Patent Publication Number: US-8116805-B2

Title: Uplink scheduling for OFDM systems

Description:
BACKGROUND 
     I. Field 
     The following description relates generally to wireless communications, and more particularly to uplink scheduling in a wireless communication system. 
     II. Background 
     Wireless communication systems are widely deployed to provide various types of communication; for instance, voice and/or data may be provided via such wireless communication systems. A typical wireless communication system, or network, can provide multiple users access to one or more shared resources. For instance, a system may use a variety of multiple access techniques such as Frequency Division Multiplexing (FDM), Time Division Multiplexing (TDM), Code Division Multiplexing (CDM), Orthogonal Frequency Division Multiplexing, (OFDM), and others. 
     Common wireless communication systems employ one or more base stations that provide a coverage area. A typical base station can transmit multiple data streams for broadcast, multicast and/or unicast services, wherein a data stream may be a stream of data that can be of independent reception interest to a mobile device. A mobile device within the coverage area of such base station can be employed to receive one, more than one, or all the data streams carried by the composite stream. Likewise, a mobile device can transmit data to the base station or another mobile device. 
     Generally, wireless multiple-access communication systems may simultaneously support communication for multiple mobile devices. Each mobile device may communicate with one or more base stations via transmissions on forward and reverse links. The forward link (or downlink) refers to the communication link from base stations to mobile devices, and the reverse link (or uplink) refers to the communication link from mobile devices to base stations. 
     Wireless Communication systems (e.g., OFDM systems) oftentimes schedule downlink and uplink transmissions. As an example, base stations commonly assign channels, times, frequencies, and so forth for mobile devices to utilize for communicating over the uplink. Conventional techniques, however, oftentimes fail to consider fairness in connection with uplink scheduling. Moreover, common uplink scheduling typically fails to leverage multi-user diversity. 
     SUMMARY 
     The following presents a simplified summary of one or more embodiments in order to provide a basic understanding of such embodiments. This summary is not an extensive overview of all contemplated embodiments, and is intended to neither identify key or critical elements of all embodiments nor delineate the scope of any or all embodiments. Its sole purpose is to present some concepts of one or more embodiments in a simplified form as a prelude to the more detailed description that is presented later. 
     In accordance with one or more embodiments and corresponding disclosure thereof, various aspects are described in connection with facilitating scheduling of transmissions upon an uplink traffic channel in Orthogonal Frequency Division Multiplexing (OFDM) environments. Uplink scheduling may include user selection and rate selection. Further, user selection may be based on a token mechanism that provides control over fairness of allocation to disparate users. Moreover, rate selection may be based upon considerations of uplink interference mitigation. 
     According to related aspects, a method that facilitates uplink scheduling in an Orthogonal Frequency Division Multiplexing (OFDM) environment is described herein. The method may comprise selecting a user to transmit on an uplink traffic channel during a time-frequency slot as a function of a token value. Further, the method may include determining a rate for transmission on the uplink channel by the user. Moreover, the method may comprise sending an assignment to the user. 
     Another aspect relates to a wireless communications apparatus. The wireless communications apparatus may include a memory that retains data signaled over an uplink and instructions related to determining a token metric and a multi-user diversity metric based upon the signaled data, choosing a mobile device to transmit on an uplink traffic channel during a time-frequency slot based upon the token metric and the multi-user diversity metric, controlling a rate for uplink transmission based upon the signaled data, and transmitting an assignment to the mobile device on a downlink. Further, the communications apparatus may comprise a processor, coupled to the memory, configured to execute the instructions retained in the memory. 
     Yet another aspect relates to a wireless communications apparatus that schedules uplink transmission on traffic channels. The wireless communications apparatus may include means for selecting a mobile device for uplink transmission based upon a token metric and a multi-user diversity metric; means for identifying a rate for the uplink transmission based upon interference mitigation; and means for transmitting an assignment to the mobile device, the assignment includes data related to the rate. 
     Still another aspect relates to a machine-readable medium having stored thereon machine-executable instructions for receiving information signaled on an uplink, identifying a token metric and a multi-user diversity metric based upon the received information, and assigning a time-frequency slot for uplink transmission on a traffic channel to a mobile device as a function of a combination of the token metric and the multi-user diversity metric. The machine-readable medium may further have stored thereon machine-executable instructions for selecting, a code rate for the mobile device to employ for the uplink transmission and sending an assignment that indicates the time-frequency slot, the traffic channel, and the code rate via a downlink to the mobile device. 
     In accordance with another aspect, an apparatus in a wireless communications system may include a processor, wherein the processor may be configured to schedule a user for uplink transmission on a traffic channel based upon a token. Further, the processor may be configured to determine a rate for the uplink transmission that mitigates interference. Moreover, the processor may be configured to transmit an assignment to the user that indicates the rate. 
     According to a further aspect, a method that facilitates signaling information over an uplink in connection with obtaining a scheduled assignment for transmission over the uplink is described herein. The method may comprise signaling information including a Beacon ratio report, a traffic priority, and a maximum power available to a base station over an uplink. Further, the method may include obtaining an uplink assignment including a rate from the base station, the assignment being generated at least in part upon the signaled information. Moreover, the method may comprise transmitting traffic on the uplink by employing the assignment. 
     Another aspect relates to a wireless communications apparatus. The wireless communications apparatus may include a memory that retains instructions for measuring an interference cost, sending the measured interference cost over an uplink, and receiving data allocating a time, channel and rate for uplink traffic transmission based upon a token metric that is determined by the base station as a function of the interference cost. Further, the wireless communications apparatus may include a processor, coupled to the memory, configured to execute the instructions retained in the memory. 
     Still another aspect relates to a wireless communications apparatus that signals a measured interference cost to a base station in connection with obtaining an uplink assignment. The wireless communications apparatus may include means for measuring an interference cost; means for transmitting the measured interference cost on an uplink; means for receiving an assignment allocated as a function of a token value, the token value being determined based upon the interference cost; and means for transmitting on an uplink traffic channel based upon the assignment, the assignment controls a rate associated with transmission. 
     Yet another aspect relates to a machine-readable medium having stored thereon machine-executable instructions for signaling interference data measured at a mobile device to a base station, obtaining an assignment of an uplink traffic channel, time-frequency slot, and rate, the base station selecting the mobile device for the assignment in view of a token value based at least in part upon the interference data, and employing the assignment to transmit on the uplink traffic channel. 
     In accordance with another aspect, an apparatus in a wireless communication system may include a processor, wherein the processor may be configured to receive information related to an allotted uplink channel, time-frequency slot, and rate at a mobile device, where the uplink traffic channel is assigned to the mobile device as a function of a token metric and a multi-user diversity metric. Further, the processor may be configured to transmit traffic on the allotted uplink channel during the time-frequency slot and at the rate. 
     To the accomplishment of the foregoing and related ends, the one or more embodiments comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative aspects of the one or more embodiments. These aspects are indicative, however, of but a few of the various ways in which the principles of various embodiments may be employed and the described embodiments are intended to include all such aspects and their equivalents. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an illustration of an example wireless communication system in accordance with various aspects set forth herein. 
         FIG. 2  is an illustration of an example system that signals information on an uplink to enable selecting users and/or rates for uplink scheduling. 
         FIG. 3  is an illustration of an example system that schedules uplink transmissions in a wireless communication environment. 
         FIG. 4  is an illustration of an example methodology that facilitates uplink scheduling in an OFDM environment. 
         FIG. 5  is an illustration of an example methodology that facilitates scheduling uplink transmissions by utilizing information obtained from mobile devices. 
         FIG. 6  is an illustration of an example methodology that facilitates signaling information over an uplink in connection with obtaining a scheduled assignment for transmission over the uplink. 
         FIG. 7  is an illustration of an example communication system implemented in accordance with various aspects including multiple cells. 
         FIG. 8  is an illustration of an example base station in accordance with various aspects. 
         FIG. 9  is an illustration of an example wireless terminal (e.g., mobile device, end node, . . . ) implemented in accordance with various aspects described herein. 
         FIG. 10  is an illustration of an example system that schedules uplink transmission on traffic channels. 
         FIG. 11  is an illustration of an example system that signals a measured interference cost to a base station in connection with obtaining an uplink assignment. 
     
    
    
     DETAILED DESCRIPTION 
     Various embodiments are now described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of one or more embodiments. It may be evident, however, that such embodiment(s) may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing one or more embodiments. 
     As used in this application, the terms “component,” “module,” “system,” and the like are intended to refer to a computer-related entity, either hardware, firmware, a combination of hardware and software, software, or software in execution. For example, a component may be, but is not limited to being, a process running on a processor, a processor, an object, an executable, a thread of execution, a program, and/or a computer. By way of illustration, both an application running on a computing device and the computing device can be a component. One or more components can reside within a process and/or thread of execution and a component may be localized on one computer and/or distributed between two or more computers. In addition, these components can execute from various computer readable media having various data structures stored thereon. The components may communicate by way of local and/or remote processes such as in accordance with a signal having one or more data packets (e.g., data from one component interacting with another component in a local system, distributed system, and/or across a network such as the Internet with other systems by way of the signal). 
     Furthermore, various embodiments are described herein in connection with a mobile device. A mobile device may refer to a device providing voice and/or data connectivity to a user. A mobile device may be connected to a computing device such as a laptop computer or desktop computer, or it may be a self contained device such as a personal digital assistant (PDA). A mobile device can also be called a system, a wireless terminal, a subscriber unit, a subscriber station, mobile station, mobile, remote station, access point, remote terminal, access terminal, user terminal, user agent, user device, or user equipment. A mobile device may be a subscriber station, wireless device, cellular telephone, PCS telephone, cordless telephone, a Session Initiation Protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device having wireless connection capability, or other processing device connected to a wireless modem. 
     A base station (e.g., access point) may refer to a device in an access network that communicates over the air-interface, through one or more sectors, with mobile devices. The base station may act as a router between the mobile device and the rest of the access network, which may include an IP network, by converting received air-interface frames to IP packets. The base station also coordinates management of attributes for the air interface. 
     Moreover, various aspects or features described herein, may be implemented as a method, apparatus, or article of manufacture using standard programming and/or engineering techniques. The term “article of manufacture” as used herein is intended to encompass a computer program accessible from any computer-readable device, carrier, or media. For example, computer-readable media can include but are not limited to magnetic storage devices (e.g., hard disk, floppy disk, magnetic strips, etc.), optical disks (e.g., compact disk (CD), digital versatile disk (DVD), etc.), smart cards, and flash memory devices (e.g., EPROM, card, stick, key drive, etc.). Additionally, various storage media described herein can represent one or more devices and/or other machine-readable media for storing information. The term “machine-readable medium” can include, without being limited to, wireless channels and various other media capable of storing, containing, and/or carrying instructions) and/or data. 
     Referring now to  FIG. 1 , a wireless communication system  100  is illustrated in accordance with various embodiments presented herein. System  100  can comprise a base station  102  that receives, transmits, repeats, etc., wireless communication signals to mobile devices (e.g., mobile device 1  104 , mobile device 2  106 , mobile device N  108 , where N may be substantially any integer). Further, it is contemplated that system  100  may include a plurality of base stations similar to base station  102 . Although three mobile devices  104 - 108  are depicted, it is to be appreciated that system  100  may include substantially any number of mobile devices. Base station  102  can comprise a transmitter chain and a receiver chain, each of which can in turn comprise a plurality of components associated with signal transmission and reception (e.g., processors, modulators, multiplexers, demodulators, demultiplexers, antennas, etc.), as will be appreciated by one skilled in the art. Base station  102  may be a fixed station and/or mobile. Mobile device 1  104  (and similarly mobile device 2  106  and mobile device N  108 ) can be, for example, a cellular phone, a smart phone, a laptop, a handheld communication device, a handheld computing device, a satellite radio, a global positioning system, a PDA, and/or any other suitable device for communicating over wireless communication system  100 . Also, mobile devices  104 - 108  may be fixed or mobile. 
     Each mobile device  104 - 108  may communicate with base station  102  (and/or disparate base station(s)) on a downlink and/or an uplink channel at any given moment. The downlink refers to the communication link from base station  102  to mobile device  104 - 108 , and the uplink channel refers to the communication link from mobile device  104 - 108  to base station  102 . Base station  102  may further communicate with other base station(s) and/or any disparate devices (e.g., servers) (not shown) that may perform functions such as, for example, authentication and authorization of mobile device  104 - 108 , accounting, billing, and so on. 
     Base station  102  may include an uplink scheduler  110  that schedules uplink transmissions from mobile devices  104 - 108  to base station  102  (e.g., in an Orthogonal Frequency Division Multiplexing (OFDM) system). By way of illustration, an uplink may include a plurality of traffic channels (e.g., uplink traffic channels (ULTCHs)) at any number of time-frequency slots. Uplink scheduler  110  may assign a particular mobile device (e.g., mobile device 1  104 ) to a specified traffic channel and time-frequency slot, and a disparate mobile device (e.g., mobile device 2  106 ) to a differing traffic channel and/or time-frequency slot. Additionally, uplink scheduler  110  may select various parameters associated with assigned uplink transmissions. For example, assignments may provide information related to time, frequency, power, code rate, modulation, and the like that may be employed by mobile devices  104 - 108  in connection with assigned uplink transmissions. Further, uplink scheduler  110  may transmit uplink assignments over the downlink to respective mobile devices  104 - 108  (e.g., on a downlink traffic control channel (DLTCCH)). 
     Uplink scheduler  110  may include a user selector  112  and a rate selector  114 . A user is any mobile device that has a connection with the Base Station and can be signaled an assignment on the downlink for uplink traffic. Since system  100  may include a plurality of mobile devices  104 - 108  (e.g., each with associated user(s)), user selector  112  enables choosing a particular mobile device (e.g., mobile device 2  106 ) from amongst the set of mobile devices  104 - 108  to assign to an uplink traffic channel during a time-frequency slot. For instance, user selector  112  may control fairness and take advantage of multi-user diversity in connection with allocating uplink access to mobile devices  104 - 108 . According to an example, user selector  112  may leverage a token mechanism to control fairness. Pursuant to this example, a number of tokens may be distributed to differing users; the user selector  112  may assign a mobile based upon a current value of the tokens (e.g., which may be measured by various factors). Further, the user selector  112  may update the value of the tokens during substantially every slot based upon one or more of these factors. User selector  112  may evaluate the various factors related to mobile devices  104 - 108  in connection with allotting time-frequency slots (e.g., traffic channels) for transmission on uplink traffic channels (e.g., based on the updated token values); the factors corresponding to each of the mobile devices  104 - 108  may be, for example, an interference cost (e.g., Beacon ratio report, path loss report, . . . ), a traffic priority, a maximum available power, an amount of time since a mobile was previously assigned, a quality of service (QoS) class, and the like. It is contemplated that any number of these factors may be utilized in any manner to yield the token values. 
     Moreover, upon user selector  112  apportioning an uplink traffic channel and time-frequency slot to a particular mobile device (e.g., mobile device 2  106 ), rate selector  114  may assign a rate (e.g., code rate) to be employed for the uplink transmission on the traffic channel during the time-frequency slot. Rate selector  114  may control the selected user (e.g., selected mobile device, mobile device 2  106 , . . . ) to utilize rates that may optimize, without instabilizing, system  100 . For example, rate selector  114  may determine the rate for uplink transmission based upon an interference cost (e.g., Beacon ratio report, path loss report, . . . ) associated with the selected mobile device (e.g., mobile device 2  106 ), a maximum available power of the selected mobile device, and/or QoS data. According to another example, rate selector  114  may determine a power (e.g., nominal power) to be utilized for the uplink transmission on the traffic channel during the time-frequency slot (e.g., based upon the interference cost, maximum available power of the selected mobile device, QoS data, . . . ). 
     Now turning to  FIG. 2 , illustrated is a system  200  that signals information on an uplink to enable selecting users and/or rates for uplink scheduling. System  200  includes base station  102  that communicates with a mobile device  202  (e.g., one of mobile devices  104 - 108 ) and/or any number of disparate mobile devices (not shown). Base station may include uplink scheduler  110 , which may further comprise user selector  112  and rate selector  114  that allocate access to uplink traffic channels and control rates utilized upon such uplink traffic channels, respectively. 
     Mobile device  202  may include an interference analyzer  204  that may evaluate an interference cost at mobile device  202  (e.g., by employing substantially any technique). For instance, the interference cost determined by interference analyzer  204  may be a Beacon ratio report, a path loss report, and so forth. Further, interference analyzer  204  may signal the interference cost measured at mobile device  202  to base station  102  on the uplink. 
     By way of example, mobile device  202  may be connected to base station  102 , and signals transmitted between base station  102  and mobile device  202  may be subject to a first path gain, G 1 . Further, signals transferred between a disparate base station (not shown) and mobile device  202  may be subject to a second path gain, G 2 . According to an illustration, interference analyzer  204  may determine the interference cost, α, by evaluating 
             α   =         G   2       G   1       .           
For instance, if α is close to zero, mobile device  202  may be in close proximity to base station  102  and relatively far from the disparate base station, and if α is close to one, the distance to base station  102  from mobile device  202  may be more similar to the distance to the disparate base station from mobile device  202 .
 
     Pursuant to another illustration, any number of base stations may be employed in system  200 ; thus, interference analyzer  204  may calculate the interference cost as 
               α   =         ∑   i     ⁢           ⁢     G   i         G   0         ,     where   ⁢           ⁢       ∑   i     ⁢           ⁢     G   i               
may be the sum of path gains (e.g., corresponding to disparate base stations (not shown)) and G 0  may be the path gain between base station  102  and mobile device  202 . In accordance with a further example, base station  102  and disparate base station(s) (not shown) may transmit respective loading factors, s; therefore, interference analyzer  204  may determine the interference cost as a function of loading factors, such as, by evaluating
 
             α   =           ∑   i     ⁢           ⁢       s   i     ⁢     G   i             s   0     ⁢     G   0         .           
By way of another example, Beacon signals transmitted by base station  102  and disparate base stations may be obtained by mobile device  202 , and interference analyzer  204  may generate a Beacon ratio report. It is contemplated that any manner of determining the interference cost known by both base station  102  and mobile device  202  may be utilized in connection with the claimed subject matter. Further, interference analyzer  204  (and/or mobile device  202 ) may signal the measured interference cost to base station  102  for utilization by uplink scheduler  110 .
 
     Additionally, mobile device  202  may include a traffic signaler  206  and a power signaler  208 . Traffic signaler  206  may send traffic priority information to base station  102 . For example, the traffic priority information may be associated with an importance of data to be transmitted by mobile device  202  over the uplink, a type of such data, an amount of the data, delay experienced by that data thus far in the queue, and so forth. Further, power signaler  208  sends information related to a maximum available power that may be employed by mobile device  202  for transmission (e.g., over the uplink) to base station  102 . 
     Base station  102  may farther include memory  210  that may retain data, which may be utilized by user selector  112  and/or rate selector  114 . Memory  210  may store data generated by base station  102 , received from mobile device  202  (and/or disparate mobile devices), obtained from a server, and so forth. For example, memory  210  may retain interference data  212 , traffic priority data  214 , power data  216 , time data  218 , and/or QoS data  220 , each of which may include data associated with a plurality of mobile devices (e.g., including mobile device  202 ). Interference data  212  may be the interference cost information obtained from interference analyzer  204 . Moreover, traffic priority data  214  and power data  216  may be similarly received from mobile device  202  via traffic signaler  206  and power signaler  208 , respectively. Additionally, time data  218  may be information related to a time since a last assignment for mobile device(s) (e.g., mobile device  202 ). QoS data  220  may be quality of service (QoS) classes associated with users (e.g., mobile devices); for example, QoS classes may be defined by an amount paid for service (e.g., higher subscription fee collected for a QoS class that provides a higher level of access to uplink channels). 
     According to an example, user selector  112  may employ interference data  212 , traffic priority data  214 , power data  216 , time data  218 , and QoS data  220  in connection with assigning uplink traffic channels to mobile devices (e.g., mobile device  202 ). Pursuant to another example, fate selector  114  may utilize interference data  212 , power data  216 , and QoS data  220  to determine a code rate to be employed by the assigned mobile devices. Further to this example, a higher QoS class as noted in QoS data  220  can lead to higher rate allocation by rate selector  114  for substantially similar interference data  212  if power data  216  specifies that the rate is supportable. It is to be appreciated, however, that the claimed subject matter is not limited to the foregoing examples. Thereafter, base station  102  may transfer uplink assignments (e.g., that may include the selected rates) to mobile device  202  and/or disparate mobile devices. 
     With reference to  FIG. 3 , illustrated is a system  300  that schedules uplink transmissions in a wireless communication environment. System  300  includes base station  102  that receives mobile related data (e.g., interference costs, traffic priority reports, maximum power availability reports, . . . ) signaled over an uplink. Base station  102  may include uplink scheduler  110  that generates assignments by employing user selector  112  and rate selector  114 , and assignments may be sent on a downlink. Further, in response to the assignments, base station  102  may obtain uplink traffic (e.g., at assigned times, frequencies, code rates, modulation schemes, . . . ). 
     User selector  112  enables uplink scheduling with user selection based on user metrics where the user metrics may be based on token allocation (e.g., resulting in a token metric) and a multitude of factors (e.g., QoS, time since last assignment, interference report, traffic priority, power, . . . ). User selector  112  may further comprise a token manager  302  and a multi-user evaluator  304 . Both token manager  302  and multi-user evaluator  304  may contribute to part of a user metric for user selection. At each time-frequency slot, users may be chosen by user selector  112  based upon 
                 i   *     =     arg   ⁢           ⁢       max     i   ∈   U       ⁢     Metric   i           ,         
where U is a set of schedulable users at a particular time-frequency slot and Metric i  is a total metric of a user i. The total metric of a user is evaluated on a per user basis by user selector  112  as Metric=TokenMetric+UserSpecificMetric. For example, the total metric may be computed as follows: Metric=TokenMetric+MudMetric. Token manager  302  may yield TokenMetric and multi-user evaluator  304  may generate MudMetric (e.g., which may be a metric exploiting multi-user diversity). Additionally or alternatively, multi-user evaluator  304  may provide any disparate user specific metrics such as a PathLossMetric as described below; thus, where multi-user evaluator  304  generates MudMetric and PathLossMetric, UserSpecificMetric=MudMetric+PathLossMetric. Moreover, token manager  302  may utilize substantially similar calculations based upon substantially similar parameters for a class of users to generate TokenMetric. Additionally, token manager  302  may update TokenMetric simultaneously for users in a common class. Further, multi-user evaluator  304  may employ user specific parameters to obtain MudMetric and/or PathLossMetric.
 
     Token manager  302  may track historical data to determine an overall number of times a user has been assigned to use the channel. Further, token manager  302  may generate a fairness metric (TokenMetric) that may be provided to enhance user selector  112 . Moreover, token manager  302  may update the token of a user as follows: Token(t+1)=Token(t)+ulTokenUpdateRate−ulAsgFlag(t)*ulWtTxFrms, where ulTokenUpdateRate may be determined by a service class (e.g., QoS data) of the user. For example, ulTokenUpdateRate may be 64 for best-effort users and 128 for delay-sensitive users; however, the claimed subject matter is not so limited. Further, ulAsgFlag(t) may be the recorded number of segments the user is assigned to in time-frequency slot t (e.g., ulAsgFlag(t) ε {0,1,2}). Additionally, ulWtTxFrms may determine the amount of token reduction when a user is scheduled; for example, ulWtTxFrms may be chosen by token manager  302  to make the token algorithm unbiased in the sense that token drift in the long run may be approximately zero. Hence, token manager  302  may evaluate ulWtTxFrms=ulTokenUpdateRate*|U|*8/11. For example, the constant term 8/11 may be based upon an uplink segment alignment with 11 segments in 8 slots; however, any number of segments and/or slots may be utilized. Additionally, token manager  302  may utilize a hard limit for the maximum and minimum token allowed. Moreover, token manager  302  may effectuate a period macro token update algorithm to keep the average token in each sector server unchanged over time. The TokenMetric of a user may be determined by token manager  302  as TokenMetric=Token*ulTokenWt, where ulTokenWt may be 0.01, according to an example. 
     Multi-user evaluator  304  may enable channel conditions to be considered in connection with uplink scheduling. According to an example, multi-user evaluator  304  may utilize a DCCH backoff report to represent, the uplink channel condition. DCCH backoff is controlled by a close-loop uplink power control mechanism. Pursuant to another illustration, multi-user evaluator  304  may represent the uplink channel quality based upon an instantaneous path loss ratio or a path loss ratio available during beacon slots. In accordance with a further example, multi-user evaluator  304  may utilize a downlink signal-to-noise (SNR) report to represent the uplink channel quality (e.g., for the single uplink receive antenna case assuming full symmetry between uplink and downlink channels). 
     Moreover, multi-user evaluator  304  may analyze a remaining power at each mobile. For example, assuming that there are two users, one with good channel quality but only enough power to support the lowest rate option (e.g., since this user has been assigned a couple of TCH segments in flight), while a second user has a diminished channel quality in comparison but enough power to support a much higher rate option, multi-user evaluator  304  may schedule the second user rather than the first user. Multi-user evaluator  304  may utilize an available DCCH backoff to represent the remaining power level, which may be calculated on a per-user basis as: 
             AvailBackoff   =       min   (       10   ⁢           ⁢       log   10     (     PowerAvail   PowerDcch     )       ,     AvailBackoff   max       )     .           
Note here that the available backoff is hard limited by a ceiling, AvailBackoff max =10 log 10 (PowerTch(MaxRateOption)*MaxNumTonesAvail/PowerDcch), which mitigates placing too much priority on users with more than necessary remaining power. Further, PowerTch(MaxRateOption) may be a power required for a maximum rate option.
 
     Multi-user evaluator  304  may generate the multi-user metric for a user based upon the following:
 
MudMetric=((1− ul Backoff Wt )*AvailBackoff+ ul Backoff Wt *( Dcch Backoff− Dcch BackoffAverage))*BackoffScale.
 
Accordingly, BackoffScale may be 10.0. Further, ulBackoffWt may be utilized to control fairness of uplink scheduler  110  among users. When ulBackoffWt approaches 1, users will get a substantially similar number of assigned segments, and when ulBackoffWt becomes smaller, more priority may be given to users with good channel quality. According to an example, 0.75 may be utilized as a moderate scheduler setting of ulBackoffWt and 0.10 may be an aggressive scheduler setting. Moreover, DcchBackOff may be determined as follows:
 
             DcchBackOff   =     10   ⁢         log   10     (     MaxPowerAllowed   PowerDcch     )     .             
Further, DcchBackOffAverage may be an average of DcchBackOff over the last n slots where n may be 700, for instance (e.g., 1 sec averaging). Also, MaxPowerAllowed may be a maximum total power a user is allowed to transmit and PowerDcch may be a current DCCH transmission power.
 
     According to another example, multi-user evaluator  304  may consider an interference caused by each user as an additional metric (e.g., PathLossMetric). PathLossMetric yielded by multi-user evaluator  304  may be another user specific metric similar to the MudMetric. Assuming other conditions remain constant, users that cause less interference to other cells may be scheduled rather than users that cause greater amounts of such interference. According to an example, the average path loss ratio, the instantaneous path loss ratio and/or the downlink SNR can be used to capture this effect of inter-cell interference. For instance, multi-user evaluator  304  may utilize the average path loss ratio and the PathLossMetric may be calculated on a per user basis as: PathLossMetric=PathLossRatio*PathLossScale*PathLossWt, where PathLossScale may be 32 and PathLossWt may be 1; however, the claimed subject matter is not so limited. 
     Upon user selector  112  assigning a user to a traffic channel, rate selector  114  may assign a code rate. Rate selector  114  may include a nominal power analyzer  306  that enables determining a nominal power, P nom . Nominal power analyzer  306  may generate P nom  based upon an interference measurement. For example, nominal power analyzer  306  may evaluate P nom =β1, where β is related to a loading factor (e.g., β&lt;1) and I is an interference measured by base station  102  on a per tone basis. 
     Rate selector  114  may thereafter analyze 
               P   =     min   ⁡     (         1   α     ⁢     P   nom       ,     P   max       )         ,         
where α is an interference cost (e.g., signaled by a mobile device) and P max  is a maximum transmit power, to determine a power that can be utilized for uplink transmission. Based upon P, rate selector  114  may calculate a signal-to-noise ratio,
 
               SNR   =     P   I       ,         
which may map to a rate. Thus, rate selector  114  may determine the rate, R, to be utilized by the mobile device by evaluating R=log(1+SNR). The rate may thereafter be incorporated into an assignment sent to a mobile device over the downlink.
 
     The following provides further examples related to rate selection. The set of users allocated on traffic channels that share the same time slot may have their rates, r(i), chosen. Multiple traffic channels can share the same time slot. A given traffic channel can have one user selected through the user selection part (e.g., user selector  112 ). When the user comes up for rate allocation, rates allocated to users in other traffic channels that have already been scheduled and share the same time slot may be evaluated. For example, the nominal power yielded by nominal power analyzer  306  may be altered based upon considerations related to users scheduled in other traffic channels. Further to this example, power allocated to the other traffic channels sharing the same time slot may be subtracted out and the remaining P nom  may be utilized for the rate calculation as described above. If more than one traffic channel has come up for scheduling in the time slot, then the rate allocation on both the traffic channels may be jointly evaluated. For instance, if two traffic channels are to be scheduled in a time slot, rate selector  114  yields two rates, where an evaluation of the rates may be effectuated jointly in that the available P nom  may be split in an appropriate manner between two users. According to the foregoing and providing further illustration, the following rate selection criterion (e.g., which may provide a bound to the total interference generated by mobiles inside the same sector server) may be utilized: 
                     ∑     i   ⁢     :     ⁢   UsersTransmittingDech       ⁢           ⁢       r   i     *     γ   0         +       ∑     i   ⁢     :     ⁢   UsersAssignedOnTrafficChannelsSharingCurrentTimeSlot       ⁢           ⁢       r   i     *     β   ⁡     (     r   ⁡     (   i   )       )       ⁢       N   t     ⁡     (   i   )             ≤     N   data       ,         
where r i  may be a pathloss ratio and/or interference cost. For clarity sake, lets mention that ‘i’ is an index into a set of mobile terminals. Additionally, γ 0  may be a targeted dcch snr, N t (i) may be a number of tones in a particular traffic channel that have come up for allocation, and N data  may be a number of data tones in the OFDM system. Further,
 
     
       
         
           
             
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     To allocate the interference budget among different traffic channels, uplink scheduler  110  may consider the following factors: the spectral efficiency of the overall system, traffic requests sent by the terminal, the interference budget remaining and user QoS class. A baseline mechanism may be that the interference budget is proportional to the number of tones in the traffic channel coming up for rate assignment. Further, uplink scheduler  110  may choose to offset the interference budget based on the factors mentioned above, which allow the mobiles using corresponding traffic channels to deviate from the baseline interference budget. 
     Referring to  FIGS. 4-6 , methodologies relating to uplink scheduling in OFDM systems are illustrated. While, for purposes of simplicity of explanation, the methodologies are shown and described as a series of acts, it is to be understood and appreciated that the methodologies are not limited by the order of acts, as some acts may, in accordance with one or more embodiments, occur in different orders and/or concurrently with other acts from that shown and described herein. For example, those skilled in the art will understand and appreciate that a methodology could alternatively be represented as a series of interrelated states or events, such as in a state diagram. Moreover, not all illustrated acts may be required to implement a methodology in accordance with one or more embodiments. 
     Turning to  FIG. 4 , illustrated is a methodology  400  that facilitates uplink scheduling in an OFDM environment. At  402 , a user may be selected to transmit on an uplink traffic channel during a time-frequency slot as a function of a token value. For example, a number of tokens may be distributed to various users, and as uplink assignments are made to the users, some number of tokens may be subtracted from a total associated with each of the users. Moreover, current token values from a plurality of users may be analyzed and a particular user may be selected according to this analysis. Additionally or alternatively, a number of tokens remaining for a particular user may be measured by an interference cost, a traffic priority, a maximum power available for transmission by the user, and/or a time from a last assignment to the user. According to another example, QoS classes may be considered when analyzing a number of tokens associated with users. At  404 , a rate for transmission on the uplink channel by the user may be determined. By way of illustration, the rate may be selected to mitigate interference. Further, the rate may be selected as a function of an interference cost and/or a maximum power available for transmission by the user. At  406 , an assignment may be sent to the user. For example, the assignment may include information related to time, frequency, rate, modulation, and so forth, which may be utilized for transmission over an uplink. 
     Now referring to  FIG. 5 , illustrated is a methodology  500  that facilitates scheduling uplink transmissions by utilizing information obtained from mobile devices. At  502 , information signaled on an uplink may be received. For example, the information may include interference costs measured by mobile devices (e.g., Beacon ratio report, path loss report, . . . ), traffic priorities, and/or maximum power available at mobile devices for transmission. At  504 , a token metric and a multi-user diversity metric may be determined based upon the received information. Additionally or alternatively, the token metric and the multi-user diversity metric may be evaluated based upon data related to a time since a previous assignment to a mobile device and/or QoS classes of users. At  506 , a mobile device may be chosen to transmit on an uplink traffic channel during a time-frequency slot based upon the token metric and the multi-user diversity metric. For example, a user with a largest combination of the two metrics may be selected. At  508 , a rate for uplink transmission may be controlled based upon the received information. Thus, for the chosen mobile device, the interference cost and/or the maximum power available may be considered in connection with selecting the rate. By way of example, a nominal power may be obtained. Thereafter, a transmission power may be selected by evaluating 
               P   =     min   ⁡     (         1   α     ⁢     P   nom       ,     P   max       )         ,         
where α is the interference cost and P max  is a maximum power available. Further, a SNR may be calculated by dividing the transmission power, P, by a per tone interference measured at a base station. Moreover, the rate may map to the SNR, and may be obtained by analyzing R=log(1+SNR). At  310 , an assignment may be transmitted to the mobile device on a downlink.
 
     With reference to  FIG. 6 , illustrated is a methodology  600  that facilitates signaling information over an uplink in connection with obtaining a scheduled assignment for transmission over the uplink. At  602 , information including a Beacon ratio report, a traffic priority, and a maximum power available may be signaled to a base station over an uplink. According to an example, the information may be sent as part of a request; however, the claimed subject matter is not so limited. At  604 , an uplink assignment including a rate may be obtained from the base station, where the assignment may be generated at least in part upon the signaled information. For example, the signaled information may be employed by the base station to determine a token metric and/or a multi-user diversity metric. Further, the base station may consider such metrics in connection with yielding the assignment. At  606 , traffic may be transmitted on the uplink by employing the assignment. Thus, uplink transmission may be effectuated at a frequency, time, rate, etc. specified in the assignment. 
     It will be appreciated that, in accordance with one or more aspects described herein, inferences can be made regarding selecting users and/or rates in connection with scheduling uplink transmission. As used herein, the term to “infer” or “inference” refers generally to the process of reasoning about or inferring states of the system, environment, and/or user from a set of observations as captured via events and/or data. Inference can be employed to identify a specific context or action, or can generate a probability distribution over states, for example. The inference can be probabilistic—that is, the computation of a probability distribution over states of interest based on a consideration of data and events. Inference can also refer to techniques employed for composing higher-level events from a set of events and/or data. Such inference results in the construction of new events or actions from a set of observed events and/or stored event data, whether or not the events are correlated in close temporal proximity, and whether the events and data come from one or several event and data sources. 
     According to an example, one or more methods presented above can include making inferences regarding analyzing an interference cost associated with uplink transmission; the inferred interference cost may be signaled to a base station to enable uplink scheduling. By way of further illustration, an inference may be made related to a priority of data to be transmitted via an uplink traffic channel, and the inferred priority may be employed in connection with selecting users for uplink assignments. It will be appreciated that the foregoing examples are illustrative in nature and are not intended to limit the number of inferences that can be made or the manner in which such inferences are made in conjunction with the various embodiments and/or methods described herein. 
       FIG. 7  depicts an example communication system  700  implemented in accordance with various aspects including multiple cells: cell I  702 , cell M  704 . Note that neighboring cells  702 ,  704  overlap slightly, as indicated by cell boundary region  768 , thereby creating potential for signal interference between signals transmitted by base stations in neighboring cells. Each cell  702 ,  704  of system  700  includes three sectors. Cells which have not be subdivided into multiple sectors (N=1), cells with two sectors (N=2) and cells with more than 3 sectors (N&gt;3) are also possible in accordance with various aspects. Cell  702  includes a first sector, sector I  710 , a second sector, sector II  712 , and a third sector, sector III  714 . Each sector  710 ,  712 ,  714  has two sector boundary regions; each boundary region is shared between two adjacent sectors. 
     Sector boundary regions provide potential for signal interference between signals transmitted by base stations in neighboring sectors. Line  716  represents a sector boundary region between sector I  710  and sector II  712 ; line  718  represents a sector boundary region between sector II  712  and sector III  714 ; line  720  represents a sector boundary region between sector III  714  and sector I  710 . Similarly, cell M  704  includes a first sector, sector I  722 , a second sector, sector II  724 , and a third sector, sector III  726 . Line  728  represents a sector boundary region between sector I  722  and sector II  724 ; line  730  represents a sector boundary region between sector II  724  and sector III  726 ; line  732  represents a boundary region between sector III  726  and sector I  722 . Cell I  702  includes a base station (BS), base station I  706 , and a plurality of end nodes (ENs) (e.g., mobile devices) in each sector  710 ,  712 ,  714 . Sector I  710  includes EN( 1 )  736  and EN(X)  738  coupled to BS  706  via wireless links  740 ,  742 , respectively; sector II  712  includes EN( 1 ′)  744  and EN(X′)  746  coupled to BS  706  via wireless links  748 ,  750 , respectively; sector III  714  includes EN( 1 ″)  752  and EN(X″)  754  coupled to BS  706  via wireless links  756 ,  758 , respectively. Similarly, cell M  704  includes base station M  708 , and a plurality of end nodes (ENs) in each sector  722 ,  724 ,  726 . Sector I  722  includes EN( 1 )  736 ′ and EN(X)  738 ′ coupled to BS M  708  via wireless links  740 ′,  742 ′, respectively; sector II  724  includes EN( 1 ′)  744 ′ and EN(X′)  746 ′ coupled to BS M  708  via wireless links  748 ′,  750 ′, respectively; sector 3  726  includes EN( 1 ″)  752 ′ and EN(X″)  754 ′ coupled to BS  708  via wireless links  756 ′,  758 ′, respectively. 
     System  700  also includes a network node  760  which is coupled to BS I  706  and BS M  708  via network links  762 ,  764 , respectively. Network node  760  is also coupled to other network nodes, e.g., other base stations, AAA server nodes, intermediate nodes, routers, etc. and the Internet via network link  766 . Network links  762 ,  764 ,  766  may be, e.g., fiber optic cables. Each end node, e.g., EN( 1 )  736  may be a wireless terminal including a transmitter as well as a receiver. The wireless terminals, e.g., EN( 1 )  736  may move through system  700  and may communicate via wireless links with the base station in the cell in which the EN is currently located. The wireless terminals, (WTs), e.g., EN( 1 )  736 , may communicate with peer nodes, e.g., other WTs in system  700  or outside system  700  via a base station, e.g., BS  706 , and/or network node  760 . WTs, e.g., EN( 1 )  736  may be mobile communications devices such as cell phones, personal data assistants with wireless modems, etc. Respective base stations perform tone subset allocation using a different method for the strip-symbol periods, from the method employed for allocating tones and determining tone hopping in the rest symbol periods, e.g., non strip-symbol periods. The wireless terminals use the tone subset allocation method along with information received from the base station, e.g., base station slope ID, sector ID information, to determine tones that they can employ to receive data and information at specific strip-symbol periods. The tone subset allocation sequence is constructed, in accordance with various aspects to spread inter-sector and inter-cell interference across respective tones. 
       FIG. 8  illustrates an example base station  800  in accordance with various aspects. Base station  800  implements tone subset allocation sequences, with different tone subset allocation sequences generated for respective different sector types of the cell. Base station  800  may be used as any one of base stations  706 ,  708  of the system  700  of  FIG. 7 . The base station  800  includes a receiver  802 , a transmitter  804 , a processor  806 , e.g., CPU, an input/output interface  808  and memory  810  coupled together by a bus  809  over which various elements  802 ,  804 ,  806 ,  808 , and  810  may interchange data and information. 
     Sectorized antenna  803  coupled to receiver  802  is used for receiving data and other signals, e.g., channel reports, from wireless terminals transmissions from each sector within the base station&#39;s cell. Sectorized antenna  805  coupled to transmitter  804  is used for transmitting data and other signals, e.g., control signals, pilot signal, beacon signals, etc. to wireless terminals  900  (see  FIG. 9 ) within each sector of the base station&#39;s cell. In various aspects, base station  800  may employ multiple receivers  802  and multiple transmitters  804 , e.g., an individual receiver  802  for each sector and an individual transmitter  804  for each sector. Processor  806 , may be, e.g., a general purpose central processing unit (CPU). Processor  806  controls operation of base station  800  under direction of one or more routines  818  stored in memory  810  and implements the methods. I/O interface  808  provides a connection to other network nodes, coupling the BS  800  to other base stations, access routers, AAA server nodes, etc., other networks, and the Internet. Memory  810  includes routines  818  and data/information  820 . 
     Data/information  820  includes data  836 , tone subset allocation sequence information  838  including downlink strip-symbol time information  840  and downlink tone information  842 , and wireless terminal (WT) data/info  844  including a plurality of sets of WT information: WT  1  info  846  and WT N info  860 . Each set of WT info, e.g., WT  1  info  846  includes data  848 , terminal ID  850 , sector ID  852 , uplink channel information  854 , downlink channel information  856 , and mode information  858 . 
     Routines  818  include communications routines  822  and base station control routines  824 . Base station-control routines  824  includes a scheduler module  826  and signaling routines  828  including a tone subset allocation routine  830  for strip-symbol periods, other downlink tone allocation hopping routine  832  for the rest of symbol periods, e.g., non strip-symbol periods, and a beacon routine  834 . 
     Data  836  includes data to be transmitted that will be sent to encoder  814  of transmitter  804  for encoding prior to transmission to WTs, and received data from WTs that has been processed through-decoder  812  of receiver  802  following reception. Downlink strip-symbol time information  840  includes the frame synchronization structure information, such as the super slot, beaconslot, and ultraslot structure information and information specifying whether a given symbol period is a strip-symbol period, and if so, the index of the strip-symbol period and whether the strip-symbol is a rescuing point to truncate the tone subset allocation sequence used by the base station. Downlink tone information  842  includes information including a carrier frequency assigned to the base station  800 , the number and frequency of tones, and the set of tone subsets to be allocated to the strip-symbol periods, and other cell and sector specific values such as slope, slope index and sector type. 
     Data  848  may include data that WT1  900  has received from a peer node, data that WT 1  900  desires to be transmitted to a peer node, and downlink channel quality report feedback information. Terminal ID  850  is a base station  800  assigned ID that identifies WT 1  900 . Sector ID  852  includes information identifying the sector in which WT1  900  is operating. Sector ID  852  can be used, for example, to determine the sector type. Uplink channel information  854  includes information identifying channel segments that have been allocated by scheduler  826  for WT1  900  to use, e.g., uplink traffic channel segments for data, dedicated uplink-control channels for requests, power control, timing control, etc. Each uplink channel assigned to WT1  900  includes one or more logical tones, each logical tone following an uplink hopping sequence. Downlink channel information  856  includes information identifying channel segments that have been allocated by scheduler  826  to carry data and/or information to WT1  900 , e.g., downlink traffic channel segments for user data. Each downlink channel assigned to WT1  900  includes one or more logical tones, each following a downlink hopping sequence. Mode information  858  includes information identifying the state of operation of WT1  900 , e.g. sleep, hold, on. 
     Communications routines  822  control the base station  800  to perform various communications operations and implement various communications protocols. Base station control routines  824  are used to control the base station  800  to perform basic base station functional tasks, e.g., signal generation and reception, scheduling, and to implement the steps of the method of some aspects including transmitting signals to wireless terminals using the tone subset allocation sequences during the strip-symbol periods. 
     Signaling routine  828  controls the operation of receiver  802  with its decoder  812  and transmitter  804  with its encoder  814 . The signaling routine  828  is responsible for controlling the generation of transmitted data  836  and control information. Tone subset allocation routine  830  constructs the tone subset to be used in a strip-symbol period using the method of the aspect and using data/information  820  including downlink strip-symbol time info  840  and sector ID  852 . The downlink tone subset allocation sequences will be different for each sector type in a cell and different for adjacent cells. The WTs  900  receive the signals in the strip-symbol periods in accordance with the downlink tone subset allocation sequences; the base station  800  uses the same downlink tone subset allocation sequences in order to generate the transmitted signals. Other downlink tone allocation hopping routine  832  constructs downlink tone hopping sequences, using information including downlink tone information  842 , and downlink channel information  856 , for the symbol periods other than the strip-symbol periods. The downlink data tone hopping sequences are synchronized across the sectors of a cell. Beacon routine  834  controls the transmission of a beacon signal, e.g., a signal of relatively high power signal concentrated on one or a few tones, which may be used for sychronization purposes, e.g., to synchronize the frame timing structure of the downlink signal and therefore the tone subset allocation sequence with respect to an ultra-slot boundary. 
       FIG. 9  illustrates an example wireless terminal (e.g., end node, mobile device, . . . )  900  which can be used as any one of the wireless terminals (e.g., end nodes, mobile devices, . . . ), e.g., EN( 1 )  736 , of the system  700  shown in  FIG. 7 . Wireless terminal  900  implements the tone subset allocation sequences. The wireless terminal  900  includes a receiver  902  including a decoder  912 , a transmitter  904  including an encoder  914 , a processor  906 , and memory  908  which are coupled together by a bus  910  over which the various elements  902 ,  904 ,  906 ,  908  can interchange data and information. An antenna  903  used for receiving signals from a base station  800  is coupled to receiver  902 . An antenna  905  used for transmitting signals, e.g., to base station  800  is coupled to transmitter  904 . 
     The processor  906 , e.g., a CPU controls the operation of the wireless terminal  900  and implements methods by executing routines  920  and using data/information  922  in memory  908 . 
     Data/information  922  includes user data  934 , user information  936 , and tone subset allocation sequence information  950 . User data  934  may include data, intended for a peer node, which will be routed to encoder  914  for encoding prior to transmission by transmitter  904  to base station  800 , and data received from the base station  800  which has been processed by the decoder  912  in receiver  902 . User information  936  includes uplink channel information  938 , downlink channel information  940 , terminal ID information  942 , base station ID information  944 , sector ID information  946 , and mode information  948 . Uplink channel information  938  includes information identifying uplink channels segments that have been assigned by base station  800  for wireless terminal  900  to vise when transmitting to the base station  800 . Uplink channels may include uplink traffic channels, dedicated uplink control channels, e.g., request channels, power control channels and timing control channels. Each uplink channel includes one or more logic tones, each logical tone following an uplink tone hopping sequence. The uplink hopping sequences are different between each sector type of a cell and between adjacent cells. Downlink channel information  940  includes information identifying downlink channel segments that have been assigned by base station  800  to WT  900  for use when BS  800  is transmitting data/information to WT  900 . Downlink channels may include downlink traffic channels and assignment channels, each downlink channel including one or more logical tone, each logical tone following a downlink hopping sequence, which is synchronized between each sector of the cell. 
     User info  936  also includes terminal ID information  942 , which is a base station  800  assigned identification, base station ID information  944  which identifies the specific base station  800  that WT has established communications with, and sector ID info  946  which identifies the specific sector of the cell where WT  900  is presently located. Base station ID  944  provides a cell slope value and sector ID info  946  provides a sector index type; the cell slope value and sector index type may be used to derive tone hopping sequences. Mode information  948  also included in user info  936  identifies whether the WT  900  is in sleep mode, hold mode, or on mode. 
     Tone subset allocation sequence information  950  includes downlink strip-symbol time information  952  and downlink tone information  954 . Downlink strip-symbol time information  952  include the frame synchronization structure information, such as the superslot, beaconslot, and ultraslot structure information and information specifying whether a given symbol period is a strip-symbol period, and if so, the index of the strip-symbol period and whether the strip-symbol is a resetting point to truncate the tone subset allocation sequence used by the base station. Downlink tone info  954  includes information including a carrier frequency assigned to the base station  800 , the number and frequency of tones, and the set of tone subsets to be allocated to the strip-symbol periods, and other cell and sector specific values such as slope, slope index and sector type. 
     Routines  920  include communications routines  924  and wireless terminal control routines  926 . Communications routines  924  control the various communications protocols used by WT  900 . Wireless terminal control routines  926  control basic wireless terminal  900  functionality including the control of the receiver  902  and transmitter  904 . Wireless terminal control routines  926  include the signaling routine  928 . The signaling routine  928  includes a tone subset allocation routine  930  for the strip-symbol periods and an other downlink tone allocation hopping routine  932  for the rest of symbol periods, e.g., non strip-symbol periods. Tone subset allocation routine  930  uses user data/information  922  including downlink channel information  940 , base station ID info  944 , e.g., slope index and sector type, and downlink tone information  954  in order to generate the downlink tone subset allocation sequences in accordance with some aspects and process received data transmitted from base station  800 . Other downlink tone allocation hopping routine  930  constructs downlink tone hopping sequences, using information including downlink tone information  954 , and downlink channel information  940 , for the symbol periods other than the strip-symbol periods. Tone subset allocation routine  930 , when executed by processor  906 , is used to determine when and on which tones the wireless terminal  900  is to receive one or more strip-symbol signals from the base station  800 . The uplink tone allocation hopping routine  930  uses a tone subset allocation function, along with information received from the base station  800 , to determine the tones in which it should transmit on. 
     With reference to  FIG. 10 , illustrated is a system  1000  that schedules uplink transmission on traffic channels. For example, system  1000  may reside at least partially within a base station. It is to be appreciated that system  1000  is represented as including functional blocks, which may be functional blocks that represent functions implemented by a processor, software, or combination thereof (e.g., firmware). System  1000  includes a logical grouping  1002  of electrical components that can act in conjunction. For instance, logical grouping  1002  may include an electrical component for selecting a mobile device for uplink transmission based upon a token metric and a multi-user diversity metric  1004 . For example, the token metric and the multi-user diversity metric may be determined based upon interference costs, traffic priorities, maximum power available for mobile device transmission, time spans since previous assignments, and/or QoS classes. Further, logical grouping  1002  may comprise an electrical component for identifying a rate for the uplink transmission based upon interference mitigation  1006 . For example, the rate may be evaluated as a function of interference cost and maximum power available for mobile device transmission. Also, logical grouping  1002  may include an electrical component for transmitting an assignment to the mobile device  1008 , where the assignment includes data related to the rate. By way of illustration, the assignment may additionally include data associated with a frequency, time, modulation, and so forth that may be leveraged by the mobile device for transmission on an uplink traffic channel. Additionally, system  1000  may include a memory  1010  that retains instructions for executing functions associated with electrical components  1004 ,  1006  and  1008 . While shown as being external to memory  1010 , it is to be understood that one or more of electrical components  1004 ,  1006  and  1008  may exist within memory  1010 . 
     Now referring to  FIG. 11 , illustrated is a system  1100  that signals a measured interference cost to a base station in connection with obtaining an uplink assignment. System  1100  may reside within a mobile device, for instance. As depicted, system  1100  includes functional blocks that may represent functions implemented by a processor, software, or combination thereof (e.g., firmware). System  1100  includes a logical grouping  1102  of electrical components that facilitate obtaining access to an uplink traffic channel. Logical grouping  1102  may include an electrical component for measuring an interference cost  1104 . For example, the interference cost may be a Beacon ratio report, a path loss report, and so forth. Further, the interference cost may be a function of loading factors obtained from a plurality of base stations. Moreover, logical grouping  1102  may include an electrical component for transmitting the measured interference cost on an uplink  1106 . By way of example, traffic priority data and/or a maximum power available for uplink transmission may additionally or alternatively be signaled on the uplink. Further logical grouping  1102  may comprise an electrical component for receiving an assignment allocated as a function of a token value  1108 , where the token value is determined based upon the interference cost. Further, the token value may be obtained as a function of the traffic priority data and/or the maximum power available. Moreover, a multi-user diversity metric may be utilized to generate the assignment. Also, logical grouping  1102  may include an electrical component for transmitting on an uplink traffic channel based upon the assignment  1110 , where the assignment controls a rate (e.g., code rate). Additionally, system  1100  may include a memory  1112  that retains instructions for executing functions associated with electrical components  1104 ,  1106 ,  1108 , and  1110 . While shown as being external to memory  1112 , it is to be understood that electrical components  1104 ,  1106 ,  1108 , and  1110  may exist within memory  1112 . 
     It is to be understood that the embodiments described herein may be implemented in hardware, software, firmware, middleware, microcode, or any combination thereof. For a hardware implementation, the processing units may be implemented within one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof. 
     When the embodiments are implemented in software, firmware, middleware or microcode, program code or code segments, they may be stored in a machine-readable medium, such as a storage component. A code segment may represent a procedure, a function, a subprogram, a program, a routine, a subroutine, a module, a software package, a class, or any combination of instructions, data structures, or program statements. A code segment may be coupled to another code segment or a hardware circuit by passing and/or receiving information, data, arguments, parameters, or memory contents. Information, arguments, parameters, data, etc. may be passed, forwarded, or transmitted using any suitable means including memory sharing, message passing, token passing, network transmission, etc. 
     For a software implementation, the techniques described herein may be implemented with modules (e.g., procedures, functions, and so on) that perform the functions described herein. The software codes may be stored in memory units and executed by processors. The memory unit may be implemented within the processor or external to the processor, in which case it can be communicatively coupled to the processor via various means as is known in the art. 
     What has been described above includes examples of one or more embodiments. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the aforementioned embodiments, but one of ordinary skill in the art may recognize that many further combinations and permutations of various embodiments are possible. Accordingly, the described embodiments are intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims. Furthermore, to the extent that the term “includes” is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term “comprising” as “comprising” is interpreted when employed as a transitional word in a claim.