Abstract:
A method of providing a packetized data transmission service to a mobile terminal ( 108 ) in a spread spectrum communication network ( 100 ), includes: at a transmitter ( 102 ), broadcasting an indication message to a cell on a downlink broadcast channel ( 114 ), the indication message providing notification of an available packetized data transmission service intended for the mobile terminal ( 108 ); at the mobile terminal ( 108 ), monitoring the broadcast channel ( 114 ) for the indication message, and upon receipt, acknowledging detection of the indication message to the transmitter ( 102 ) on an uplink contention channel ( 116 ); and at the transmitter ( 102 ), upon contention completion, transmitting packetized data transmission service configuration information to the mobile terminal ( 108 ) on the broadcast channel ( 114 ).

Description:
CROSS REFERENCE 
     This application is a Divisional of U.S. patent application Ser. No. 12/064,796, filed Feb. 25, 2008, and is a national phase application under 35 U.S.C. §371 of International Patent Corporation Treaty Application No. PCT/JP06/317148, filed Aug. 24, 2006, which claims priority to Australian Patent Application No. 2005904679, filed Aug. 26, 2005. The contents of each of these referenced applications is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to the provision of downlink packet access services to a mobile station in a spread spectrum communication network. The invention is suitable for use in the provision of such services to a user equipment in a communication network conforming to the 3GPP-LTE standards being developed by the 3rd Generation Partnership Project (3GPP), and it will be convenient to describe the invention in relation to this exemplary, but non-limiting, application. 
     PRIOR ART 
     Recent enhancements in packet transmissions such as High Speed Downlink Packet Access (HSDPA) and enhanced uplink technology have made 3GPP radio-access technology highly competitive. In order to ensure that the competitiveness of this technology continues over a long time frame, a long term evolution of 3GPP radio-access technology is being developed. This new technology is known as Super 3G 
     Important parts of the long term evolution of Super 3G technology will include Radio Access Network (RAN) latency reduction, higher user data rates, improving system capability and coverage, and reducing cost to a network operator. In order to achieve this, an evolution of the radio interface as well as the radio network architecture is being considered. The objective of this evolution is to develop a framework to enable high data rate, low-latency and packet-optimized radio-access. 
     Development of the Super 3G system has been focused on supporting services provided by the PS-domain, such as enhanced HSDPA, Multimedia Broadcast Multicast Services (MBMS), High Speed Uplink Packet Access (HSUPA) and other similar types of packet-switched services including Voice Over IP. 
     Existing HSDPA services in Wideband Code Division Multiple Access (WCDMA) systems are currently provided in a manner that is dependent on other dedicated RAN services. This results in an extremely complicated protocol stack design, and hinders the development of HSDPA services in WCDMA. 
     The Super 3G system will be developed to support enhanced HSDPA and other types of packet-switched services. However, reusing the existing HSDPA-related procedures that have been developed for the WCDMA system will lead to a situation where the future 3G system shall be coupled with and operationally dependent on existing WCDMA technology. This interdependence is likely to result in an even more complicated RAN architecture, which will then increase the cost of design, manufacture and operation of the Super 3G system. 
     There therefore exists a need to enable enhanced HSDPA services to be introduced into the future Super 3G system in such a manner as to be able to operate independently from the existing 3G-WCDMA system when considered from the RAN perspective. There also exists a need to provide enhanced HSDPA services in a manner that ameliorates or overcomes HSDPA service provision techniques. 
     DISCLOSURE OF THE INVENTION 
     In one aspect of the present invention, there is provided a method of providing a packetized data transmission service to a mobile terminal in a spread spectrum communication network, the method including at a base station, broadcasting an indication message to a cell on a downlink broadcast channel, the indication message providing notification of an available packetized data transmission service intended for the mobile terminal, at the mobile terminal, monitoring the broadcast channel for the indication message, and upon receipt, acknowledging detection of the indication message to the base station on an uplink contention channel, and at the base station, upon contention completion, transmitting packetized data transmission service configuration information to the mobile terminal on the broadcast channel. 
     The method may further include the steps of periodically placing the mobile terminal in an active state to monitor the broadcast channel for the indication message, and placing the mobile terminal in an inactive state, if no indication message is detected. 
     The method may further include the step of at the base station, transmitting control information for the packetized data transmission service to the mobile terminal on a downlink shared control channel. 
     The method may further include the step of at the base station, transmitting data for the packetized data transmission service to the mobile terminal on a downlink shared data channel. 
     The method may further include the step of at the mobile terminal, transmitting channel quality measurement and reporting information to the base station on an uplink shared scheduled channel. 
     The method may further include the steps of ceasing transmission from the base station of packetized data transmission control information to the mobile terminal, and upon failure to detect the packetized data transmission control information at the mobile terminal within a predetermined time, terminating the packetized data transmission service. 
     The method may further include the steps of at the base station, notifying the mobile terminal to terminate the packetized data transmission service by inclusion of a termination message in a packet header of an packetized data transmission control information packet, and upon detection of the termination message at the mobile terminal, terminating the packetized data transmission service. 
     For instance, the mobile terminal is comprised of a mobile phone. 
     In another aspect of the present invention, there is provided a method of controlling an operation of a base station for providing a packetized data transmission service to a mobile terminal in a spread spectrum communication network, the method including broadcasting an indication message to a cell on a downlink broadcast channel, the indication message providing notification of an available packetized data transmission service intended for the mobile terminal, the mobile terminal monitoring the broadcast channel for the indication message, and upon receipt, acknowledging detection of the indication message to the base station on an uplink contention channel, and upon contention completion, transmitting packetized data transmission service configuration information to the mobile terminal on the broadcast channel. 
     The method may further include the step of transmitting control information for the packetized data transmission service to the mobile terminal on a downlink shared control channel. 
     The method may further include the step of transmitting data for the packetized data transmission service to the mobile terminal on a downlink shared data channel. 
     The method may further include the steps of ceasing transmission of packetized data transmission control information to the mobile terminal, and upon failure to detect the packetized data transmission control information at the mobile terminal within a predetermined time, terminating the packetized data transmission service. 
     The method may further include the steps of notifying the mobile terminal to terminate the packetized data transmission service by inclusion of a termination message in a packet header of an packetized data transmission control information packet, and upon detection of the termination message at the mobile terminal, terminating the packetized data transmission service. 
     In still another aspect of the present invention, there is provided a program for causing a computer equipped in a base station to carry out the above-mentioned method. 
     In yet another aspect of the present invention, there is provided a system for providing a packetized data transmission service in a spread spectrum communication network, the system including a base station and a mobile terminal, the base station being adapted to broadcast an indication message to a cell on a downlink broadcast channel, the indication message providing notification of an available packetized data transmission service intended for the mobile terminal, the mobile terminal being adapted to monitor the broadcast channel for the indication message, and upon receipt, acknowledging detection of the indication message to the base station on an uplink contention channel, and the base station being further adapted, upon contention completion, to transmit packetized data transmission service configuration information to the mobile terminal on the broadcast channel. 
     In the above-mentioned system, the mobile terminal may be comprised of a mobile phone. 
     In still yet another aspect of the present invention, there is provided a base station in a system for providing a packetized data transmission service in a spread spectrum communication network, the system including the base station and a mobile terminal, the base station being adapted to broadcast an indication message to a cell on a downlink broadcast channel, the indication message providing notification of an available packetized data transmission service intended for the mobile terminal, the mobile terminal being adapted to monitor the broadcast channel for the indication message, and upon receipt, acknowledging detection of the indication message to the base station on an uplink contention channel, and the base station being further adapted, upon contention completion, to transmit packetized data transmission service configuration information to the mobile terminal on the broadcast channel. 
     The present invention will now be described in reference to the attached drawings in which a method and system of providing a High Speed Downlink Packet Access (HSDPA) service is illustrated as a preferred embodiment. It is to be appreciated that the invention is not to be construed as being limited to the particular embodiment illustrated in the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram illustrating a spread spectrum communication system in which an HSDPA service is provided from a base transceiver station to a user equipment. 
         FIGS. 2A and 2B  comprise a timing diagram illustrating the functional steps performed at both the base transceiver station and the user equipment during notification, acknowledgement, performance and termination of the HSDPA service. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Preferred embodiments in accordance with the present invention will be explained herein below with reference to drawings. 
     Referring now to  FIG. 1 , there is shown generally a spread spectrum communication network  100  including a base transceiver station (BTS)  102  operably connected to a radio transmission tower  104 , and a user equipment (UE)  108 . 
     For instance, the user equipment  108  is comprised of a mobile phone. 
     The base transceiver station (BTS)  102  and the radio tower  104  are operably connected to a communication network (Super 3G network)  106  conforming to the Super 3G system being developed by the 3GPP. 
     The base transceiver station  102  communicates with the user equipment  108  whilst the user equipment  108  is located within a broadcast cell  110 . Control information and data is exchanged between the base transceiver station  102  and the user equipment  108  during the provision of High Speed Downlink Packet Access (HSDPA) services by means of a channel structure  112  including a downlink (DL) broadcast channel  114 , an uplink (UL) reserved channel (contention)  116 , a downlink (DL) shared control channel  118 , a downlink (DL) shared data channel  120 , and an uplink scheduled channel (shared control channel and physical control channel)  122 . 
     For instance, the base transceiver station  102  includes a central processing unit (CPU), a first memory, a second memory, an input interface through which a command and/or data is input into the central processing unit, an output interface through which a result of steps having been executed by the central processing unit is output, and a bus through which the central processing unit is electrically connected with the first memory, the second memory, the input interface, and the output interface. 
     Each of the first and second memories and is comprised of a semiconductor memory such as a read only memory (ROM), a random access memory (RAM) or an IC memory card, or a storage device such as a flexible disc, a hard disc or an optic magnetic disc. 
     For instance, the first memory comprises a read only memory (ROM), and the second memory comprises a random access memory (RAM). 
     The first memory stores therein a program for causing the central processing unit to carry out a method of controlling an operation of the base transceiver station  102  for providing a packetized data transmission service to the user equipment  108  in a spread spectrum communication network. The second memory stores therein various data and parameters, and presents a working area to the central processing unit. The central processing unit reads the program out of the first memory, and executes the program. Thus, the central processing unit operates in accordance with the program stored in the first memory. 
     Referring now to  FIGS. 2A and 2B , when the user equipment  108  moves within the broadcast cell  110 , both the base transceiver station  102  and the user equipment  108  act at step  200  to allow the user equipment  108  to register with the Super 3G network  106  and thereby enable the base transceiver station  102  to communicate directly with the user equipment  108 . 
     At step  202 , the base transceiver station  102  transmits synchronization information to the user equipment  108  on a synchronization channel/common pilot channel in order for the user equipment  108  to detect relevant information sent to the user equipment  108  in data packets. 
     Upon receipt of the synchronization information at step  202 , the user equipment  108  performs, at step  204 , cell search, frame timing detection, symbol timing, and scrambling code detection functions in accordance with conventional WCDMA techniques to enable communication to be established between the Super 3G network  106  and the user equipment  108 . 
     When an HSDPA service is to be provided to the user equipment  108 , an indication message is prepared at step  206  to be broadcast to the entire cell  110 , the indication message being encoded in such way that it can be decoded and identified by the user equipment  108  by a specific user equipment identification number that is allocated to the user equipment  108  by the Super 3G network  106  at step  200 . The indication message acts to notify the user equipment  108  of an available HSDPA services intended for the user equipment  108 . 
     The encoded information is then broadcast at step  208  on the downlink broadcast channel  114  (set of sub-carriers), the user equipment  108  being informed of the downlink broadcast channel  114  upon registration with the Super 3G network  106  at step  200 . 
     At step  210 , the user equipment  108  is normally in an inactive (sleep) state, except for predetermined periods of time when, in step  212 , the user equipment  108  is placed in an active (wake-up) state in order to monitor the downlink broadcast channel  114  for indication messages transmitted from the base transceiver station  102 . 
     If no indication message is detected, the user equipment  108  is once again placed in an inactive state. 
     However, if an indication message is detected, the user equipment  108  processes the indication message, and transmits an acknowledgement  214  of detection of the indication message to the base transceiver station  102  on the uplink reserved channel  116  using a contention approach. The uplink reserved channel information on which the acknowledgement  214  is transmitted is indicated to the user equipment  108  in the indication message. 
     The base transceiver station  102  monitors the uplink reserved channel  116  at step  216  for the acknowledgement  214 . 
     Upon receipt of the acknowledgement  214  from the user equipment  108 , the base transceiver station  102  informs the user equipment  108  about the contention completion, and starts to prepare and transmit the RAN HSDPA service configuration information  218  on the downlink broadcast channel  114 , at a time and frequency allocated for this task. This downlink broadcast channel  114  is monitored only by the user equipment(s)  108  that previously sent an acknowledgement  214  to the indication message. 
     Upon successful completion of the contention, the user equipment  108  prepares to receive data on the downlink broadcast channel  114  at a predetermined time after completion of the contention, at step  220 . The configuration information received on this channel assists the user equipment  108  to perform layer 1 (physical layer), layer 2 (medium access control/radio link control), and layer 3 (Radio Resource Control layer) configuration to monitor the downlink shared control channel  118 , configuring the Hybrid Automatic Repeat Request (HARD) related functions and performing channel quality measurement and reporting. 
     Once the configuration has taken place at step  220 , the user equipment  108  starts performing, at step  222 , channel quality measurement, and monitoring of the downlink shared control channel  118  to detect fast signaling intended for the user equipment  108  and other existing HSDPA related procedures for receiving data on the downlink shared data channel  120 . 
     Accordingly, channel quality information (CQI)  224  is transmitted from the user equipment  108  to the base transceiver station  102  according to a preconfigured schedule in order to provide the base transceiver station  102  with information as to which frequency chunk in the downlink shared data channel  120  is best suited for the particular user equipment  108  in order that frequency scheduling can be optimized. 
     The channel quality information  224  is transmitted on the uplink scheduled channel  122 . Once the base transceiver station  102  has received initial channel quality information  224 , the base transceiver station  102 , at step  226 , performs channel scheduling and sends fast signaling information  228  on the downlink shared control channel  118  to the user equipment  108 . 
     The associated packet data  230  is then sent on the downlink shared data channel  120  to the user equipment  108 . At step  232 , the user equipment  108  keeps monitoring the downlink shared control channel  118  on the allocated time-frequency slot. 
     Once the user equipment  108  detects control information intended for that user equipment  108 , the user equipment  108  starts to receive and decode the associated packet data  230  transmitted on the downlink shared data channel  120 . 
     The result of the data packet reception (ACK/NACK/POST/PRE/DTX for H-ARQ processing)  234  is then reported to the base transceiver station  102  on the associated uplink scheduled channel  122 . 
     Similarly, the channel quality information (CQI)  236  for the downlink packet scheduling is again transmitted on the uplink scheduled channel  122 . 
     At step  238 , once the H-ARQ feedback information and channel quality information has been received, the base transceiver station  102  performs Adaptive Modulation and Coding (AMC), scheduling and retransmission for each user equipment  108 . Retransmission occurs if a NACK message is received from the user equipment  108 . 
     The above-mentioned steps  228  to  238  are then repeated at both the base transceiver station  102  and the user equipment  108  during provision of the HSDPA service to the user equipment  108 . 
     Once the HSDPA service provided to the user equipment  108  is to be terminated, the base transceiver station  102  may simply stop transmission of control information on the downlink shared control channel  118  to the user equipment  108 , at step  240 . 
     In this case, upon failure of the user equipment  108  at step  242  to detect HSDPA control information within a predetermined time, the HSDPA service is terminated and the user equipment  108  is again placed in an inactive state. 
     Alternatively, the HSDPA service can be terminated by inclusion of the termination message in a packet header of an HSDPA control information packet sent to the user equipment  108  on the downlink shared data channel  120 . Upon detection of the termination message at the user equipment  108 , the HSDPA service may be terminated. 
     From the foregoing, it will be appreciated that the above-described method for providing an HSDPA service to a user equipment advantageously introduces a specific paging procedure and specific paging indication for an HSDPA service without requiring use of a dedicated data channel as currently described in WCDMA networks. 
     Moreover, the above-described method introduces a sleep mode to allow the Super 3G user equipment to save power when in use. A new channel is introduced to establish the Radio Resource Control (RRC) layer peer to peer communication for HSDPA RAN configuration, rather than relying upon a dedicated channel as in current WCDMA systems. 
     A packet transmission termination scheme is also introduced at the radio interface level to allow either the base transceiver station  102  to terminate a downlink packet transmission either temporarily or permanently whilst minimizing the exchange of traffic via the air interface between the base transceiver station  102  and the user equipment  108 . 
     Finally, it is to be appreciated that various modifications and additions may be made to the above-described method of providing a high speed downlink packet access service to a user equipment in the spread spectrum communication network without departing from the spirit or ambit of the invention.