WO2016169326A1 - Procédé et appareil pour une procédure d'accès - Google Patents

Procédé et appareil pour une procédure d'accès Download PDF

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Publication number
WO2016169326A1
WO2016169326A1 PCT/CN2016/074026 CN2016074026W WO2016169326A1 WO 2016169326 A1 WO2016169326 A1 WO 2016169326A1 CN 2016074026 W CN2016074026 W CN 2016074026W WO 2016169326 A1 WO2016169326 A1 WO 2016169326A1
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WO
WIPO (PCT)
Prior art keywords
access response
base station
response
access
terminal device
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PCT/CN2016/074026
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English (en)
Inventor
Dandan HAO
Béla RATHONYI
Yanda TONG
Jingyue Nie
Jingling Wang
Shanyou SHAO
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Telefonaktiebolaget Lm Ericsson (Publ)
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Publication of WO2016169326A1 publication Critical patent/WO2016169326A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
    • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
    • H04L1/18—Automatic repetition systems, e.g. Van Duuren systems
    • H04L1/1829—Arrangements specially adapted for the receiver end
    • H04L1/1832—Details of sliding window management
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
    • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
    • H04L1/18—Automatic repetition systems, e.g. Van Duuren systems
    • H04L1/1829—Arrangements specially adapted for the receiver end
    • H04L1/1835—Buffer management
    • H04L1/1845—Combining techniques, e.g. code combining
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/08—Non-scheduled access, e.g. ALOHA
    • H04W74/0833—Random access procedures, e.g. with 4-step access

Definitions

  • Embodiments of the present invention generally relate to the field of communications, and more particularly to a method and apparatus for an access procedure.
  • one or more user equipments may communicate with one base station (BS) .
  • BS base station
  • the UE needs to access the BS first.
  • uplink communication refers to a communication from the UE to the BS.
  • downlink communication refers to a communication from the BS to the UE.
  • a random access procedure is typically used by the UE to access the BS.
  • Purposes for a random access include initial access, handover, downlink or uplink data arrival in connection status and UE positioning.
  • the UE wants to initiate a random access, the UE transmits a preamble to an eNodeB (eNB) on the Physical Random Access Channel (PRACH) , wherein this preamble sequence will be shared among multiple UEs.
  • the eNB Upon reception of the preamble, the eNB transmits to the UE a Random Access Response (RAR) on the Physical Downlink Shared Channel (PDSCH) .
  • the RAR is generated by the eNB for the preamble and carries an indication of uplink resources allocated by the eNB.
  • the UE may continue the access procedure using the allocated uplink resources. If the decoding is failed, the UE may initiate another random access procedure. In order to ensure a successful access, there is a need for improving reliability of message transmission between the UE and the BS during the access procedure.
  • Example UEs are machine type communication (MTC) devices which may include smart meters, wearable devices, vehicle-mounted devices, fire alarm devices, sensors and the like. Some of the MTC devices may be positioned in areas where the system coverage is not sufficient. For such an MTC device, the reliability of the communications during the access procedure particularly needs to be improved.
  • MTC machine type communication
  • a low cost MTC device provided with a single receiving (RX) antenna is proposed in 3GPP Release 12. Further, in 3GPP Release 13 Category ‘-1’ , it is proposed to reduce baseband and RF bandwidth of the MTC device to 1.4MHz. Due to the reduction of the RX antenna and the bandwidth, the performance of the MTC device may be degraded. As a result, for such a low cost MTC device, there is a particular need for improving the reliability of message transmission during the access procedure so as to ensure the successful access.
  • the eNB may transmit a RAR (Message 2) within a predetermined RAR window for only once.
  • the RAR window indicates a time period including a plurality of subframes.
  • the eNB may transmit the RAR to the UE, and accordingly the UE will decode the RAR if it has detected the RAR.
  • the UE may initiate another access attempt.
  • embodiments of the present invention provide an efficient solution for an access procedure.
  • a method in a base station of a communication network comprises: receiving an access request from a terminal device of the communication system; determining the number of transmission times for transmitting an access response for the received access request; and transmitting the access response to the terminal device the transmission times within a time period.
  • the corresponding computer program is also provided.
  • a method in a terminal device of a communication network comprises: transmitting an access request to a base station of the communication network; detecting an access response for the access request from the base station in a subframe included in a time period, the access response being transmitted by the base station one or more times; in response to detecting the access response in the subframe, decoding the access response; and in response to a success of the decoding and expiration of the time period, accessing the base station.
  • the corresponding computer program is also provided.
  • an apparatus in a base station of a communication network comprising: a receiving unit configured to receive an access request from a terminal device of the communication system; a transmission time determining unit configured to determine the number of transmission times for transmitting an access response for the received access request; and a transmitting unit configured to transmit the access response to the terminal device the transmission times within a time period.
  • an apparatus in a terminal device of a communication network comprising: a transmitting unit configured to transmit an access request to a base station of the communication network; an access response detecting unit configured to detect an access response for the access request from the base station in a subframe included in a time period, the access response being transmitted by the base station one or more times; an access response decoding unit configured to decode the access response in response to detecting the access response in the subframe; and an access unit configured to access the base station in response to a success of the decoding and expiration of the time period.
  • a base station of a communication network comprises a processor and a memory including computer-executable instructions which, when executed by the processor, cause the base station to: receive an access request from a terminal device of the communication system; determine the number of transmission times for transmitting an access response for the received access request; and transmit the access response to the terminal device the transmission times within a time period.
  • a terminal device of a communication network comprises a processor and a memory including computer-executable instructions which, when executed by the processor, cause the terminal device to: transmit an access request to a base station of the communication network; detect an access response for the access request from the base station in a subframe included in a time period, the access response being transmitted by the base station one or more times; in response to detecting the access response in the subframe, decode the access response; and in response to a success of the decoding and expiration of the time period, access the base station.
  • a base station of a communication network comprises processing means adapted to: receive an access request from a terminal device of the communication system; determine the number of transmission times for transmitting an access response for the received access request; and transmit the access response to the terminal device the transmission times within a time period.
  • a terminal device of a communication network comprises processing means adapted to: transmit an access request to a base station of the communication network; detect an access response for the access request from the base station in a subframe included in a time period, the access response being transmitted by the base station one or more times; in response to detecting the access response in the subframe, decode the access response; and in response to a success of the decoding and expiration of the time period, access the base station.
  • the access response for the access request may be transmitted for multiple times by the BS to the terminal device.
  • the probability that the terminal device decodes the access response successfully may be improved, and therefore the reliability of the message transmission during the access procedure may be effectively and efficiently improved.
  • the number of transmission times of the access response may be determined adaptively for the access request.
  • the access response may be transmitted multiple times if needed. Therefore, system flexibility is remained, while access efficiency is improved.
  • FIG. 1 illustrates an environment of a communication network in which embodiments of the present invention may be implemented
  • FIG. 2 illustrates a flowchart of a method for an access procedure in a base station in accordance with one embodiment of thc present invention
  • FIG. 3 illustrates an example correspondence between Timing Advance (TA) and the distance between the terminal device and the base station in accordance with one embodiment of the present invention
  • FIG. 4 illustrates a flowchart of a method for an access procedure in a terminal device in accordance with one embodiment of the present invention
  • FIG. 5 illustrates an example access procedure in the LTE system according to embodiments of the present invention
  • FIGS. 6a to 6f illustrate example subframe timing of an access procedure according to embodiments of the present invention
  • FIG. 7 illustrates a block diagram of an apparatus for an access procedure in a base station in accordance with one embodiment of the present invention
  • FIG. 8 illustrates a block diagram of an apparatus for an access procedure in a terminal device in accordance with one embodiment of the present invention.
  • FIG. 9 illustrates a simplified block diagram of an apparatus that is suitable for use in implementing embodiments of the present invention.
  • terminal device or “user equipment” (UE) refers to any terminal having wireless communication capabilities, including but not limited to, mobile phones, cellular phones, smart phones, or personal digital assistants (PDAs) , portable computers, image capture devices such as digital cameras, gaming devices, music storage and playback appliances, and any portable units or terminals that have wireless communication capabilities, or Internet appliances permitting wireless Internet access and browsing and the like.
  • PDAs personal digital assistants
  • BS base station
  • NodeB or NB node B
  • eNodeB or eNB evolved NodeB
  • RRU Remote Radio Unit
  • RH radio header
  • RRH remote radio head
  • Iow power node such as a femto, a pico, and so forth.
  • UE user equipment
  • eNodeB evolved NodeB
  • RRH remote radio head
  • Iow power node such as a femto, a pico, and so forth.
  • UE user equipment
  • terminal device may be used interchangeably and the terms “base station” or “BS” and “eNodeB” or “eNB” may be used interchangeably hereinafter.
  • FIG. 1 shows an environment of a communication system 100 in which embodiments of the present invention may be implemented.
  • two or more terminal devices 110 may communicate with a BS 120.
  • Example BSs include, but are not limited to, a macro BS, a low power BS such as a pico BS and a femto BS, and the like.
  • the communications between the terminal devices 110 and the BS 120 may be performed according to any suitable communication protocols including, but not limited to, the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the fifth generation (5G) communication protocols, and/or any other protocols either currently known or to be developed in the future.
  • suitable communication protocols including, but not limited to, the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the fifth generation (5G) communication protocols, and/or any other protocols either currently known or to be developed in the future.
  • the terminal device 110 may first initiate an access procedure. For example, the terminal device 110 may transmit an access request to the BS 120.
  • An example access request includes, but is not limited to, a preamble on the PRACH in the LTE system.
  • the BS 120 may transmit an access response, such as a RAR, to the terminal device 110.
  • the access response may carry uplink resources allocated by the BS 120 in response to the access request. If the terminal device 110 decodes the access response successfully, the terminal device 110 may continue access attempts to the BS 120 using the allocated uplink resources.
  • the BS 120 transmits the access response only once within a predetermined time period, such as the RAR window. With the only one transmission time, it is difficult for the terminal device to implement a successful decoding, especially for some special terminal devices, such as MTC UEs.
  • FIG. 2 shows a flowchart of a method 200 for an access procedure in a BS in accordance with one embodiment of the present invention. It would be appreciated that the method 200 may be implemented in the BS 120 as shown in FIG. 1.
  • the method 200 is entered at step 210, where the BS 120 receives an access request from the terminal device 110.
  • the access request may be any suitable request message used by the terminal device 110 to request accessing the BS 120.
  • An example access request includes, but is not limited to, a preamble on the PRACH, also referred to as a PRACH preamble, in the LTE system.
  • step 220 the BS 120 determines the number of transmission times for transmitting an access response in response to receiving the access request.
  • the BS may determine the number of transmission times for transmitting the corresponding access response. Accordingly, the same access response may be repeatedly transmitted for multiple times within a window by the BS 120 to the terminal device 110. In this way, the probability that the terminal device 110 decodes the access response successfully may be effectively and efficiently improved.
  • any suitable factors may be taken into account by the BS 120 when determining the number of transmission times.
  • the distance between the terminal device 110 and the BS 120 may be considered as a factor.
  • the method 200 may further comprise step 220, where the BS 120 determines the distance between the terminal device 110 and itself which may be used for determining the number of transmission times at step 240.
  • the BS 120 determines the distance between the terminal device 110 and itself which may be used for determining the number of transmission times at step 240.
  • fading of a communication channel between the terminal device and the BS is associated with the distance therebetween. Generally, the more the distance is, the more severe the fading is.
  • the determination of the number of transmission times with reference to the distance between the terminal device and the BS may efficiently improve the transmission reliability of the access response.
  • any suitable approach may be used to determine the distance between the terminal device 110 and the BS 120.
  • the BS 120 may obtain a location of the terminal device 110 first. Then, the BS 120 may determine the distance between the terminal device 110 and itself based on the location of the terminal device 110.
  • Any suitable positioning methods may be used for positioning the terminal device 110.
  • Example positioning methods include, but are not limited to, a Global Positioning System (GPS) assisted positioning method, a triangulation localization method and the like.
  • GPS Global Positioning System
  • any suitable rules may be used to determine the number of transmission times with reference to the determined distance.
  • the number of transmission times may be determined in proportional to the distance. It should be understood that a path loss will be increased with the increasing of the distance.
  • the probability that the terminal device decodes the access response successfully may be improved in a scenario with a larger path loss.
  • the determination of the number of transmission times in proportional to the distance between the terminal device and the BS may be implemented based on comparison with thresholds. Specifically, the distance may be compared with a plurality of predetermined distance thresholds. In response to the distance falling within different threshold ranges, the number of transmission times may be set as different values. For example, if the distance falls within a lower threshold range between smaller distance thresholds, the number of transmission times may be set as a smaller value. If the distance falls within a higher threshold range between larger distance thresholds, the number of transmission times may be set as a larger value.
  • the proportionality between the number of the transmission times and the distance is only for the purpose of illustration without any limitation. In some applications, with the increasing of the distance between the terminal device and the BS, the number of transmission times may be the same or decreased, for example, considering other factors and/or according to actual needs.
  • a coverage range of the BS 120 may also be taken into account.
  • the distance thresholds used by the BS having a larger coverage range, such as the macro BS, to compare with the distance between the terminal device and the BS may have larger granularity than those used by the BS having a smaller coverage range, such as the low power BS.
  • the coverage range of the macro BS is generally larger than that of the low power BS. Accordingly, a distance that indicates the proximity of the terminal device 110 to the macro BS may indicate the remoteness of the terminal device 110 from the low power BS.
  • the distance threshold having larger granularity corresponding to the larger BS coverage range the number of transmission times may be more effectively and efficiently determined with reference to the distance between the terminal device and the BS. It should be appreciated that this is only for the purpose of illustration without suggesting the limitations on the consideration of the coverage range of the BS in determining the number of transmission times.
  • the distance thresholds used by the macro BS may have the same granularity as those used by the low power BS.
  • the BS 120 may determine a delay metric associated with the distance between the terminal device 110 and itself.
  • An example delay metric may be Timing Advance (TA) in the LTE system.
  • TA Timing Advance
  • the TA represents time difference between the reception of uplink transmission and subframe timing at the network side, which may be used to control uplink transmission timing.
  • the TA may indicate the distance between the terminal device 110 and the BS 120.
  • FIG. 3 illustrates an example correspondence between the TA and the distance. As shown, the larger TA indicates the larger distance. In this case, the number of transmission times may be determined with reference to the TA representing the distance between the terminal device 110 and the BS 120.
  • Table 1 mapping between the TA and the number of transmission times
  • the granularity of Thresholdi used by the macro BS may be larger than that of Threshold i used by the low power BS.
  • uplink channel quality associated with the terminal device may be taken into account.
  • the method 200 may comprise step 230, where the BS 120 determines the uplink channel quality based on the access request received from the terminal device. Then, the determined uplink channel quality may be used for determining the number of transmission times for transmitting the access response at step 240.
  • the channel quality refers to fading characteristic of a communication channel, which may be identified by any suitable quality factors such as signal-to-noise ratio (SNR) , signal-to-interference plus noise ratio (SINR) , signal-to-noise plus distortion ratio (SNDR) and the like.
  • SNR signal-to-noise ratio
  • SINR signal-to-interference plus noise ratio
  • SNDR signal-to-noise plus distortion ratio
  • the uplink channel quality that is determined based on the access request from the terminal device 110 may indicate radio conditions of the communication system 100 comprising the terminal device 110 and the BS 120. With the determination of the number of transmission times of the access response within a time period with reference to the uplink channel quality, the transmission reliability of the access response may be improved.
  • the UE may transmit a preamble on the PRACH as the access request for accessing the eNB.
  • the eNB may be aware of the channel quality of the PRACH on which the received preamble transmitted from the UE. Then, the eNB may determine the number of transmission times for transmitting the RAR on the PDSCH.
  • TDD Time Division Duplexing
  • the PRACH and the PDSCH are provided within a same frequency band, and therefore the channel quality of the PRACH may be closely associated with that of the PDSCH.
  • the transmission reliability of the access response may be particularly increased by using the channel quality of the PRACH to determine the number of transmission times for transmitting the RAR on the PDSCH.
  • the number of transmission times may be determined considering a property of the cell that is served by the BS 120.
  • the property of the cell may be any suitable cell characteristics that may contribute to the reliability of the communications between the terminal device and the BS.
  • the cell property may be a cell type.
  • a macro cell served by the macro BS is larger than a low power cell served by the low power cell.
  • the threshold granularity for the macro cell may be larger than that for the low power cell. In this way, the number of transmission times for transmitting the access response may be determined more effectively and efficiently.
  • the cell property may be cell environment.
  • the cell environments may be different per cell.
  • some cells may be located in an urban scenario, some others may be in a rural scenario. It should be understood that the cell in the urban scenario may suffer worse radio conditions for instance because of skyscrapers, tunnels or self-location than the cell in the rural scenario.
  • the number of transmission times for the urban cell may be set to be larger than that for the rural cell.
  • the factors for determining the number of transmission times may be considered by the BS 120 separately or in any suitable combinations.
  • the BS may use one of the distance between the terminal device and the BS, the uplink channel quality and the cell property, or the combination thereof to determine the number of transmission times.
  • the method 200 proceeds to step 250 where the BS 120 transmits the access response to the terminal device 110 the transmission times within a time period.
  • the time period may include a plurality of subframes.
  • An example of the time period may be the RAR window in the LTE system.
  • a length of the time period may be set statically, semi-statically or dynamically at a network side. Specifically, the length of the time period may be set statically per cell. For example, if the number of transmission times required by a cell is larger, the time period for the cell may be statically set to be longer. Alternatively or additionally, the length of the time period may be adjusted semi-statically or dynamically according to actual needs. For example, in the case when the time period is set to be long for a cell, if it is found that the cell does not require such a long time period, the time period may be adjusted to be shorter so as to reduce an unnecessary waste of resources.
  • the indication of the time period may be broadcast to the terminal device 110 in any suitable system messages such that the terminal device 110 may detect and decode the access response within the time period.
  • An example system message for carrying the indication of the time period includes, but is not limited to, a system information block (SIB) .
  • SIB system information block
  • any repetition patterns may be used for the transmission.
  • the access response may be transmitted repeatedly in multiple subsequent subframes.
  • the subframes for transmitting the access response may be separated by any suitable intervals so as to provide equal scheduling for multiple terminal devices 110 in the system 100.
  • Example subframe timing of transmitting the access response from the BS 120 to the terminal device 110 within the time period may be described below with reference to FIGS. 6a to 6f.
  • FIG. 4 shows a flowchart of a method 400 for an access procedure in a terminal device in accordance with one embodiment of the present invention. It would be appreciated that the method 400 may be implemented in the terminal device 110 as shown in FIG. 1.
  • the method 400 is entered at step 410, where the terminal device 110 sends an access request to the BS 120.
  • the access request may be any suitable request message that may be used by the terminal device 110 to requesting accessing the BS 120.
  • An example access request may be a PRACH preamble in the LTE system.
  • the method 400 proceeds to step 420, where the terminal device 110 detects an access response to the access request from the BS 120 in a subframe within a time period, such as the RAR window.
  • the access response may be transmitted by the BS 120 one or more times so as to improve the probability that the terminal device 110 decodes the access response successfully.
  • any suitable factors may be taken into account by the BS 120 to determine the number of transmission times for transmitting the access response.
  • the RAR window typically include a plurality of subframes.
  • the length of the RAR window may be set statically, semi-statically or dynamically at the network side and notified, for example, broadcasted to the terminal device 110 in a system message, such as a system information block (SIB) .
  • SIB system information block
  • the access response may be transmitted repeatedly in multiple subsequent subframes or in multiple subframes that are separated by any suitable intervals.
  • any suitable detection approaches may be used by the terminal device 110 to detect the access response from the BS 120.
  • a Physical Downlink Control Channel (PDCCH) or ePDCCH is used by the eNB to carry an indication of time and/or frequency resources for transmitting the access response.
  • the UE may monitor PDCCH or ePDCCH in every subframe. If the UE detects the PDCCH or ePDCCH, the UE may determine that the BS possibly has transmitted the RAR for its PRACH preamble. This is only for the purpose of illustration without suggesting any limitations on the detection approaches of the access response. The scope of the present invention will not be limited in this regard.
  • step 420 the method 400 proceeds to step 430, where the terminal device 110 decodes the access response.
  • Any suitable decoding algorithms may be used which may include a Viterbi decoding algorithm, a Maximum A Priori Probability (MAP) decoding algorithm and the like.
  • the method 400 proceeds to step 440, where the terminal device 110 determines whether the decoding is successful or not. If the decoding is successful, the terminal device 110 accesses the BS 120 in response to expiration of the time period, such as the RAR window, at step 480. For example, Message 3 may be transmitted to the BS from the terminal device. As described above, the access response may be transmitted by the BS 120 many times. On the other side, the terminal device has no idea for how many times the RAR is transmitted within the RAR window until the entire RAR window has expired. Therefore, it is benefit that the terminal device sends Message 3 after the expiration of the RAR window. Cooperatively, the BS prepares for the reception of Message 3 after the certain time period. Practically, after the RAR window expires, the terminal device and the BS at both sides may wait for a little more time such as the duration of the decoding process before the transmission of Message 3.
  • the process of accessing the BS by the terminal device may include any suitable processes where the terminal device may use the uplink resources that have been scheduled by the BS via the access response, such as the RAR.
  • the RAR transmitted by the eNB as the access response may carry allocated uplink resources.
  • the UE may use the uplink resources to transmit Message 3 (Msg3) to transfer connection setup request message from a high layer, such as RRC layer.
  • Msg3 Message 3
  • the terminal device may initiate uplink data transmission using the uplink resources allocated by the BS.
  • the method 400 may proceed to step 460, where the terminal device 110 may detect the access response in a subsequent subframe within the RAR window.
  • the access response may be transmitted many times by the BS. The continuous detecting of the access response in a plurality of subframes enables a simple and practical detection implementation where the terminal device is unnecessarily aware of the number of transmission times and the subframe timing of the access response.
  • the decoding of the access response may take use of previous decoding information.
  • the decoding information may be any suitable information that may be used for the combined decoding of the access response to improve the probability of the successful decoding.
  • Example decoding information includes, but is not limited to, decoded softbits, demodulated bits, received in-phase/quadrature (I/Q) data and the like.
  • a softbit refers to a probability that the value of the associated bit is one or zero.
  • the method 400 may further comprise step 450, where the terminal device 110 may store the decoding information obtained in the present decoding attempt. Furthermore, if the access response is detected in a subsequent subframe at step 460, the terminal device 110 may perform the combined decoding on the access response using the stored decoding information at step 470.
  • the storing of the decoding information in response to a failed decoding is only for the purpose of illustration without suggesting any limitations.
  • the decoding information obtained in a decoding attempt may be stored at any suitable time.
  • the received I/Q data for the combined decoding the received I/Q data of the access response may be buffered by the terminal device as the decoding information upon the reception of the access response by a receiver of the terminal device.
  • the demodulated bits of the access response may be saved after the received access response is demodulated by a demodulator of the terminal device.
  • the decoded softbits obtained in decoding may be buffered as the decoding information. If the access response is detected in another subframe, the stored softbits may be used in combine with the subsequently detected access response to perform the combined decoding.
  • FIG. 5 shows an example access procedure 500 in the LTE system according to embodiments of the present invention.
  • the procedure 500 begins with step 501, where the UE selects a preamble and sends the preamble to the eNB on the PRACH.
  • the eNB detects the preamble and determines the number of transmission times for transmitting a RAR for the UE.
  • the UE monitors an ePDCCH in the first subframe of the RAR window.
  • the UE determines whether there is the ePDCCH. If the ePDCCH exists, which means the RAR has been transmitted within the present subframe, the UE decodes the RAR at step 505.
  • the decoding of the RAR may use previous decoded softbits that are obtained in previous decoding attempts and has been stored in a buffer of the UE.
  • the procedure 500 proceeds to step 506, where the UE determines whether the decoding is successful or not. If the decoding is successful, the UE clears the softbits in the buffer storage at step 507, and then prepares for transmitting Msg3 in the subframe with a serial number of (n+ (m-1) +6+UL_Delay) at step 508.
  • n represents a sequence number of the first subframe included in the RAR window
  • m represents the length of the RAR window
  • 6 is the time period for decoding
  • UL_Delay is a system parameter that may be configured to be 0 or 1.
  • the procedure 500 proceeds to step 509, where the UE buffers the softbits of the RAR obtained in this decoding attempt. Then, the procedure 500 proceeds to step 510, where the UE determines whether the current subframe is the last subframe in the RAR window. If the current subframe is not the last subframe, the UE monitors the ePDCCH in the next subframe of the RAR window at step 511. Then, the procedure 500 returns to step 504 and thereby repeats the decoding of the RAR and subsequent processes for the next subframe.
  • the procedure 500 also proceeds to step 510 of determining whether the current subframe is the last subframe. In this way, the UE may detect and decode the RAR from the eNB one by one subframe.
  • the procedure 500 proceeds to step 512, where the UE determines whether the maximum number of the PRACH preamble transmission is reached or not. If the maximum number is not reached, the UE selects backoff time according to system parameters and initiates the next PRACH preamble transmission based on the backoff time at step 513. Then, the procedure 500 returns to step 501. If the maximum number of the PRACH preamble transmission is reached, the access procedure 500 is failed and ends at step 514.
  • FIGS. 6a to 6f show example subframe timing of an access procedure according to embodiments of the present invention. It should be appreciated that the example subframe timing may be used in the access procedure 500 as shown in FIG. 5.
  • the RAR window includes m subframes and starts from the subframe 610 with a serial number of n.
  • FIG. 6a shows an example where there is no repetition of RAR transmission and the eNB transmits the RAR only once in the subframe 610 within the RAR window.
  • FIG. 6b shows another example where the eNB uses the subframes 610, 620, 630 and 640 in the RAR window to transmit the RAR four times.
  • FIG. 6c shows yet another example where the eNB uses the subframes 610, 630 and 650 to transmit the RAR, which shows that the repeated RAR transmission occupying multiple subframes are not subsequent but separated by certain intervals.
  • UL_Delay is assigned to be “0” . Accordingly, upon the successful decoding of the RAR, the UE transmits Msg3 in the subframe 660 with a serial number of (n+m+5) .
  • the RAR has the same subframe timing in FIGS. 6d to 6f as in FIGS. 6a to 6c.
  • the difference is that UL_Delay is assigned to be “1” in FIGS. 6d to 6f instead of “0” in FIGS. 6a to 6c.
  • the UE transmits Msg3 in the subframe 670 with a serial number of (n+m+6) in response to the successful decoding of the RAR.
  • FIG. 7 shows a block diagram of an apparatus 700 for an access procedure in a BS in accordance with one embodiment of the present invention. It would be appreciated that the apparatus 700 may be implemented by the BS 120 as shown in FIG. 1.
  • the apparatus 700 comprises a receiving unit 710, a transmission time determining unit 720 and a transmitting unit 730.
  • the receiving unit 710 is configured to receive an access request from a terminal device of the communication system.
  • the transmission time determining unit 720 is configured to determine the number of transmission times for transmitting an access response for the received access request.
  • the transmitting unit 730 is configured to transmit the access response to the terminal device the transmission times within a time period.
  • the apparatus 700 may further comprise a distance determining unit 740 configured to determine the distance between the terminal device and the base station.
  • the transmission time determining unit 720 may be further configured to determine the number of transmission times with reference to the determined distance.
  • the transmission time determining unit 720 may be further configured to determine the number of transmission times with reference to the determined distance and a coverage range of the base station.
  • the determining the distance determining unit 740 may comprise a delay determining unit configured to determine a delay metric associated with the distance between the terminal device and the base station.
  • the delay metric is determined from a timing advance.
  • the apparatus 700 may further comprise a channel quality determining unit 750 configured to determine uplink channel quality based on the received access request.
  • the transmission time determining unit 720 may be further configured to determine the number of transmission times with reference to the determined uplink channel quality.
  • the transmission time determining unit 720 may be further configured to determine the number of transmission times with reference to a property of a cell that is served by the base station.
  • FIG. 8 shows a block diagram of an apparatus 800 in a terminal device for requesting scheduling in accordance with one embodiment of the present invention. It would be appreciated that the apparatus 800 may be implemented by the terminal device 110 as shown in FIG. 1.
  • the apparatus 800 comprises a transmitting unit 810, an access response detecting unit 820, an access response decoding unit 830 and an accessing unit 840.
  • the transmitting unit 810 is configured to transmit an access request to a base station of the communication network.
  • the access response detecting unit 820 is configured to detect an access response for the access request from the base station in a subframe included in a time period, wherein the access response is transmitted by the base station one or more times.
  • the access response decoding unit 830 is configured to decode the access response in response to detecting the access response in the subframe.
  • the accessing unit 840 is configured to access the base station in response to a success of the decoding and expiration of the time period.
  • the access response detecting unit 820 may be further configured to detect the access response in a subsequent subframe included in the time period in response to a failure of the decoding.
  • the apparatus 800 may comprise a decoding information storing unit 850 configured to store decoding information associated with the access response in response to the failure of the decoding.
  • the access response decoding unit 820 may be further configured to decode the access response in combination with the stored decoding information in response to detecting the access response in the subsequent subframe.
  • the units included in the apparatuses 700 and 800 may be implemented in various manners, including software, hardware, firmware, or any combination thereof.
  • one or more units may be implemented using software and/or firmware, for example, machine-executable instructions stored on the storage medium.
  • parts or all of the units in the apparatus 300 may be implemented, at least in part, by one or more hardware logic components.
  • FPGAs Field-programmable Gate Arrays
  • ASICs Application-specific Integrated Circuits
  • ASSPs Application-specific Standard Products
  • SOCs System-on-a-chip systems
  • CPLDs Complex Programmable Logic Devices
  • FIG. 9 shows a simplified block diagram of an apparatus 900 that is suitable for use in implementing embodiments of the present invention.
  • the apparatus 900 may be implemented in the terminal device 110 or the BS 120 as shown in FIG. 1.
  • the apparatus 900 includes a data processor (DP) 910, a memory (MEM) 920 coupled to the DP 910, a suitable RF transmitter TX and receiver RX 940 coupled to the DP 910, and a communication interface 950 coupled to the DP 910.
  • the MEM 920 stores a program (PROG) 930.
  • the TX/RX 940 is for bidirectional wireless communications. Note that the TX/RX 940 has at least one antenna to facilitate communication, though in practice an Access Node mentioned in this application may have several ones.
  • the communication interface 950 may represent any interface that is necessary for communication with other entities, such as an interface for communications between the UE and the eNB, X2 interface for bidirectional communications between eNBs, S1 interface for communication between a Mobility Management Entity (MME) /Serving Gateway (S-GW) and the eNB, or Un interface for communication between the eNB and a relay node (RN) .
  • the apparatus 900 may be coupled via a data path to one or more external networks or systems, such as the internet, for example.
  • the PROG 930 is assumed to include program instructions that, when executed by the associated DP 910, enable the apparatus 900 to operate in accordance with the embodiments of the present invention, as discussed herein with the method 200 in FIG. 2 and the method 400 in FIG. 4.
  • the embodiments herein may be implemented by computer software executable by the DP 910 of the apparatus 900, or by hardware, or by a combination of software and hardware.
  • a combination of the DP 910 and MEM 920 may form processing means 960 adapted to implement various embodiments of the present invention.
  • the MEM 920 may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory, as non-limiting examples. While only one MEM is shown in the apparatus 900, there may be several physically distinct memory modules in the apparatus 900.
  • the DP 910 may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples.
  • the apparatus 900 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.
  • various embodiments of the present invention may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present invention are illustrated and described as block diagrams, flowcharts, or using some other pictorial representation, it will be appreciated that the blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.
  • embodiments of the present invention can be described in the general context of machine-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor.
  • program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types.
  • the functionality of the program modules may be combined or split between program modules as desired in various embodiments.
  • Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.
  • Program code for carrying out methods of the present invention may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented.
  • the program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.
  • a machine readable medium may be any tangible medium that may contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.
  • the machine readable medium may be a machine readable signal medium or a machine readable storage medium.
  • a machine readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing.
  • machine readable storage medium More specific examples of the machine readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM) , a read-only memory (ROM) , an erasable programmable read-only memory (EPROM or Flash memory) , an optical fiber, a portable compact disc read-only memory (CD-ROM) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.
  • RAM random access memory
  • ROM read-only memory
  • EPROM or Flash memory erasable programmable read-only memory
  • CD-ROM portable compact disc read-only memory
  • magnetic storage device or any suitable combination of the foregoing.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

Conformément à des modes de réalisation, l'invention concerne d'une manière générale une procédure d'accès dans un réseau de communication. La station de base peut recevoir une requête d'accès à partir d'un dispositif de terminal du système de communication, déterminer le nombre de transmissions pour transmettre une réponse d'accès pour la requête d'accès reçue et transmettre la réponse d'accès au dispositif de terminal le nombre de transmissions dans une période de temps. De cette manière, la fiabilité de la transmission de message durant la procédure d'accès peut être améliorée de manière efficace et effective.
PCT/CN2016/074026 2015-04-24 2016-02-18 Procédé et appareil pour une procédure d'accès WO2016169326A1 (fr)

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CNPCT/CN2015/077400 2015-04-24
CN2015077400 2015-04-24

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010127633A1 (fr) * 2009-05-07 2010-11-11 大唐移动通信设备有限公司 Procédé, système et dispositif de détermination des informations de position d'un terminal utilisateur
WO2012091649A1 (fr) * 2010-12-30 2012-07-05 Telefonaktiebolaget L M Ericsson (Publ) Synchronisation de la transmission dans le sens montant
US20140050213A1 (en) * 2012-08-17 2014-02-20 Qualcomm Incorporated Methods and apparatus for timing synchronization during a wireless uplink random access procedure
WO2015012137A2 (fr) * 2013-07-23 2015-01-29 Nec Corporation Système de communication

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010127633A1 (fr) * 2009-05-07 2010-11-11 大唐移动通信设备有限公司 Procédé, système et dispositif de détermination des informations de position d'un terminal utilisateur
WO2012091649A1 (fr) * 2010-12-30 2012-07-05 Telefonaktiebolaget L M Ericsson (Publ) Synchronisation de la transmission dans le sens montant
US20140050213A1 (en) * 2012-08-17 2014-02-20 Qualcomm Incorporated Methods and apparatus for timing synchronization during a wireless uplink random access procedure
WO2015012137A2 (fr) * 2013-07-23 2015-01-29 Nec Corporation Système de communication

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