Patent Publication Number: US-11026287-B2

Title: Method and apparatus for selectively enabling reception of downlink signaling channels

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 15/824,278 filed Nov. 28, 2017, which is a continuation of U.S. patent application Ser. No. 14/871,130 filed Sep. 30, 2015, now U.S. Pat. No. 9,867,288 which issued on Jan. 9, 2018, which is a continuation of U.S. patent application Ser. No. 14/063,430, filed Oct. 25, 2013, which is abandoned, which is a continuation of U.S. patent application Ser. No. 11/095,401, filed Mar. 31, 2005, which issued on Oct. 29, 2013 as U.S. Pat. No. 8,570,952, which claims the benefit of U.S. Provisional Application No. 60/566,620 filed Apr. 29, 2004, which are incorporated by reference as if fully set forth. 
    
    
     FIELD OF INVENTION 
     The present invention is related to a wireless communication system including a wireless transmit/receive unit (WTRU) and at least one Node-B. More particularly, the present invention is a method and apparatus for selectively enabling reception of downlink (DL) enhanced uplink (EU) signaling channels established between the WTRU and the Node-B(s). 
     BACKGROUND 
     Methods for improving uplink (UL) coverage, throughput and transmission latency are being investigated in Release 6 (R6) of the 3rd Generation Partnership Project (3GPP). In order to successfully implement these methods, the scheduling and assigning of UL radio resources have been moved from a radio network controller (RNC) to a Node-B such that the Node-B can make decisions and manage UL radio resources on a short-term basis more efficiently than the RNC, even if the RNC retains overall control over the Node-B. 
     EU operation requires transmitting information such as UL channel allocations and transmission feedback information to the WTRU via DL EU signaling channels. The WTRU monitors the DL EU signaling channels for the reception of channel allocations and transmission feedback information. 
     A method and apparatus is desired for controlling reception of the DL EU signaling channels such that they are enabled only when required. 
     SUMMARY 
     The present invention is a method and apparatus for selectively enabling reception of at least one DL EU signaling channel used for EU operation. During the operation of an enhanced dedicated channel (E-DCH), a WTRU monitors at least one DL EU signaling channel established between the WTRU and at least one Node-B only when it is necessary, based on the WTRU&#39;s knowledge of at least one established standard procedure. The WTRU coordinates and consolidates DL signaling channel reception requirements of a plurality of channel allocation and/or data transmission procedures carried out by the WTRU in accordance with the established standard procedure. The WTRU determines whether to enable reception of at least one specific DL signaling channel based on the consolidated DL signaling channel reception requirements. 
     In accordance with the present invention, the WTRU does not have to continuously enable the reception of the DL EU signaling channel during EU operation. Instead, the WTRU may selectively turn on and off, (i.e., enable and disable), reception of at least one specific DL EU signaling channel, thus reducing WTRU processing requirements and reducing the probability of misinterpretation of DL signaling. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more detailed understanding of the invention may be had from the following description of a preferred example, given by way of example and to be understood in conjunction with the accompanying drawing wherein: 
         FIG. 1  is a block diagram of a wireless communication system operating in accordance with the present invention; 
         FIG. 2  is a flow diagram of a process including method steps for selectively enabling reception of at least one DL EU signaling channel during EU operation when the WTRU sends an EU channel allocation request and is expecting to receive scheduling information in accordance with one embodiment of the present invention; and 
         FIG. 3  is a flow diagram of a process including method steps for selectively enabling reception of at least one DL EU signaling channel when the WTRU sends E-DCH data and is expecting to receive feedback information in accordance with another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S) 
     Hereafter, the terminology “WTRU” includes but is not limited to a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, or any other type of device capable of operating in a wireless environment. When referred to hereafter, the terminology “Node-B” includes but is not limited to a base station, a site controller, an access point or any other type of interfacing device in a wireless environment. 
     The features of the present invention may be incorporated into an integrated circuit (IC) or be configured in a circuit comprising a multitude of interconnecting components. 
       FIG. 1  is a block diagram of a wireless communication system  100  operating in accordance with the present invention. The system  100  includes a WTRU  102 , at least one Node-B  104  and an RNC  106 . The WTRU  102  includes an E-DCH data buffer  112 , a physical reception control entity  114 , a receiver  116 , a transmitter  118 , a processor  120  and a standards database  122 . 
     The transmitter  118  in the WTRU  102  transmits an EU channel allocation request, (i.e., a rate request), to the Node-B(s)  104  through a UL EU channel  108  for EU transmission to the Node-B  104 . The EU channel allocation request may include scheduling information. The scheduling information may include traffic volume measurement (TVM) information of E-DCH data stored in the buffer  112  of the WTRU  102  and available EU transmit power information. 
     After the EU channel allocation request is transmitted, the receiver  116  in the WTRU  102  monitors a plurality of DL EU signaling channels  110   1 ,  110   2 , . . . ,  110   N  for channel allocation information via the physical reception control entity  114 . The Node-B(s)  104  responds to the EU channel allocation request with UL channel allocation information through one of the DL EU signaling channels  110   1-N . 
     The system  100  is configured such that both UL signaling and E-DCH data are transmitted from the WTRU  102  to the Node-B(s)  104  via the UL EU channel  108 . After receiving scheduling information for channel allocation from the Node-B(s)  104  through at least one of the DL EU signaling channels  110   1-N , the transmitter  118  in the WTRU  102  transmits E-DCH data through the allocated UL EU channel  108 . The receiver  116  in the WTRU  102  then monitors the DL EU signaling channel(s)  110   1-N  for expected E-DCH data feedback information. 
     In response to receiving the E-DCH data, the Node-B(s)  104  transmits E-DCH data feedback information to the WTRU  102  through the DL EU signaling channels  110   1-N . The feedback information includes either a positive acknowledgement (ACK) message or a negative acknowledgement (NACK) message, depending on the success or failure of the Node-B(s)  104  decoding the E-DCH data sent over the UL EU channel  108  by the WTRU  102 . The Node-B(s)  104  may also transmit further channel allocation information in response to the E-DCH data transmission. Such further information may be included in the feedback information or may be sent as a separate transmission over the DL EU signaling channels  110   1-N . 
     The status of active EU procedures in the WTRU  102  may be used to provide input to the physical reception control entity  114  of the WTRU  102 . The physical reception control entity  114  communicates with a physical layer process to selectively enable and disable reception of the DL EU signaling channels  110   1-N . 
     In accordance with the present invention, the physical reception control entity  114  in the WTRU  102  disables reception, (i.e., ceases monitoring), of the DL EU signaling channels  1101 -N when it is not required by EU signaling procedures known to the WTRU  102 . During periods when the WTRU  102  is not required to receive the DL EU signaling channels  110   1-N , the processing requirements and power consumption of the WTRU  102  are reduced, and the possibility of false interpretation of DL signaling is avoided. 
       FIG. 2  is a flow diagram of a process  200  including method steps for selectively enabling reception of at least one DL EU signaling channel  110   1-N  during EU transmission in accordance with the present invention. In step  202 , the WTRU  102  is configured by the RNC  106  for E-DCH operation, whereby the UL EU channel  108  and the DL EU signaling channel(s)  110   1-N  are established between the WTRU  102  and the Node-B(s)  104 . The WTRU  102  is not required to enable the reception of its DL EU signaling channel(s)  110   1-N  immediately following configuration in the WTRU  102 . Thus, the physical reception control entity  114  in the WTRU  102  disables reception of DL EU signal channel(s)  110   1-N . 
     Still referring to  FIG. 2 , after the WTRU  102  is configured for E-DCH operation at step  202 , the WTRU  102  monitors its buffer  112  of E-DCH data (step  204 ). If, at step  206 , it is determined by the WTRU  102  that there is no E-DCH data in the buffer  112 , the WTRU  102  continues to monitor the buffer  112 , and reception of the DL EU signaling channels  110   1-N  remains disabled at step  204 . If, at step  206 , it is determined by the WTRU  102  that there is E-DCH data waiting (i.e., queued) for transmission via the UL EU channel  108 , the WTRU  102  transmits an EU channel allocation request with or without E-DCH data to the Node-B(s)  104  via the UL EU channel  108  and enables reception of at least one DL EU signaling channel  110   1-N  (step  208 ). The WTRU  102  may optionally enable reception of DL EU signaling channel(s)  110   1-N  after a predetermined or calculated delay. The EU channel allocation request may include scheduling information such as TVM information and available EU transmit power information. 
     Operation of E-DCH requires radio resource allocations to be scheduled and signaled by the Node-B(s)  104  to the WTRU  102  in response to an EU channel allocation request transmitted by the WTRU  102 . According to established signaling procedures, the WTRU  102  keeps track of when E-DCH data transmission scheduling information including EU channel allocations is required or expected to be received from the Node-B(s) on at least one DL EU signaling channel  110   1-N  based on information indicating when the EU channel allocation request was transmitted by the WTRU  102  (step  210 ). 
     In step  212 , the WTRU  102  receives the required or expected scheduling information from the Node-B(s) over the DL EU signaling channel(s)  110   1-N  and then, if not required by any one entity, the physical reception control entity  114  disables reception of DL EU signaling channel(s)  110   1-N . Optionally, in step  214 , the WTRU  102  schedules reception of DL EU signaling channel(s)  110   1-N  based on periodically received DL EU signaling channel scheduling information if configured. Reception of specific DL EU signaling channel(s)  110   1-N  is enabled, depending on which EU signaling procedures are active in the WTRU  102 . 
       FIG. 3  is a flow diagram of a process  300  including method steps for selectively enabling reception of the DL EU signaling channels  110   1-N  when the WTRU  102  sends E-DCH data and is expecting to receive feedback information in accordance with another embodiment of the present invention. In step  302 , the WTRU  102  is configured by the RNC  106  for E-DCH operation whereby the UL EU channel  108  and the DL EU signaling channel(s)  110   1-N  are established between the WTRU  102  and the Node-B(s)  104 . The WTRU  102  is not required to enable the reception of its DL EU signaling channel(s)  110   1-N  immediately following the E-DCH operation configuration of the WTRU  102 . Thus, the physical reception control entity  114  in the WTRU  102  disables reception of DL EU signal channel(s)  110   1-N . 
     Still referring to  FIG. 3 , after the WTRU  102  is configured to perform an E-DCH operation at step  302 , the WTRU  102  monitors its buffer  112  of E-DCH data (step  304 ). If at step  306  it is determined by the WTRU  102  that there is no E-DCH data in the buffer  112 , the WTRU  102  continues to monitor the buffer  112 , and reception of the DL EU signaling channel(s)  110   1-N  remains disabled at step  304 . 
     Steps  308 ,  310 ,  312  and  314  of process  300  may be performed for each of a plurality of several hybrid-automatic repeat request (H-ARQ) processes operating in parallel in the WTRU. If at step  306  it is determined by the WTRU  102  that there is E-DCH data waiting (i.e., queued) for transmission via the UL EU channel  108 , for each H-ARQ process, the WTRU  102  transmits E-DCH data with or without an EU channel allocation request to the Node-B(s)  104  via the UL EU channel  108  and enables reception of DL EU signaling channel(s)  110   1-N  (step  308 ). The WTRU  102  may optionally enable reception of DL EU signaling channel(s)  110   1-N  after a predetermined or calculated delay. 
     According to established signaling procedures, the WTRU  102  keeps track of when feedback information is required or expected to be received from the Node-B(s)  104  for each H-ARQ process (step  310 ). In step  312 , the WTRU receives feedback information from the Node-B(s)  104  and disables reception of the DL EU signaling channel(s)  110   1-N  if not required by any one entity. Optionally, in step  314 , the WTRU  102  schedules reception of the DL EU signaling channel(s)  110   1-N  based on periodically received feedback information if configured. Reception of specific DL EU signaling channel(s)  110   1-N  is enabled, depending on which EU signaling procedures are active in the WTRU  102 . 
     The WTRU  102  keeps track of when scheduling information including EU channel allocations is expected to be received on DL EU signaling channels  110   1-N  based on information indicating when the WTRU  102  transmitted the E-DCH data. DL EU signaling channels  110   1-N  are also used to provide the WTRU  102  feedback information from the Node-B(s)  104  for E-DCH transmissions. Since feedback transmitted to the WTRU is in response to a specific action of the WTRU, the time of feedback information reception at the WTRU can be accurately determined by the WTRU. Feedback information transmitted by the Node-B(s)  104  via the DL EU signaling channel(s)  110   1-N  may consist of H-ARQ acknowledgements and/or UL channel allocation information. One example of WTRU reception of feedback channels could be H-ARQ information channels (HICHs) and relative grant channels (RGCHs) or absolute grant channels (AGCH) in 3GPP. 
     The H-ARQ operation may be either synchronous or asynchronous. In synchronous operation, the WTRU  102  knows exactly when the WTRU  102  may receive the feedback (ACK or NACK) via DL EU signaling channel(s)  110   1-N  and the WTRU  102  enables reception of the DL EU signaling channel(s)  110   1-N  in accordance with a preconfigured schedule. With asynchronous H-ARQ operation, the WTRU enables reception of the DL EU signaling channel(s)  110   1-N  for a predetermined time period following the EU transmission for receiving the feedback. 
     Channel allocation feedback may also be transmitted to the WTRU  102  from the Node-B(s)  104  on DL EU signaling channel(s)  110   1-N . The WTRU  102  may also enable reception of DL EU signaling channel(s)  110   1-N  for this channel allocation feedback information. EU channel allocation procedures known to the WTRU  102  allow the WTRU  102  to schedule reception of this information. The channel allocation feedback may either be synchronized with the H-ARQ feedback, send over a predetermined period, or have a specified periodic repetition that the WTRU  102  can schedule reception for. 
     If the WTRU  102  does not send a channel allocation request to the Node-B(s)  104 , but all previous EU data transmission requests sent by the WTRU  102  have been serviced by the Node-B(s)  104 , and feedback information was received from the Node-B for all outstanding H-ARQ transmissions, then the WTRU  102  disables the reception of the DL EU signaling channel(s)  110   1-N . 
     In one embodiment, the WTRU  102  sends at least one channel allocation request to a plurality of Node-Bs  104  via at least one UL channel  108 , and the Node-Bs send channel allocation information to the WTRU  102  via respective downlink (DL) signaling channels  110   1-N  in response to receiving the channel allocation request. 
     The processor  120  in the WTRU  102  coordinates and consolidates DL signaling channel reception requirements of a plurality of channel allocation procedures carried out by the WTRU  102  in accordance with at least one established standard procedure stored in the standards database  122 , and determines whether or not to enable reception of specific ones of the DL signaling channels  110   1-N  based on the consolidated DL signaling channel reception requirements. The standards database  120  is in communication with the processor  120  and provides the processor  120  with information associated with at least one established standard procedure. The transmitter  118  is in communication with the processor  120  and sends at least one channel allocation request to the Node-Bs  104  via at least one UL channel  108 . The receiver  116  is in communication with the processor  120  and receives channel allocation information from the Node-Bs  104  over the DL signaling channels  110   1-N . The physical reception control entity  114  is in communication with the processor  120  and the receiver  116 . The physical reception control entity  114  enables or disables reception of specific ones of the DL signaling channels  110   1-N  based on the determination made by the processor  120 . 
     In another embodiment, the WTRU  102  sends at least one data transmission to a plurality of Node-Bs  104  via at least one UL channel  108 , and the Node-Bs  104  send data transmission feedback information to the WTRU  102  via respective downlink (DL) signaling channels  110   1-N  in response to receiving the data transmission. 
     The processor  120  in the WTRU  102  coordinates and consolidates DL signaling channel reception requirements of a plurality of data transmission procedures carried out by the WTRU in accordance with at least one established standard procedure stored in the standards database  122 , and determines whether or not to enable reception of specific ones of the DL signaling channels  110   1-N  based on the consolidated DL signaling channel reception requirements. The E-DCH data buffer  112  is in communication with the processor  120  and queues data to be included in at least one data transmission sent by the WTRU  102  to the Node-Bs  104  via at least one UL channel  108 . The transmitter  118  is in communication with the processor and sends the at least one data transmission to the Node-Bs  104 . The receiver  116  is in communication with the processor  120  and receives data transmission feedback information from the Node-Bs  104  over the DL signaling channels  110   1-N . The physical reception control entity  114  is in communication with the processor  120  and the receiver  116 . The physical reception control entity  114  enables or disables reception of specific ones of the DL signaling channels  110   1-N  based on the determination made by the processor  120 . 
     In yet another embodiment, the WTRU  102  sends at least one channel allocation request and E-DCH data to a plurality of Node-Bs  104  via at least one UL channel  108 , and the Node-Bs send channel allocation information and data feedback information associated with the E-DCH data to the WTRU  102  via respective downlink (DL) signaling channels  110   1-N  in response to receiving the at least one channel allocation request and E-DCH data. 
     The processor  120  in the WTRU  102  coordinates and consolidates DL signaling channel reception requirements of a plurality of channel allocation procedures and data transmission procedures carried out by the WTRU  102  in accordance with at least one established standard procedure stored in the standards database  122 , and determines whether or not to enable reception of specific ones of the DL signaling channels  110   1-N  based on the consolidated DL signaling channel reception requirements. The standards database  120  is in communication with the processor  120  and provides the processor  120  with information associated with at least one established standard procedure. The transmitter  118  is in communication with the processor  120  and sends at least one channel allocation request and E-DCH data to the Node-Bs  104  via at least one UL channel  108 . The receiver  116  is in communication with the processor  120  and receives channel allocation information from the Node-Bs  104  over the DL signaling channels  110   1-N . The physical reception control entity  114  is in communication with the processor  120  and the receiver  116 . The physical reception control entity  114  enables or disables reception of specific ones of the DL signaling channels  110   1-N  based on the determination made by the processor  120 . 
     Although the features and elements of the present invention are described in the preferred embodiments in particular combinations, each feature or element can be used alone without the other features and elements of the preferred embodiments or in various combinations with or without other features and elements of the present invention.