Abstract:
An apparatus and a method for scheduling in consideration of a Service Connection Time Duration (SCTD) in a mobile communication system. The apparatus includes a User Equipment (UE) for transmitting a Media Access Control (MAC) Protocol Data Unit (PDU) including an SCTD measured by counting a connection time to receive an uplink service through a high speed data transmission, and a Base Transceiver Station (BTS) for receiving the MAC PDU including the SCTD from the UE, allocating a priority by considering the SCTD, and allocating radio resources based on the priority.

Description:
PRIORITY 
       [0001]    This application claims priority under 35 U.S.C. §119(a) to a Korean patent application filed in the Korean Intellectual Property Office on Aug. 10, 2007 and assigned Serial No. 2007-80435, the contents of which are incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates generally to an apparatus and a method for scheduling in consideration of a service connection time duration in a mobile communication system, and more particularly to an apparatus and a method for allocating priority of terminals using a service connection time duration received from the terminals and scheduling based on the priority when a Base Transceiver Station (BTS) allocates resources for an uplink service. 
         [0004]    2. Description of the Related Art 
         [0005]    Mobile communication systems are advancing to Third-Generation (3G) mobile communication systems of high speed and high quality to provide data service and multimedia service, beyond the more rudimentary voice-oriented services. The 3G mobile communication system represents a mobile telecommunication that supports not only the voice service but also a packet service, and employs a Code Division Multiple Access (CDMA) scheme. The 3G mobile communication system includes 3 rd  Generation Project Partnership (3GPP) or Universal Mobile Telecommunications System (UMTS) which is the standard in Europe and Japan based on asynchronization between the base transceiver stations (Node Bs), and 3GPP2 or CDMA2000 which is the standard in the United States of America, based on synchronization between Node Bs. 
         [0006]    The 3G mobile communication system, which is divided into the asynchronous system (3GPP) and the synchronous system (3GPP2), is standardizing for a radio data packet service of high quality. For example, the 3GPP is standardizing High Speed Downlink Packet Access (HSDPA) and the 3GPP2 is standardizing 1×EV-DV, which proves the effort on a solution for the high-speed and high-quality radio packet delivery over 2 Mbps in the 3G mobile communication system. 
         [0007]    The 3GPP also suggests the Enhanced Uplink Dedicated CHannel (EUDCH) to realize not only the rapid packet transmission from the BTS (Node B) to a User Equipment (UE) but also the radio packet transmission from the UE to the BTS. 
         [0008]    The BTS schedules the uplink for the rapid packet transmission by receiving a MAC Protocol Data Unit (PDU) from the UE. 
         [0009]      FIG. 1  illustrates a conventional structure of the MAC PDU. The MAC-e PDU  100  includes a plurality of MAC-es PDUs. A MAC header of the MAC-e PDU  100  includes a Data Description Indicator (DDI)  102 , which is information relating to the MAC-es PDU, and Number of MAC-d PDUs (N)  104 . The 6-bit DDI  102  represents a logical channel, a MAC-d flow, and a size of the MAC-d PDU. The 6-bit N  104  represents the number of consecutive MAC-d PDUs having the same DDI value. 
         [0010]    When the MAC-e PDU  100  includes Scheduling Information (SI)  108  carrying scheduling information, the MAC header includes DDI 0  in 6-bit size of ‘11111’ to inform of the SI in the MAC-e PDU  100 . 
         [0011]    The SI  108 , which is the information for the scheduling of the BTS, represents an amount of system resource required by the UE using 18 bits. The SI  108  includes UE Power Headroom (UPH)  112 , Total Enhanced Dedicated Channel (E-DCH) Buffer Status (TEBS)  114 , Highest priority Logical channel Buffer Status (HLBS)  116 , and Highest priority Logical channel ID (HLID)  118 . 
         [0012]    The 5-bit UPH  112  indicates a ratio or a DPCCH code power to a maximum transmit power of the UE, the 5-bit TEBS  114  indicates an amount of data of all logical channels mapped to the E-DCH, and the 4-bit HLBS  116  indicates an amount of data of the logical channel indicated by the HLID, and the 4-bit HLID  118  is an ID of the highest-priority logical channel among the data available in the buffer. More detailed descriptions about the MAC-e PDU of  FIG. 1  are provided in the Specification “3GPP TS 25.321 (Release 6)”. 
         [0013]    The BTS differentiates the network resource allocation per UE using the SI  108  received from the UE. Particularly, the BTS preferentially schedules based on the HLID  118 . That is, the BTS discriminates the resource allocation preferentially based on the service type. The UEs in the uplink service through the high-speed data transmission use almost the same service such as File Transfer Protocol (FTP) or Video On Demand (VOD). In the similar network environment, the UEs are assigned the equal scheduling weight from the BTS and are allocated similar network resources. Hence, when the resource reaches the limit because of a maximum amount of users in the uplink service through the high-speed data transmission, there is a problem in that the BTS is likely to equally schedule the UEs of the same service. 
       SUMMARY OF THE INVENTION 
       [0014]    The present invention has been designed to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present invention is to provide an apparatus and a method for scheduling in consideration of a service connection time duration in a mobile communication system. 
         [0015]    Another aspect of the present invention is to provide an apparatus and a method for allocating priority of UEs using a service connection time duration received from the UEs and scheduling based on the priority when a BTS allocates resources for an uplink service in a mobile communication system. 
         [0016]    Another aspect of the present invention is to provide an apparatus and a method for a UE to be scheduled by a BTS in consideration of a service connection time duration after the UE in an uplink service measures and sends the service connection time duration in a mobile communication system. 
         [0017]    Another aspect of the present invention is to provide a structure of a Media Access Control (MAC) Protocol Data Unit (PDU) including information relating to a service connection time duration to schedule based on the service connection time duration in a mobile communication system. 
         [0018]    The above aspects are achieved by providing an apparatus for scheduling in consideration of a Service Connection Time Duration (SCTD) in a mobile communication system including a UE for transmitting a MAC PDU having an SCTD measured by counting a connection time to receive an uplink service through a high speed data transmission, and a BTS for receiving the MAC PDU having the SCTD from the UE, allocating a priority by considering the SCTD, and allocating radio resources based on the priority. 
         [0019]    According to the present invention, a UE for receiving an uplink service in consideration of a SCTD includes an SI checker for checking SI indicative of an amount of system resource required by the UE, an SCTD checker for measuring the SCTD which is an uplink service time through a high speed data transmission, and a PDU generator for generating a MAC PDU having the SI and the SCTD, when detecting a MAC PDU generation event. 
         [0020]    According to the present invention, a BTS for providing an uplink service in consideration of a SCTD includes an SI extractor for extracting SI by checking whether a received MAC PDU includes the SI, an SCTD extractor for extracting an SCTD by checking whether the received MAC PDU includes SCTD information, and a scheduler for scheduling a priority for an uplink service of a UE in consideration of the SI and the SCTD and allocating radio resources based on the priority. 
         [0021]    According to the present invention, a method for a UE to receive an uplink service in consideration of a SCTD includes checking SI indicative of an amount of system resource required by the UE when detecting a MAC PDU generation event, measuring the SCTD which is an uplink service time through a high speed data transmission, and generating a MAC PDU including the SI and the SCTD. 
         [0022]    According to the present invention, a method for a BTS to provide an uplink service in consideration of an SCTD includes extracting SI by checking whether a received MAC PDU includes the SI, extracting an SCTD by checking whether the received MAC PDU includes SCTD information, scheduling a priority for an uplink service of a UE in consideration of the extracted SI and the extracted SCTD, and allocating radio resources based on the priority. 
         [0023]    Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses preferred embodiments of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    The above and other aspects, features and advantages of certain exemplary embodiments the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: 
           [0025]      FIG. 1  illustrates a conventional structure of a MAC PDU; 
           [0026]      FIG. 2  illustrates a structure of a MAC PDU according to the present invention; 
           [0027]      FIG. 3  illustrates a mobile communication system for scheduling an uplink service in consideration of a service connection time duration according to the present invention; 
           [0028]      FIG. 4  illustrates a method for a UE to be scheduled in an uplink service in consideration of the service connection time duration according to the present invention; and 
           [0029]      FIG. 5  illustrates a method for a BTS to schedule in consideration of the service connection time duration according to the present invention. 
       
    
    
       [0030]    Throughout the drawings, like reference numerals will be understood to refer to like parts, components and structures. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0031]    The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of preferred embodiments of the present invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely preferred. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. Also, descriptions of well-known functions and constructions are omitted for the sake of clarity and conciseness. 
         [0032]    Preferred embodiments of the present invention provide an apparatus and a method for allocating priority of UEs using a service connection time duration of the UEs and scheduling based on the priority when a BTS allocates resources for an uplink service in a mobile communication system. 
         [0033]      FIG. 2  illustrates a structure of the MAC PDU according to the present invention. A MAC header of a MAC-e PDU  200  includes a Data Description Indicator (DDI −1 )  202  of the value ‘111110’ to indicate that the MAC-e PDU  200  includes SCTD information. Specifically, when the MAC-e PDU  200  includes the SCTD information, the MAC header uses DDI −1    202 . When the MAC-e PDU  100  does not include the SCTD information but includes only SI  108 , the MAC header uses DDI 0    106 . 
         [0034]    In addition to the conventional UE Power Headroom (UPH)  112 , Total E-DCH Buffer Status (TEBS)  114 , Highest priority Logical channel Buffer Status (HLBS)  116  and Highest priority Logical channel ID (HLID)  118 , the SI  210  of the present invention includes 12-bit SCTD information  212  indicative of uplink SCTD information of a UE. 
         [0035]      FIG. 3  illustrates a mobile communication system for scheduling an uplink service in consideration of a service connection time duration according to the present invention. The mobile communication system of  FIG. 3  includes a UE  300  for transmitting a MAC PDU in the uplink service by including the service connection time duration, and a BTS  350  for scheduling based on the received SCTD upon receiving the MAC PDU including the SCTD. 
         [0036]    The UE  300  includes a controller  302 , a buffer  304 , a communicator  306 , a padding bit checker  308 , an SI checker  310 , an SCTD checker  312  and a PDU generator  314 . 
         [0037]    The buffer  304  temporarily stores data transmitted for the uplink service. In the reception, the communicator  306  down-converts a Radio Frequency (RF) signal received via an antenna, despreads and channel-decodes the received signal. In the transmission, the communicator  306  channel-codes and spreads data, up-converts the data and transmits the data via the antenna. In the uplink service, the communicator  306  transmits a MAC PDU generated at the PDU generator  314  to the BTS  350 . 
         [0038]    The padding bit checker  308  checks a size of padding bits, which pad a fixed-length block or an unused area of a record with specific information. 
         [0039]    The SI checker  310  checks SI relating to the amount of system resource required by the UE  300  for the sake of the scheduling of the uplink service at the BTS  350 . The SI is 18-bit information including UPH, TEBS, HLBS and HLID. 
         [0040]    The SCTD checker  312  measures an SCTD which is the time taken for the UE  300  to communicate with the BTS  350  and to receive the uplink service through the rapid data transmission. The SCTD is 12 bits in size. The SCTD increases by 1 per 2560 ms. The countable time of the SCTD is up to about 3 hours. When the uplink service starts, the SCTD checker  312  generates the SCTD information. When a certain time elapses in the course of the uplink service, the SCTD checker  312  updates the SCTD information. When the uplink service ends, the SCTD checker  312  deletes the SCTD information. 
         [0041]    The count of the SCTD in systems having different data rates is represented as shown in Table 1. 
         [0000]    
       
         
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 System type 
                 Count 
               
               
                   
               
             
             
               
                 10 ms TTI system  
                 Increase by 1 per 256 × TTI (=2560 ms) 
               
               
                   
                 starting from SCTD 
               
               
                 2 ms TTI system 
                 Increase by 1 per 1280 × TTI (=2560 ms) 
               
               
                   
                 starting from SCTD 
               
               
                 1 ms TTI system 
                 Increase by 1 per 2560 × TTI (=2560 ms) 
               
               
                   
                 starting from SCTD 
               
               
                   
               
             
          
         
       
     
         [0042]    Upon detecting a MAC PDU generation event, the PDU generator  314  includes data to the MAC PDU through the padding bit checker  308  and checks a size of the padding bits which is a spare area. When the padding bits exceeds 36 bits; that is, when the padding bits can include all of the SI, the SCTD information, and the DDI informing of the use of the SCTD information, the PDU generator  314  includes the SI confirmed at the SI checker  310  and the SCTD information measured at the SCTD checker  312  into the MAC PDU, includes DDI −1  informing that the MAC PDU includes the SI and the SCTD information into the MAC header, and then controls the communicator  306  to transmit the generated MAC PDU to the BTS  350 . The structure of the MAC PDU is illustrated in  FIG. 2 . 
         [0043]    By contrast, when the size of the padding bits confirmed at the padding bit checker  308  does not exceed 36 bits, the PDU generator  314  generates a MAC PDU in the conventional manner. More specifically, when the size of the padding bits is less than 18 bits, the PDU generator  314  generates a MAC PDU not including SI, SCTD information and DDI information. When the size of the padding bits is between 18 bits and 24 bits, the PDU generator  314  generates a MAC PDU including the SI. When the size of the padding bits is between 24 bits and 36 bits, the PDU generator  314  generates a MAC PDU including the SI and the DDI 0 . 
         [0044]    The controller  302  controls the padding bit checker  308 , the SI checker  310 , the SCTD checker  312  and the PDU generator  314 . In other words, the controller  302  can function as the padding bit checker  308 , the SI checker  310 , the SCTD checker  312  and the PDU generator  314 . Herein, the checkers are separately provided to distinguish their functions. In the actual implementation, the controller  302  may process all or part of the functions of the padding bit checker  308 , the SI checker  310 , the SCTD checker  312  and the PDU generator  314 . 
         [0045]    The BTS  350  includes a controller  352 , a buffer  354 , a communicator  356 , an SI extractor  358 , an SCTD extractor  360  and a scheduler  362 . 
         [0046]    The buffer  354  temporarily stores MAC PDUs received from the UEs. In the reception, the communicator  356  down-converts an RF signal received via an antenna, and despreads and channel-decodes the received signal. In the transmission, the communicator  356  channel-codes and spreads data, up-converts the data, and then transmits the data via the antenna. In the uplink service, the communicator  356  receives the MAC PDU including the SCTD information from the UE. 
         [0047]    Upon receiving the MAC PDU from the UE through the communicator  356 , the SI extractor  358  checks whether the received MAC PDU includes SI. When the MAC PDU includes the SI, the SI extractor  358  extracts the SI and provides the extracted SI to the scheduler  362 . 
         [0048]    The SCTD extractor  360  checks whether the received MAC PDU includes SCTD information. When the MAC PDU includes the SCTD information, the SCTD extractor  360  extracts and provides the SCTD to the scheduler  362 . 
         [0049]    The scheduler  362  schedules priority of the UEs for their uplink service and allocates radio resources based on the priority by considering the scheduling information of the UEs extracted at the SI extractor  358  and the SCTDs of the UEs extracted at the SCTD extractor  360 . The scheduler  362  gives a high priority for the low SCTD and gives a low priority for the high SCTD. 
         [0050]    The controller  352  controls and functions as the SI extractor  358 , the SCTD extractor  360  and the scheduler  362 , which are separately provided to distinguish their functions. In the actual implementations, the controller  352  may process all or part of the functions of the SI extractor  358 , the SCTD extractor  360  and the scheduler  362 . 
         [0051]      FIG. 4  is a flowchart illustrating a method for a UE to be scheduled in an uplink service in consideration of the service connection time duration according to the present invention. When detecting a MAC PDU generation event in step  400 , the UE checks data to be included to the MAC PDU in step  402 , checks the size of the padding bits which is a spare area after including the data of the MAC PDU in step  404 , and checks whether the padding bits exceed 36 bits in step  406 . When the size of the padding bits is less than 36 bits in step  406 , the UE generates a MAC PDU in the conventional manner. 
         [0052]    When the size of the padding bits exceeds 36 bits in step  406 , the UE checks SI represented using the UPH, the TEBS, the HLBS and the HLID in step  408 , and checks the SCTD in step  410 . The SCTD is 12 bits in size and measured by increasing by 1 at time intervals (e.g., per 2560 ms) starting from the service connection. In step  412 , the UE includes the SI and the SCTD information to the MAC PDU and includes DDI −1  informing of the SI and the SCTD information to the header of the MAC PDU. In step  414 , the UE transmits the generated MAC PDU to the BTS. 
         [0053]      FIG. 5  illustrates a method for a BTS to schedule in consideration of the SCTD according to the present invention. 
         [0054]    When receiving the MAC PDU from the UE in step  500 , the BTS checks whether the received MAC PDU includes SI in step  502 . When the SI is not included, the procedure goes to step  510 . 
         [0055]    When the MAC PDU includes the SI in step  502 , the BTS extracts the SI from the received MAC PDU in step  504  and checks whether the received MAC PDU includes SCTD information in step  506 . When no SCTD information is included, the procedure goes to step  510 . 
         [0056]    When the SCTD information is included, the BTS extracts the SCTD from the received MAC PDU in step  508 , and schedules the priority of the uplink service of the UE by considering the extracted SI and the SCTD in step  510 , and then allocates radio resources based on the priority in step  512 . 
         [0057]    In step  510 , the BTS gives a high priority to the low SCTD and gives a low priority to a high SCTD. 
         [0058]    As set forth above, in the mobile communication system, the UE transmits the MAC PDU including the SCTD which counts the connection time to receive the downlink service through the high speed data transmission, and the BTS receives the MAC PDU including the SCTD information from the UE, allocates the priority based on the SCTD, and schedules to allocate the radio resources based on the priority. Therefore, users can be serviced with a fair priority based on the SCTD. 
         [0059]    While the present invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims and their equivalents.