Patent Publication Number: US-2007104206-A1

Title: Method and apparatus for allocating channels for data communication in a radio communication system

Description:
The present invention relates generally to the communication of data pursuant to a high-speed data communication service, such as an Enhanced Data for Global Evolution (EDGE) communication service. More particularly, the present invention relates to apparatus, and an associated method, that allocates communication resources according to a Mobile Allocation Index Offset scheme.  
     BACKGROUND OF THE INVENTION  
      High-speed data services are increasingly performed by way of radio communication systems. Advancements in communication technologies have permitted the development and deployment of radio communication systems that permit the communication of data at high communication throughput rates. And, with continued advancements in communication technologies, improvements to such systems permit the throughput rates to be yet further increased. Various high-speed data services, and their associated mechanisms of implementation, are undergoing development, standardization, and implementation. An exemplary data communication service, referred to as GPRS (General Packet Radio Service) for GSM (Global System for Mobile communications) has achieved significant levels of deployment and usage. An extension to the general GPRS communication scheme, EDGE (Enhanced Data for Global Evolution) is presently undergoing deployment. Data throughput rates achievable in an EDGE-capable system are significantly higher than those achievable in its predecessor GPRS system.  
      While EDGE-based communications permit data to be communicated at substantially higher data rates than its GPRS predecessor, data services are becoming, and anticipated to become even more so, data-intensive. There is a continuing need to find ways yet further to increase the data throughput capabilities of EDGE-based communications to facilitate the speedy communication of increasingly data-intensive data communication services that are to be implemented in an EDGE-based, or other high-speed, data communication system.  
      Existing EDGE standard promulgations define, amongst other things, the channel structure used pursuant to EDGE-based communications. Channels are defined upon multiple carriers. But, due to various requirements, effectuation of a single communication service using communication resources upon multiple carriers is presently unavailable due to constraints in the standard promulgation.  
      If a manner could be provided in a high-speed data radio communication system to utilize more fully available time-slot/carrier combinations to perform a communication service, increased data throughput rates and spectral utilization would be achievable.  
      It is in light of this background information that the significant improvements of the present invention have evolved.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  illustrates a functional block diagram of an exemplary communication system that includes an embodiment of the present invention as a portion thereof.  
       FIG. 2  illustrates a representation of exemplary communication resource allocation made pursuant to operation of an embodiment of the present invention.  
       FIG. 3  illustrates a method flow diagram listing the method of operation of an embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION  
      The present invention, accordingly, advantageously provides apparatus, and an associated method, that facilitates communication of data pursuant to a high-speed data communication service, such as an Enhanced Data for Global Evolution (EDGE) communication service or other communication system optionally utilizing frequency hopping.  
      Through operation of an embodiment of the present invention, a manner is provided by which to allocate communication resources across a plurality of radio carriers howsoever logically defined pursuant to a Mobile Allocation Index Offset (MAIO) scheme. The MAIO is an offset value to the actual Radio Frequency (RF) to implement frequency hopping, but is treated logically as an RF carrier itself. The likelihood of time slots being available for allocation across a plurality of carriers is greater than the likelihood of time slots being available for allocation on a single carrier, a limitation of existing allocation schemes.  
      By allocating communication resources across a plurality of index offsets, an increased likelihood that a contiguous series, such as a block, of time slots can be allocated for the performance of a data communication service during a communication session. When a contiguous sequence of time slots is available within a frame, the data is able to be communicated more quickly than when only making use of communication resources upon a single carrier for data communications during a communication session. And, even if contiguous time slots are not allocated, increased numbers of time slots allocated to a data communication session permits its completion due to the greater statistical level of resource allocation.  
      In one aspect of the present invention, the network part of the radio data communication system includes an analyzer that analyzes communication resource requirements needed to, or otherwise requested to, be provided pursuant to communicate data to perform a communication service during a communication session. The analyzer determines, for instance, the number of time slots that are needed to be allocated to the communication session to permit the data to be communicated between a set of communication stations. The determinations made by the analyzer are made, for instance, on a frame-by-frame basis, on a communication session basis, or upon another basis, all in a manner that permits dynamic resource allocation.  
      In another aspect of the present invention, the network part also includes a resource allocator that allocates resources to permit the communication of the data during a communication session to effectuate the communication service. The resource allocations are made, e.g., responsive to analysis of the communication requirements. The resource allocations are made across a plurality of MAIOs (Mobile Allocation Index Offsets) howsoever defined. When particular time slots are available on different index offsets or RF frequencies, allocations are made to communicate data pursuant to the communication session within the time slots of the different index offsets or RF frequencies. More generally, resources allocated by the resource allocator are not limited to selection of time slots on a single mobile allocation index offset or RF frequency but rather are allocated, when available, upon any index offset or frequency that the communication stations, parties to a communication session, are capable of operation.  
      In another aspect of the present invention, a message generator at the network part generates an allocation message that includes values identifying the communication resources allocated to communicate the data pursuant to effectuation of the communication service during a communication session. The allocation message is sent by the network part to a mobile station that is a party to the communication session pursuant to which data is to be communicated. If more than one mobile station is to be a party to the communication session, the allocation message is sent to each of the mobile stations. By sending the allocation message to each mobile station that is to be a party to the communication session, the mobile station is informed of the resource allocations, thereby to permit the mobile station to operate correctly to receive, or to transmit, communication data that is communicated during the communication session.  
      The mobile station includes a detector that detects the allocation message, once broadcast by the network part to the mobile station. The detector ascertains the values of the allocation message thereby to identify the allocated resources.  
      The mobile station also includes a controller that controls operation of the mobile station in response to the communication resources detected by the detector to be used pursuant to the communication of the data.  
      Communication resources are allocated in a manner that facilitates improved data throughput rates of the data that is communicated pursuant to performance of the communication session. The allocation is made to maximize the sum of time slots allocated for the communication session within the constraints of the capabilities of the communication stations that are parties to the communication session and to the reaction times of the communication stations needed to switch to the different radio carriers upon which communication resources are allocable.  
      In these and other aspects, therefore, apparatus, and an associated method, is provided for a communication station operable to communicate data. An analyzer is adapted to receive an indication of a characteristic of the data that is to be communicated by the first communication station. The analyzer is configured to analyze communication requirements required for the communication of the data. A resource allocator is adapted to receive an indication of the analysis made by the analyzer. The resource allocator is configured to allocate resources across a plurality of mobile allocation index offsets or frequencies for communication of the data.  
      In these and other aspects, therefore, further apparatus, and an associated method, is provided for a communication station operable pursuant to communication of data. A detector is configured to detect an allocation message delivered to the communication station. The allocation message identifies communication resources allocated to the communication station pursuant to the communication of the data. The resources that are allocated are allocated across a plurality of mobile allocation index offsets or carrier frequencies, e.g., radio carriers howsoever logically defined. A controller is adapted to receive an indication of detections made by the detector. The controller is configured to control operation of the communication station responsive to the detections.  
      With these and other aspects in mind, therefore, reference is first made to  FIG. 1  that illustrates a communication system, shown generally at  10 . The communication system is operable pursuant to an embodiment of the present invention. In the exemplary implementation, the communication system  10  forms a radio data communication system that provides for EDGE (Enhanced Data for Global Evolution) data services. While the following description shall describe exemplary operation of the communication system in terms of its exemplary implementation to provide for EDGE-based communication services, it should be understood that the teachings of the present invention are analogously applicable to other types of communication systems, e.g., operable pursuant to operating specifications that define other types of communication systems. Accordingly, the description of operation of the communication system  10  is for purposes of explanation only and not of limitation.  
      In the illustration of  FIG. 1 , the communication system includes a set of communication stations, communication stations  12  and  14 . Here, the communication station  12  is representative of elements of a network part of the communication system and shall be referred to, at times, as a network station  12 . And, the communication station  14  is representative of a mobile station and shall, at times, subsequently be referred to as a mobile station. During operation, either of the communication stations  12  and  14  are capable of generating EDGE data for communication to effectuate an EDGE data service during a communication session. Operation shall be described with respect to effectuation of a downlink, EDGE communication service, i.e., EDGE data communicated by the network station  12  for delivery to the mobile station  14 . Operation of the communication system to communicate data in an uplink direction can be analogously described. A communication station  14 ′ is also shown in the figure. The communication station  14 ′ is representative of the multi-access nature of the communication system. During exemplary operation, separate EDGE communication services are effectual with both the communication station  14  and the communication station  14 ′.  
      The communication system operates in general conformity with the EDGE/GPRS/GSM (Enhanced Data for Global Evolution/General Packet Radio Service/Global System for Mobile communications) operating specifications, particularly with respect to the EDGE channel structure defined therein. The EDGE channel structure defines a TDMA (Time Division Multiple Access) scheme including frames that comprise eight time slots. A maximum transmission rate of 59.2 kb/s per time slot is permitted. When a communication service is to be effectuated, communication resources, i.e., time slots within frames defined upon a carrier available for communication, are allocated for the communication of the EDGE data thereon. Theoretically, all eight time slots of a frame can be allocated to a single communication session, thereby permitting a maximum transmission rate of 473.6 kb/s (8*59.2 kb/s=473.6 kb/s). However, in actual practice, allocation of such a large number of time slots on a single carrier, or, more generally, a single mobile allocation index offset or frequency is unachievable. Other operating requirements of the EDGE/GPRS/GSM system necessitate that a mobile station make various measurements, such as measurements that are required to be taken on signals broadcast in adjacent cells, i.e., cells adjacent to the active cell in which the mobile station is positioned. The operating specification, TS 45.008 [5] and TS 45.0002 [2], Annex B specify and define certain of these measurements. Additionally, due to the multi-access nature of the communication system, communication services, both data and traffic services, are performed by other communication station sets. Competition for communication resources limits the availability of contiguous time slots that are available to be allocated to effectuate a communication service. If, for instance, there is a sixty percent probability of availability of a single time slot for assignment, the statistical probability of six contiguous time slots on a single carrier being available is only 4.67 percent. And the probability of eight contiguous time slots on a single carrier being available drops to 1.68 percent. Even putting aside the limitations due to the need of a mobile station to make measurements, there is a statistically small likelihood that multiple, contiguous time slots would be available on a single carrier for allocation pursuant to a single communication service. While contiguous time slots are sometimes available on other radio carriers, to date, particularly in an EDGE-based system, allocating time slots on different radio carriers is not permitted.  
      The elements of the communication stations  12  and  14  are functionally represented and are formed of functional elements, implementable in any desired manner. Additionally, while the functional elements are represented together, the physical locations at which the elements are formed need not be in common. For example, the elements shown to form portions of the network station  12  need not be positioned at a single physical location, e.g., at a base transceiver station of the network part. Rather, the elements of the network station, in one implementation, are distributed amongst more than one location, such as at the base transceiver station and at a base station controller. The network station includes a radio protocol stack  18  to which user application data is applied by way of the line  22 . The user application data is for communication to one or more mobile stations pursuant to one or more EDGE communication sessions. The radio protocol stack includes various logical layers including a radio resource management (RRM) layer.  
      The network station further includes a baseband element  24  to which data is provided, here represented by way of the lines  26 . The baseband element performs various baseband operations including baseband processing, modulation, and channel coding.  
      The network part also includes a radio element  28  to which the data is applied, here by way of the lines  32 . The radio element is formed, at least functionally, of radio frequency transceiver front ends  34 . N transceivers are shown in the figure, each of which is coupled to an antenna transducer  36  that transduces the data into electromagnetic form for communication to the mobile station, or stations  14 .  
      Pursuant to an embodiment of the present invention, the communication station  12  further includes a multi-carrier radio resource control logic element  42 . The element  42  is at least functionally coupled to the radio protocol stack  18 , represented by way of the lines  44  and  46 , to the baseband element  24 , here represented by way of the lines  48  and to the radio element  28 , here represented by way of the lines  52 . In the exemplary implementation, the element  42  is embodied at a radio resource management logical layer.  
      The multi-carrier radio resource control logic element includes an analyzer  54 , a resource allocator  56 , and an allocation message generator  58 . The analyzer  54  receives indications of the data that is to be communicated by the network part to a mobile station pursuant to effectuation of a communication service during a communication session. The indication of the characteristic comprises, for instance, the amount of data that is to be communicated, or some type of indicia that through analysis by the analyzer permits the communication requirements to communicate the data to be analyzed. Indications of the analysis performed by the analyzer are provided to the resource allocator. The resource allocator allocates resources based upon the analysis made by the analyzer together with indications of data scheduling information. The communication resource allocations are made across a plurality of logically-defined radio carriers according to a mobile allocation index offset scheme. In the exemplary implementation, a time slot and radio carrier, defined in terms of a mobile allocation index offset, combination is provided for each of the allocations. Depending upon the capabilities of the communication stations that are to be parties to the communication session in which the data is communicated to effectuate the communication service, the allocations include time slots allocated on different carriers at concurrent times. And, the number of radio carriers across which the allocations are made is also dependent upon the capabilities of the communication stations. For an allocation to be permitted, the communication stations must further be capable of communicating at the frequency of the radio carrier. The allocations made by the resource allocator are also dependent upon such criteria, indications of which are further applied to the radio resource control logic  42 .  
      Control messages are generated by the resource allocator and provided to the radio protocol stack, the baseband element, and the RF element to control their operation in conformity with the allocation of resources made by the allocator. An indication of the allocated resources is also provided to the allocation message generator  58 . The message generator generates an allocation message that is provided to one or more of the RF transceivers  34  of the RF element  28  for communication to the mobile station  14 . Through communication of the allocation message that contains values identifying the allocated resources, the mobile station is made aware of the allocated resources.  
      The mobile station includes structure analogous to structure of the network station. Here, the receive chain portion of the mobile station is shown. The mobile station includes an antenna transducer  64 , an RF element  66 , a baseband element  68 , and a radio protocol stack  74 . The RF element includes a plurality of RF transceivers  76  similar to the transceivers  34 , are operable at different carrier frequencies.  
      The mobile station also includes a multi-carrier radio resource control logic element  78  pursuant to an embodiment of the present invention. The element  78  includes a detector  82  and a controller  84 . And, the radio resource control logic element is coupled, at least functionally, to the radio protocol stack by way of the lines  86  and  88 , to the baseband element  92 , and to the RF transceivers of the RF element by way of the lines  94 . In the exemplary implementation, the element  78  is embodied at a radio resource management layer.  
      The detector  82  operates to detect the allocation message sent by the network station to the mobile station. The detector extracts values contained in the allocation message, or otherwise identifies the communication resources allocated to the communication session to communicate the data pursuant to effectuation of a communication service. Detections made by the detector are provided to the controller  84 . And, the controller operates to control operation of the mobile station so that the mobile station receives, and operates upon, the communicated data. The controller, for instance, controls operations of the various elements of the mobile station to ensure that the radio elements are operable at the proper times to receive the data communicated over the different carriers.  
       FIG. 2  illustrates a representation, shown generally at  122 , of communication resource allocations made for the communication of data pursuant to operation of an embodiment of the present invention. The representation illustrates three successive TDMA frames  124 ,  126 , and  128 , each of which includes eight time slots, numbered  0 - 7 . Eight radio frequency carriers  132 , identified as RF channels  1 - 8  of the inactive cell and carriers FM- 1 -FM-MAX of an adjacent cell all identify carriers identified in the exemplary communication system.  
      Here, the mobile station is capable of receiving data communicated on three RF carriers simultaneously. Communication resource allocations are made, therefore, with the constraint that the data be communicated upon no more than three carriers during any particular time slot. The references R 1 , R 2 , and R 3  are shown in the figure to identify the three carriers, defined logically according to an MAIO scheme, upon which data is communicated to the mobile station during any particular time slot. The indications T and M identify periods during which data is transmitted by the mobile station and during which measurements are made by the mobile station.  
      Resource allocations are made, by the allocator  56  shown in  FIG. 1 , to maximize the sum of downlink time slots allocated to a single mobile station given the constraint that the mobile station receive data on no more than three carriers during any single time slot while also observing the reaction times Tta, Ttb, Tra, and Trb, as defined in the TS 45.002 [2], Annex B specification. The reaction times, generally, identify the time required of a mobile station to get ready to transmit or receive, respectively, before receiving a subsequent burst, transmitting a subsequent burst, or performing a measurement on an adjacent-cell signal.  
      In the exemplary implementation, carrier/time slot combinations are selected in terms of an MAIO (Mobile Allocation Index Offset) and time slot combination by “scavenging” for available resources according to the following equation:  
         MAX   ⁢     :     ⁢       ∑     t   =   1     Nt     ⁢           ⁢       ∑     R   =   1     Nr     ⁢           ⁢       S   tR     ⁢     u   tR             ;     u   ∈     {     0   ,   1     }           
       St   ⁢     :     ⁢   u   ⁢     {               ⁢     a   =       1   ⋀     f   r       =         f     r   +   1       ⋁     (       f   m     =         f   r     ⋁     f   t       =     f   r         )       ⁢     :     ⁢   1                     Else   ⁢     :     ⁢   0           }         
 
 Where: 
 
 t=timeslot number 
 
 R=RF deck number (both transmit and receive) 
 
 Nt=Maximum number of timeslots in allocation 
 
 Nr=Maximum number of RF decks available for simultaneous reception in mobile terminal 
 
 S tR =Radio resource of timeslot “t” on RF deck “R” for mobile receiver 
 
 u tR =Utilization of timeslot “t” on RF deck “R” permitted according to the reaction time constraints (Boolean) 
 
 a=Timeslot availability for allocation to mobile downlink (Boolean) 
 
      Because the resources are not limited to those available upon a single carrier, a substantially increased possibility of availability of communication resources to effectuate communication of data is possible. As EDGE-based, as well as other types of, communication services are increasingly data-intensive, the increased availability of communication resources permits data to be communicated more quickly than that conventionally available.  
       FIG. 3  illustrates a method flow diagram, shown generally at  142 , representative of the method of operation of an embodiment of the present invention by which to communicate data between a set of communication stations in a communication scheme that provides for mobile allocation index offset or carrier frequency.  
      First, and as indicated by the block  144 , communication requirements required for the communication of the data are analyzed. The analysis is performed responsive to an indication of a characteristic of the data. Then, and as indicated by the block  146 , communication resources are allocated across a plurality of radio carriers for communication of the data.  
      Thereafter, and as indicated by the blocks  148  and  152 , an allocation message is generated and sent by a sending communication station to a receiving communication station that identifies allocations of the communication resources. And, as indicated by the block  154 , the allocation message is used at the receiving communication station to control its operation pursuant to communication of the data across the plurality of radio carriers.  
      Improved communication performance of a high-speed data service is thereby provided. Increased throughput rates relative to those achievable when resource allocations are limited to those of a single radio carrier is provided. Increasingly data-intensive data communication services are better able to be carried out without noticeable delay.  
      The previous descriptions are of preferred examples for implementing the invention, and the scope of the invention should not necessarily be limited by this description. The scope of the present invention is defined by the following claims.