the channel condition of the user.

In accordance with another aspect of the present invention, a constant portion of the total available transmit power of the base station is allocated as the data transmit power on the primary forward channel and the transmit power on the supplemental forward link. Each user is assigned a fundamental channel. The data transmission rate to the users is varied by assigning supplemental forward channels according to the RF conditions of the communication link and the data rate required by each user.

In another aspect of the invention, a base station transmitting at a fixed power is allowed to adjust the fixed power in steps to enable varying long term data throughput.

Brief Description of Drawings

The features, objects, and advantages of the present invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings in which like reference characters identify correspondingly throughout and wherein:

fig. 1 is a bar chart illustrating power allocation to users.

Fig. 2 is a bar chart illustrating power allocation to base stations.

Fig. 3 illustrates an exemplary embodiment of a terrestrial wireless communication system.

Fig. 4 illustrates an exemplary embodiment of a base station, according to one embodiment.

Fig. 5A-D illustrate an exemplary embodiment of a flow diagram according to one embodiment.

Detailed description of the preferred embodiments

Fig. 1 illustrates an embodiment of the present invention using data transmission at a constant power level per user and variable data rate depending on user RF link conditions. This is possible because packet data users do not require a strict grade of service (GoS) like voice services that require guaranteed minimum bandwidth and maximum delay. According to one embodiment, a fixed total power is allocated for a packet data call in addition to one or more forward code channels. FIG. 1a shows a medium data rate P_TMDRThe total power allocated to the transmission is shown. The power satisfies equation 1:

wherein P is_TUiIs the total power allocated to user i and N is the number of users.

FIG. 1b shows a block diagram of a basic forward channel P that can be used_FUCan be used for M supplemental forward channels P_SUTotal power P between_TMDRThe allocation of (c). The allocation is made in a manner that satisfies the following equation:

wherein P is_TUiIs the total power of user i, and M_iIs the supplemental forward channel number for user i.

Initiating a call by a user on a primary forward channel at a sufficiently low data rate to ensure that primary forward channel power control varies by no more than an allocated user power P_FU. Then according to the basic channel power P_FUSetting supplemental forward channel P_SUThe power level of (c). The maximum number of supplemental channels that can be used is then determined using equation (2). Since the forward channel power control is only used for the fundamental forward channel, equation (2) and the maximum number of supplemental channels are used to adjust the supplemental forward channel P_SUOf (2) isA level. If no data is transmitted on the supplemental forward channel (either because there is insufficient power or because all data can be transmitted on the fundamental forward channel), then the empty supplemental forward channel is transmitted with sufficient power to ensure equation (2) is satisfied. If the required transmitted data rate needs to exceed the total user power P_TUThen a data rate low enough to keep the required power below the total power is transmitted. Low data rates are achieved by first using a less supplemental forward channel and then using a less than full rate fundamental forward channel. The Radio Link Protocol (RLP) sequence number allows the mobile station to determine whether the erasure of the supplemental forward channel is a result of an erased packet or an unsent packet.

Transmitting with "constant user power" reduces base station transmit power variations due to power control and data activity. However, this method is not effective because it requires the user to transmit waste power when there is no data to transmit. The greater the difference between the minimum and maximum user data rates, the greater the potential inefficiency. Therefore, in another embodiment of the present invention, the base station considers the forward link medium data rate power P_TMDRAnd (4) time sharing. The base station assigns a unique basic forward channel to each medium rate packet data user. The base station then assigns each medium rate packet data user from 0 to a maximum number of assignable supplemental forward channels. In one embodiment, the maximum number of supplemental forward channels allocable per user is 7. The supplemental forward channel may be simultaneously allocated to multiple users. The base station schedules the use of the supplemental forward channel by covering each frame of the supplemental forward channel with a user-specific long code. Therefore, all users that do not use a particular long code cannot decode the supplemental channel frames of other users. Fig. 2 illustrates the power allocation in this case. FIG. 2a shows the data rate P as the transmission medium_TMDRBut the total power allocated. Equation 3 that this power satisfies:

wherein P is_TUiA value is assigned to the total power of user i and N is the number of users.

Fig. 2b shows the transmission of the medium data rate P between the supplemental and fundamental forward channels_TMDRThe total power allocation of (c). Since N users are assumed, the power P allocated to the fundamental forward channel_TFIncluding the power P of the fundamental forward channel available to each user_FUThe sum of (a) and (b) such that:

this is illustrated by the right column of the histogram of fig. 2 b. The left column of the histogram of FIG. 2b illustrates the power P allocated for the supplemental forward channel_TS. Note that there is no supplemental forward channel CH between the N users, based on the principle of adjusting the data rate to use the available power_iPredetermined allocated power P_TS. According to the required M supplementary forward messagesChannel CH_iAvailable to all users. Thus, if an increased data rate is required for a particular user, the power P of the forward channel is replenished_TSAdditional channels are allocated to the users. However, the user cannot use more supplemental forward channels than are allocated to the user. Conversely, when a reduced data rate is desired for a particular user, the user is instructed to release its supplemental forward channel for use by another user. The allocation and de-allocation rates must be selected so as not to interfere with power control. The power allocation among users must satisfy equation (5):

P_TMDR＝P_TF+P_TS (5)

transmitting at "constant user power" and "common supplemental forward channel" reduces base station transmit power variations due to power control per user and data activity per user. However, it cannot eliminate short term variations in transmit power due to variations in data activity and long term variations in transmit power due to variations in data requirements. According to another embodiment of the present invention, the base station transmits at a "fixed" power level by transmitting on an unused forward channel a power equal to the difference between the power required for data transmission and the "fixed" power level, thus eliminating variations in transmit power due to variations in data activity. Because users may have different frame offsets, each power control group must adjust the additional power transmitted. For explanation of power control see the IS-95 standard mentioned above. Variations due to data requirements are reduced by adjusting the "fixed" power level. In this way, the base station reduces the amount of "fixed" power allocated for data services as the data needed decreases. In one embodiment, the variation of the "fixed" power gradually prevents interference with the power control method. In one embodiment of the invention, the "fixed" transmit power level is controlled by an outer power control loop. The outer power control loop adjusts the fixed transmit power level so that the fixed level does not saturate frequently. The additional margin in this adjustment beyond the exact "fixed" amount of power is to account for new users arriving at the base station.

Fig. 3 illustrates an exemplary embodiment of a terrestrial wireless communication system, represented by a Base Station (BS)302 and a Remote Station (RS)304, that communicate over a forward link 306 carrying information from the BS 302 to the RS 304 and a reverse link 308 carrying information from the RS 304 to the BS 302. Each link 306, 308 includes a primary forward channel and at least one supplemental forward channel. RS 304 may be any number of wireless communication devices including, but not limited to, cellular telephones, wireless local loop telephones, personal digital assistants, and wireless modems.

Fig. 4 shows an exemplary embodiment of a transmitting station. Information to be transmitted is generated by a data source 402 and provided to a memory 404. The memory 404 acts as a buffer to prevent data loss when the data source 402 provides more data than can be sent. Data from memory 404 is provided to demultiplexer 406 which demultiplexes the data according to signal 408 provided by control circuit 410. The demultiplexed data is provided to channel elements 412a through 412h which divide the data, CRC encode the data, and insert code tail bits as needed by the system.

Channel elements 412a through 412h then convolutionally encode the data, CRC parity codes, and code tail bits, interleave the encoded data, scramble the interleaved data with a user long Pseudo Noise (PN) sequence, and cover the scrambled data with a Walsh sequence. Channel elements 412a through 412h then provide the covered data to spreaders 414a through 414h, respectively, which use the short in-phase Pseudo Noise (PN)_I) And quadrature phase Pseudo Noise (PN)_Q) The sequence spreads the data. For more details reference IS made to the IS-95 standard mentioned above. The spread data is then filtered at filters 416a through 416h and the filtered data is provided to gain stages 418a through 418h, which scale the data in response to signals 420a through 420h from control circuit 410. Control circuit 410 may be any device capable of performing the function of generating signals 420a through 420 h. Such devices include, for example, programmable logic arrays, application specific circuits, digital signal processors, and the like. The scaled data are accumulated in accumulator 422 and provided to modulator 424, which uses in-phase and quadrature-phaseThe sinusoid of the bits upconverts the data. The upconverted signal is provided to a gain stage 426 for scaling. The scaled signal is filtered and amplified at block 430. Signals are transmitted on forward channel 306 (if the transmitting station is a BS) or reverse channel 308 (if the transmitting station is an RS) via antenna 432.

A feedback signal from a receiving station (not shown) is received by an antenna 434 and provided to a receiver 436. The receiver filters, amplifies, downconverts, quadrature demodulates, and digitizes the received signal. The digitized signal is provided to a demodulator 438 which uses short PN_IAnd PN_QThe sequence despreads the data and decovers the despread data with a user long PN sequence. The descrambled (or demodulated) data is provided to decoder 440, which performs the inverse of the encoding performed in channel element 412. The decoded data is provided to a data receiver 442 and control circuitry 410.

FIG. 5 is a flow diagram illustrating a process for implementing stability and capacity control according to one embodiment.

The process begins at step 500 where a sending station is initialized to a standby state to provide service to a user. The initialization procedure may include an initial allocation of the total transmit power of the transmitting station. According to one embodiment of the present invention, the total transmit power is constantly allocated between voice services and data services. In another embodiment, the allocation of total transmit power is dynamically varied between voice services and data services. For the purpose of illustrating power allocation, it is assumed that the transmitting station supports several voice calls and several data users.

In step 502, the transmitting station receives a data service request, which is passed to step 504. Step 504 represents an exemplary embodiment of a transmission scheduling method. Step 5042 determines whether the request should be granted.

If the request is not granted, the request is passed to step 5044 for further transmit scheduling processing. The reschedule request is passed to step 506.

If the request is granted at step 5042, processing continues at step 506.

Step 506 asks whether the available power is sufficient to support additional users. If the response is negative, the flow chart proceeds to step 508.

In the variable power allocation embodiment, the operation of step 508 is described in fig. 5 a. In step 50802, a query is made as to whether to reallocate power from voice service to data service. If the response is positive, the reassignment is performed at step 50804 and the flow continues at step 506 of FIG. 5. Returning to fig. 5a, if the response is negative, it is further queried in step 50806 whether the maximum transmit power of the BS is reached. If the response is in the affirmative, no power is available and the request is passed to the process of step 50404. If the response is negative, the BS allocates part of the total transmit power to the data service in step 50808, and the flow continues in step 506 of fig. 5.

In the embodiment of constant power allocation, the operation of step 508 is described in fig. 5 b. Since the power allocated for the voice service is not allowed to be shared, it is queried whether the maximum transmission power of the BS is reached at step 50810. If the response is in the affirmative, then no power is available and the request is passed to the processing of step 5044 of FIG. 5. Returning to fig. 5b, if the response is negative, the BS allocates a portion of the total transmit power to the data service at step 50812 and the flow continues at step 506 of fig. 5.

When the response to power sufficiency is positive in step 504, the flow chart proceeds to step 510.

Fig. 5c illustrates the operation of step 510 according to an embodiment of the present invention without incorporating the supplemental forward channel sharing concept. As described with reference to fig. 1a, 1b, the total user power P is allocated to the data service users in step 51002_TUWhich includes a basic forward channel power P_FUAnd supplemental forward channel power P_SU. In step 51004, a call is initiated on the fundamental forward channel at a data rate low enough to ensure that the fundamental forward channel forward power control does not vary by more than the allocated power P_FU. Step 51006 compares the requested data rate with the requested data rateThe transmitted data rates are compared. If the requested data rate is less than or equal to the transmitted data rate, the power level P of the null supplemental forward channel is adjusted in step 51008_SUTo ensure total power P_TUIs correct, i.e. equation (1) is satisfied. When the requested data rate is higher than the transmitted data rate, an additional supplemental forward channel is utilized in step 51010. Adjusting power level P of supplemental forward channel_SUTo ensure total power P_TUIs correct, i.e. equation (1) is satisfied.

Fig. 5d illustrates the operation of step 510 according to an embodiment of the present invention incorporating the supplemental forward channel sharing concept. As described with reference to fig. 2, a basic forward channel power P is allocated to a data service user in step 51012_FU. In step 51014, a call is initiated on the fundamental forward channel at a data rate low enough to ensure that the fundamental forward channel forward power control does not vary by more than the allocated power P_FU. Step 51016 compares the requested data rate with the sent data rate. If the requested data rate is less than or equal to the transmitted data rate, the power level P of the supplemental forward channel is adjusted in step 51018_SUTo ensure total power P_TUIs correct, i.e. equation (4) is satisfied. When the requested data rate is higher than the transmitted data rate, additional supplemental forward channels are allocated from the pool of supplemental forward channels in step 51020. Adjusting power level P of supplemental forward channel_SUTo ensure total power P_TUIs correct, i.e. equation (4) is satisfied.

The previous description of the preferred embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without the use of the inventive faculty. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (28)

1. A method of transmitting variable rate data in a communication system, comprising

Allocating medium data rate transmit power among users of said communication system; and

transmitting data to at least one of the users over the radio frequency link at the allocated transmit power.

2. The method of claim 1, wherein said medium rate data transmit power is a constant fraction of a total transmit power.

3. The method of claim 1, wherein said medium rate data transmit power is a variable fraction of total transmit power.

4. A method according to claim 3, characterized in that said variable share is determined according to the data rate requirements to be transmitted.

5. The method of claim 1, wherein allocating the medium data rate transmit power comprises:

allocating the medium data rate transmission power between a first power pool for allocation to a basic forward channel and a second power pool for allocation to a supplemental forward channel; and

at least a basic forward channel is assigned to each of the users.

6. The method of claim 5, wherein allocating at least one primary forward channel comprises:

allocating a first power required to support the basic forward channel from the first power pool;

determining a number of supplemental channels based on the requested data rate and the available power from the second power pool; and

allocating a second power required to support the number of supplemental channels from the second power pool;

7. the method of claim 6, wherein determining the number of supplemental channels comprises:

initiating communication between a transmitting station and a receiving station over the fundamental forward channel at a data rate supportable by the first power;

determining a supplemental forward channel power from the first power; and

determining a number of the supplemental forward channels based on the determined supplemental forward channel power, the second power pool, and the requested rate.

8. The method of claim 7, wherein determining a number of supplemental channels is further performed based on a maximum number of supplemental forward channels allocated to said user of said primary forward channel.

9. The method of claim 1 wherein allocating medium rate data transmit power comprises:

allocating an equal portion of said total medium data rate transmit power to each of said users;

allocating the equal portion between a first power for a primary forward channel and a second power pool for allocation to a supplemental forward channel; and

allocating the primary forward channel and at least one supplemental forward channel for each of the users.

10. The method of claim 9, wherein assigning at least one of said supplemental forward channels comprises:

determining a number of supplemental forward channels based on the requested data rate and the available power in the second power pool;

allocating all power from the second power pool among the number of supplemental channels; and

allocating all power from the second power pool to a supplemental forward channel when the number equals 0.

11. The method of claim 10 wherein determining said number of supplemental forward channels comprises the steps of:

initiating communication between a transmitting station and a receiving station over the fundamental forward channel at a data rate supportable by the first power;

determining a minimum supplemental forward channel power from the first power;

determining a maximum number of supplemental forward channels based on the minimum supplemental forward channel power and the second power pool;

determining the number of supplemental forward channels based on the requested data rate and the maximum number of supplemental forward channels.

12. The method of claim 11, wherein determining a maximum number of supplemental channels is further performed based on a maximum number of supplemental forward channels assigned to said user of said fundamental forward channel.

13. The method of claim 1, wherein transmitting data comprises adjusting a rate of said data based on said at least one user channel condition.

14. The method of claim 1, wherein the step of transmitting data comprises the steps of:

adjusting a basic forward channel power according to a channel condition of the at least one user; and

adjusting supplemental forward channel power such that a sum of the base forward channel power and supplemental forward channel power equals the allocated transmit power.

15. An apparatus for transmitting variable rate data in a communication system, comprising

Providing a data source of data to be transmitted;

a transmitter for transmitting the data; and

a control processor communicatively coupled to the transmitter and configured to:

allocating medium rate data transmission power among users of said communication system; and

causing said transmitter to transmit said data to at least one of said users over a radio frequency link at said allocated transmit power.

16. The apparatus of claim 15 wherein said medium rate data transmit power is a constant fraction of the total transmit power.

17. The apparatus of claim 15 wherein said medium rate data transmit power is a variable fraction of total transmit power.

18. The apparatus of claim 17, wherein the control processor is further configured to perform the operation of varying the variable fraction as needed based on a data rate to be transmitted.

19. The apparatus of claim 15, wherein the control processor is configured to allocate the medium data rate transmit power by:

allocating the medium data rate transmission power between a first power pool for allocation to a basic forward channel and a second power pool for allocation to a supplemental forward channel; and

at least a basic forward channel is assigned to each of the users.

20. The apparatus of claim 19, wherein the control processor is configured to allocate the at least one fundamental forward channel by:

allocating a first power required to support the basic forward channel from the first power pool;

determining a number of supplemental channels based on the requested data rate and the available power from the second power pool; and

allocating a second power required to support the number of supplemental channels from the second power pool;

21. the apparatus of claim 20 wherein the control processor is configured to determine the number of supplemental channels by:

initiating communication between a transmitting station and a receiving station over the fundamental forward channel at a data rate supportable by the first power;

determining a supplemental forward channel power from the first power; and

determining a number of the supplemental forward channels based on the determined supplemental forward channel power, the second power pool, and the requested rate.

22. The apparatus of claim 21 wherein the control processor is configured to determine the number of supplemental channels based on a maximum number of supplemental forward channels assigned to said user of said primary forward channel.

23. The apparatus of claim 15 wherein the control processor is configured to allocate the medium data rate transmit power by:

allocating an equal portion of said total medium data rate transmit power to each of said users;

allocating the equal portion between a first power for a primary forward channel and a second power for allocation to a supplemental forward channel; and

allocating the primary forward channel and at least one supplemental forward channel for each of the users.

24. The apparatus of claim 23 wherein the control processor is configured to perform the operation of assigning at least one of said supplemental forward channels by:

determining a number of supplemental forward channels based on the requested data rate and the available power in the second power pool.

Allocating all power from the second power pool among the number of supplemental channels; and

allocating all power from the second power pool to a supplemental forward channel when the number equals 0.

25. The apparatus of claim 24, wherein the control processor is configured to determine the number of supplemental forward channels by:

initiating communication between a transmitting station and a receiving station over the fundamental forward channel at a data rate supportable by the first power;

determining a minimum supplemental forward channel power from the first power;

determining a maximum number of supplemental forward channels based on the minimum supplemental forward channel power and the second power pool;

determining the number of supplemental forward channels based on the requested data rate and the maximum number of supplemental forward channels.

26. The apparatus of claim 11 wherein the control processor is configured to determine the number of supplemental channels based on a maximum number of supplemental forward channels assigned to said user of said primary forward channel.

27. The apparatus of claim 15, wherein the control processor is configured to perform operations for transmitting data comprising adjusting a rate of said data based on said at least one user channel condition.

28. The method of claim 15, wherein the control processor is configured to perform the operation of transmitting data by:

adjusting a basic forward channel power according to a channel condition of the at least one user; and

adjusting supplemental forward channel power such that a sum of the base forward channel power and supplemental forward channel power equals the allocated transmit power.