Utility maximization scheduler for broadband wireless communication systems

Abstract

Certain aspects of the present disclosure relate to a technique of designing a Media Access Control (MAC) scheduler for uplink communication in high rate wireless data systems, such as Long Term Evolution (LTE) wireless communication systems.

1 . A method for wireless communications, comprising:
 scheduling, among a plurality of users served by an apparatus based on at least one of a defined utility function, a maximum transmit power or a maximum transmit power spectral density (PSD) for each of the users, power and bandwidth resources of an uplink between the users and the apparatus; and   selecting, based on at least one of channel conditions, traffic priorities, marginal utility functions or expected transmitting rates associated with the users, at least one of the users for transmitting data to the apparatus using at least a portion of the scheduled uplink resources.   
     
     
         2 . The method of  claim 1 , wherein:
 each of the utility functions is defined for a flow of packets to be transmitted over the uplink, and   the utility function is a function of a short-term rate assigned to the flow of packets.   
     
     
         3 . The method of  claim 1 , wherein:
 each of the utility functions is defined for a best-effort flow of packets to be transmitted over the uplink, and   the utility function has a large slope at its origin.   
     
     
         4 . The method of  claim 1 , further comprising:
 determining a level of interference caused by each of the users to one or more other users served by one or more other apparatuses;   adapting, based on the level of interference, the maximum transmit power and the maximum transmit PSD; and   scheduling the resources among the users based at least in part on the adapted maximum transmit power and the adapted maximum transmit PSD for each of the users.   
     
     
         5 . The method of  claim 1 , wherein:
 the resources are scheduled for transmitting in one or more sub-frames from each of the at least one selected user, and   an achievable rate of transmitting in the sub-frames depends on a number of assignments associated with the user for duration of the sub-frames.   
     
     
         6 . The method of  claim 5 , wherein:
 the scheduled power resources comprise a maximum allowable transmit power for each of the sub-frames.   
     
     
         7 . The method of  claim 1 , further comprising:
 determining, for every frequency sub-band from a plurality of frequency sub-bands, a portion of the resources scheduled for each of the users; and   assigning one of the frequency sub-bands to one of the users, wherein the portion of resources associated with the assigned frequency sub-band comprises a largest bandwidth resource determined among all the frequency sub-bands for that user.   
     
     
         8 . An apparatus for wireless communications, comprising:
 means for scheduling, among a plurality of users served by the apparatus based on at least one of a defined utility function, a maximum transmit power or a maximum transmit power spectral density (PSD) for each of the users, power and bandwidth resources of an uplink between the users and the apparatus; and   means for selecting, based on at least one of channel conditions, traffic priorities, marginal utility functions or expected transmitting rates associated with the users, at least one of the users for transmitting data to the apparatus using at least a portion of the scheduled uplink resources.   
     
     
         9 . The apparatus of  claim 8 , wherein:
 each of the utility functions is defined for a flow of packets to be transmitted over the uplink, and   the utility function is a function of a short-term rate assigned to the flow of packets.   
     
     
         10 . The apparatus of  claim 8 , wherein:
 each of the utility functions is defined for a best-effort flow of packets to be transmitted over the uplink, and   the utility function has a large slope at its origin.   
     
     
         11 . The apparatus of  claim 8 , further comprising:
 means for determining a level of interference caused by each of the users to one or more other users served by one or more other apparatuses;   means for adapting, based on the level of interference, the maximum transmit power and the maximum transmit PSD; and   means for scheduling the resources among the users based at least in part on the adapted maximum transmit power and the adapted maximum transmit PSD for each of the users.   
     
     
         12 . The apparatus of  claim 8 , wherein:
 the resources are scheduled for transmitting in one or more sub-frames from each of the at least one selected user, and   an achievable rate of transmitting in the sub-frames depends on a number of assignments associated with the user for duration of the sub-frames.   
     
     
         13 . The apparatus of  claim 12 , wherein:
 the scheduled power resources comprise a maximum allowable transmit power for each of the sub-frames.   
     
     
         14 . The apparatus of  claim 8 , further comprising:
 means for determining, for every frequency sub-band from a plurality of frequency sub-bands, a portion of the resources scheduled for each of the users; and   means for assigning one of the frequency sub-bands to one of the users, wherein the portion of resources associated with the assigned frequency sub-band comprises a largest bandwidth resource determined among all the frequency sub-bands for that user.   
     
     
         15 . An apparatus for wireless communications, comprising:
 a scheduler configured to schedule, among a plurality of users served by the apparatus based on at least one of a defined utility function, a maximum transmit power or a maximum transmit power spectral density (PSD) for each of the users, power and bandwidth resources of an uplink between the users and the apparatus; and   a circuit configured to select, based on at least one of channel conditions, traffic priorities, marginal utility functions or expected transmitting rates associated with the users, at least one of the users for transmitting data to the apparatus using at least a portion of the scheduled uplink resources.   
     
     
         16 . The apparatus of  claim 15 , wherein:
 each of the utility functions is defined for a flow of packets to be transmitted over the uplink, and   the utility function is a function of a short-term rate assigned to the flow of packets.   
     
     
         17 . The apparatus of  claim 15 , wherein:
 the resources are scheduled for transmitting in one or more sub-frames from each of the at least one selected user, and   an achievable rate of transmitting in the sub-frames depends on a number of assignments associated with the user for duration of the sub-frames.   
     
     
         18 . The apparatus of  claim 15 , further comprising:
 another circuit configured to determine, for every frequency sub-band from a plurality of frequency sub-bands, a portion of the resources scheduled for each of the users,   wherein the scheduler is also configured to assign one of the frequency sub-bands to one of the users, wherein the portion of resources associated with the assigned frequency sub-band comprises a largest bandwidth resource determined among all the frequency sub-bands for that user.   
     
     
         19 . A computer-program product for wireless communications, comprising a computer readable medium having instructions stored thereon, the instructions being executable by one or more processors and the instructions comprising:
 instructions for scheduling, among a plurality of users served by an apparatus based on at least one of a defined utility function, a maximum transmit power or a maximum transmit power spectral density (PSD) for each of the users, power and bandwidth resources of an uplink between the users and the apparatus; and   instructions for selecting, based on at least one of channel conditions, traffic priorities, marginal utility functions or expected transmitting rates associated with the users, at least one of the users for transmitting data to the apparatus using at least a portion of the scheduled uplink resources.   
     
     
         20 . The computer-program product of  claim 19 , wherein:
 each of the utility functions is defined for a flow of packets to be transmitted over the uplink, and   the utility function is a function of a short-term rate assigned to the flow of packets.   
     
     
         21 . The computer-program product of  claim 19 , wherein:
 the resources are scheduled for transmitting in one or more sub-frames from each of the at least one selected user, and   an achievable rate of transmitting in the sub-frames depends on a number of assignments associated with the user for duration of the sub-frames.   
     
     
         22 . The computer-program product of  claim 19 , wherein the instructions further comprise:
 instructions for determining, for every frequency sub-band from a plurality of frequency sub-bands, a portion of the resources scheduled for each of the users; and   instructions for assigning one of the frequency sub-bands to one of the users, wherein the portion of resources associated with the assigned frequency sub-band comprises a largest bandwidth resource determined among all the frequency sub-bands for that user.   
     
     
         23 . An apparatus for wireless communications, comprising:
 at least one processor configured to
 schedule, among a plurality of users served by the apparatus based on at least one of a defined utility function, a maximum transmit power or a maximum transmit power spectral density (PSD) for each of the users, power and bandwidth resources of an uplink between the users and the apparatus, and 
 select, based on at least one of channel conditions, traffic priorities, marginal utility functions or expected transmitting rates associated with the users, at least one of the users for transmitting data to the apparatus using at least a portion of the scheduled uplink resources; and 
   a memory coupled to the at least one processor.   
     
     
         24 . The apparatus of  claim 23 , wherein:
 each of the utility functions is defined for a flow of packets to be transmitted over the uplink, and   the utility function is a function of a short-term rate assigned to the flow of packets.   
     
     
         25 . The apparatus of  claim 23 , wherein:
 the resources are scheduled for transmitting in one or more sub-frames from each of the at least one selected user, and   an achievable rate of transmitting in the sub-frames depends on a number of assignments associated with the user for duration of the sub-frames.   
     
     
         26 . The apparatus of  claim 23 , wherein the at least one processor is further configured to:
 determine, for every frequency sub-band from a plurality of frequency sub-bands, a portion of the resources scheduled for each of the users; and   assign one of the frequency sub-bands to one of the users, wherein the portion of resources associated with the assigned frequency sub-band comprises a largest bandwidth resource determined among all the frequency sub-bands for that user.   
     
     
         27 . A method for wireless communications, comprising:
 scheduling, among a plurality of logical channels (LCs), packets for transmission over the LCs based at least in part on a defined utility function for each of the LCs,   wherein the utility function is based on at least one of Quality of Service (QoS) parameters of that LC or a priority of that LC relative to one or more other priorities of one or more other LCs of the plurality of LCs.   
     
     
         28 . The method of  claim 27 , wherein the utility function is chosen based on at least one of: one or more QoS Class Identifier (QCI) parameters of the LC, a prioritized bit rate (PBR) of the LC, or the priority of the LC. 
     
     
         29 . The method of  claim 28 , wherein the PBR and the priority are configured by a radio resource controller (RRC) operating in accordance to Long Term Evolution (LTE) wireless communication standard. 
     
     
         30 . The method of  claim 27 , wherein:
 the utility functions are defined for flows of the packets to be transmitted with a Guaranteed Bit Rate (GBR), and   each of the utility functions has a large slope for rates less than the GBR and a smaller slope for rates greater than the GBR.   
     
     
         31 . The method of  claim 27 , wherein:
 the scheduling is further based on a marginal utility function associated with each of the LCs, and   a value of the marginal utility function is constant for a plurality of transmitting rates.   
     
     
         32 . The method of  claim 27 , wherein the utility function is a function of one or more QoS Class Identifier (QCI) parameters defined for a bearer transmission over the LC. 
     
     
         33 . An apparatus for wireless communications, comprising:
 means for scheduling, among a plurality of logical channels (LCs), packets for transmission over the LCs based at least in part on a defined utility function for each of the LCs,   wherein the utility function is based on at least one of Quality of Service (QoS) parameters of that LC or a priority of that LC relative to one or more other priorities of one or more other LCs of the plurality of LCs.   
     
     
         34 . The apparatus of  claim 33 , wherein the utility function is chosen based on at least one of: one or more QoS Class Identifier (QCI) parameters of the LC, a prioritized bit rate (PBR) of the LC, or the priority of the LC. 
     
     
         35 . The apparatus of  claim 34 , wherein the PBR and the priority are configured by a radio resource controller (RRC) operating in accordance to Long Term Evolution (LTE) wireless communication standard. 
     
     
         36 . The apparatus of  claim 33 , wherein:
 the utility functions are defined for flows of the packets to be transmitted with a Guaranteed Bit Rate (GBR), and   each of the utility functions has a large slope for rates less than the GBR and a smaller slope for rates greater than the GBR.   
     
     
         37 . The apparatus of  claim 33 , wherein:
 the scheduling is further based on a marginal utility function associated with each of the LCs, and   a value of the marginal utility function is constant for a plurality of transmitting rates.   
     
     
         38 . The apparatus of  claim 33 , wherein the utility function is a function of one or more QoS Class Identifier (QCI) parameters defined for a bearer transmission over the LC. 
     
     
         39 . An apparatus for wireless communications, comprising:
 a scheduler configured to schedule, among a plurality of logical channels (LCs), packets for transmission over the LCs based at least in part on a defined utility function for each of the LCs,   wherein the utility function is based on at least one of Quality of Service (QoS) parameters of that LC or a priority of that LC relative to one or more other priorities of one or more other LCs of the plurality of LCs.   
     
     
         40 . The apparatus of  claim 39 , wherein the utility function is chosen based on at least one of: one or more QoS Class Identifier (QCI) parameters of the LC, a prioritized bit rate (PBR) of the LC, or the priority of the LC. 
     
     
         41 . The apparatus of  claim 39 , wherein:
 the utility functions are defined for flows of the packets to be transmitted with a Guaranteed Bit Rate (GBR), and   each of the utility functions has a large slope for rates less than the GBR and a smaller slope for rates greater than the GBR.   
     
     
         42 . A computer-program product for wireless communications, comprising a computer readable medium having instructions stored thereon, the instructions being executable by one or more processors and the instructions comprising:
 instructions for scheduling, among a plurality of logical channels (LCs), packets for transmission over the LCs based at least in part on a defined utility function for each of the LCs,   wherein the utility function is based on at least one of Quality of Service (QoS) parameters of that LC or a priority of that LC relative to one or more other priorities of one or more other LCs of the plurality of LCs.   
     
     
         43 . The computer-program product of  claim 42 , wherein the utility function is chosen based on at least one of: one or more QoS Class Identifier (QCI) parameters of the LC, a prioritized bit rate (PBR) of the LC, or the priority of the LC. 
     
     
         44 . The computer-program product of  claim 42 , wherein:
 the utility functions are defined for flows of the packets to be transmitted with a Guaranteed Bit Rate (GBR), and   each of the utility functions has a large slope for rates less than the GBR and a smaller slope for rates greater than the GBR.   
     
     
         45 . An apparatus for wireless communications, comprising:
 at least one processor configured to
 schedule, among a plurality of logical channels (LCs), packets for transmission over the LCs based at least in part on a defined utility function for each of the LCs, 
 wherein the utility function is based on at least one of Quality of Service (QoS) parameters of that LC or a priority of that LC relative to one or more other priorities of one or more other LCs of the plurality of LCs; and 
   a memory coupled to the at least one processor.   
     
     
         46 . The apparatus of  claim 45 , wherein the utility function is chosen based on at least one of: one or more QoS Class Identifier (QCI) parameters of the LC, a prioritized bit rate (PBR) of the LC, or the priority of the LC. 
     
     
         47 . The apparatus of  claim 45 , wherein:
 the utility functions are defined for flows of the packets to be transmitted with a Guaranteed Bit Rate (GBR), and   each of the utility functions has a large slope for rates less than the GBR and a smaller slope for rates greater than the GBR.