Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W72/00—Local resource management
  • H04W72/12—Wireless traffic scheduling
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04J—MULTIPLEX COMMUNICATION
  • H04J13/00—Code division multiplex systems
  • H04J13/10—Code generation
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L5/00—Arrangements affording multiple use of the transmission path
  • H04L5/0001—Arrangements for dividing the transmission path
  • H04L5/0014—Three-dimensional division
  • H04L5/0016—Time-frequency-code
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W72/00—Local resource management
  • H04W72/30—Resource management for broadcast services
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W76/00—Connection management
  • H04W76/10—Connection setup
  • H04W76/14—Direct-mode setup
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W8/00—Network data management
  • H04W8/005—Discovery of network devices, e.g. terminals

Definitions

• the present disclosure relates to mobile communication technology, and particularly to a method of implementing Device-to-Device broadcast communication in a wireless communication network and a corresponding user equipment.
• D2D communication has been introduced as an important enhancement to LTE-Advanced (Long Term Evolution) for cellular networks.
• the related standardization has been carried out in 3 GPP (Third-Generation Partnership Project) to study both device discovery and direct communication techniques.
• broadcast communication in out-of-coverage scenario is prioritized for Release 12 time frame. It is the most critical task for D2D broadcast communication to support VoIP traffic. It's required for a broadcast packet to reach a user equipment (UE) as far as possible. To increase coverage, a narrow band (as low as 2 or 3 RBs) is a suitable choice for transmission of a broadcast VoIP packet. For a large channel bandwidth (50 RBs for 10MHz bandwidth), we need to FDM (frequency domain multiplexing) broadcast transmissions from multiple UEs to fully use available spectral resources. However, it incurs half-duplex constraint and in-band emissions which eventually impact broadcast performance.
• FDM frequency domain multiplexing
• this invention provides a solution for D2D broadcast communication.
• a method in a user equipment in a wireless communication network, of implementing Device-to-Device broadcast communication, the method comprises following steps:- determining a transmission pattern set, which includes all rows except the first row in a Walsh matrix Hi and a first matrix H 2 , wherein the first matrix H 2 is a product of the Walsh matrix Hi and -1 ;- determining one row from the transmission pattern set; and- implement a Device-to-Device broadcast according to a transmission pattern corresponding to the determined row, wherein the transmission pattern is: implementing the following procedures based on each element in the determined row successively:- transmitting the broadcast when the element is a first value;- receiving the broadcast when the element is a second value.
• the transmission pattern set includes the even rows in the Walsh matrix Hi and the first matrix H 2 .
• a mechanism to down-select suitable transmission patterns is designed for a narrow band, such as 3MHz and 5MHz, so as to provide additional benefits.
• a narrow band such as 3MHz and 5MHz
• transmissions of a VoIP packet are spread more uniformly which helps to accomplish time diversity. Further, this mechanism helps to reduce overall transmission latency of a VoIP packet.
• a user equipment in a wireless communication network, of implementing Device-to-Device broadcast communication, the user equipment comprises:- unit for determining a transmission pattern set, configured for determining a transmission pattern set, which includes all rows except the first row in a Walsh matrix Hi and a first matrix H 2 , wherein the first matrix H 2 is a product of the Walsh matrix Hi and -1 ;- unit for determining one row, configured for determining one row from the transmission pattern set; and- broadcasting unit, configured for implementing a Device-to-Device broadcast according to a transmission pattern corresponding to the determined row, wherein the transmission pattern is: implementing the following procedures based on each element in the determined row successively:- transmitting the broadcast when the element is a first value;- receiving the broadcast when the element is a second value.
• the transmission pattern set is proposed.
• the total number of transmission patterns is (N-l)*2.
• N is the order of a Walsh matrix. This will help to reduce the collision probability in resource allocation and increase transmission pattern selection.
• the transmission pattern according to the present invention still keep the feature of Walsh based transmission pattern set.
• Fig. l illustrates constructing a Walsh matrix-based transmission pattern set according to an embodiment of the present invention
• Fig.2 illustrates a Walsh matrix-based transmission pattern set according to an embodiment of the present invention
• Fig.3 illustrates a flow chart of a method of implementing D2D broadcast communication according to an embodiment of the present invention
• Fig. 4 illustrates a relationship between two corresponding rows in two matrixes in a transmission pattern set according to an embodiment of the present invention
• Fig. 5 illustrates a relationship between two arbitrary rows in two matrixes in a transmission pattern set according to an embodiment of the present invention
• Fig. 6 illustrates a Walsh matrix-based transmission pattern set according to an embodiment of the present invention
• Fig. 7 illustrates a Walsh matrix-based transmission pattern set according to another embodiment of the present invention.
• Fig. 8 illustrates a Walsh matrix-based transmission pattern set according to a further embodiment of the present invention
• Fig. 9 illustrates a Walsh matrix-based transmission pattern set according to a further embodiment of the present invention.
• Fig. 10 illustrates a UE according to an embodiment of the present invention.
• LTE frame structure is reused to keep compatibility with legacy cellular communication.
• the minimum scheduling (resource allocation) unit consists of two time-consecutive resource blocks within one subframe, which is referred to as a resource-block (RB) pair.
• the resource allocation unit for D2D broadcast communication should be multiple of
• RB pairs For D2D communication, it's required for a broadcast packet to reach a UE as far as possible. To increase coverage, the narrow band (as low as 2 or 3 RBs) is a suitable choice for transmission of a broadcast VoIP packet. For a large channel bandwidth (50 RBs for 10MHz bandwidth), we need to FDM (frequency domain multiplexing) broadcast transmissions from multiple UEs to fully use available spectral resources.
• FDM frequency domain multiplexing
• VoIP traffic which is the basic traffic type for the D2D broadcast communication.
• VoIP traffic has the following properties:
• VoIP traffic is periodical.
• the encoder frame length is 20 ms which means a voice encoder generates a voice packet for each 20ms.
• the mean length of a talk spurt is 2.5s.
• the voice payload per speech frame is 328 bits with header compression.
• the requirement of end-to-end latency for VoIP traffic is 200ms.
• the tolerable transmission delay of a VoIP packet for D2D broadcast communication (unidirectional transmission) is about 160ms.
• Fig. l illustrates constructing a Walsh matrix-based transmission pattern set according to an embodiment of the present invention.
• the order N of the Walsh matrix is set as 8 only for illustration.
• one Walsh matrix Hi is selected firstly. It has an order of N.
• a first matrix H 2 is obtained as the product of the Walsh matrix Hi and - 1.
• Each row in this transmission pattern set can be used by a UE.
• Each element in each row can be used to determine whether the UE performs broadcast transmitting or broadcast receiving in one subframe. For example, for element +1 , the UE can perform broadcast
• the UE can perform broadcast receiving.
• Fig.3 illustrates a flow chart of a method of implementing D2D broadcast communication at the UE according to an embodiment of the present invention.
• step S l l the UE determines a transmission pattern set, which includes all rows except the first row in a Walsh matrix Hi and a first matrix H 2 , wherein the first matrix H 2 is a product of the Walsh matrix Hi and -1.
• the UE and the base station can predefine a corresponding transmission pattern set, and preconfigure it in the UE.
• the UE needs to perform a broadcast communication, it will use the transmission pattern set.
• the base station can determine the transmission pattern set, and transmit the determined transmission pattern set to the UE by a first indication message.
• The, the UE can determine the transmission pattern set according to the first indication message.
• This first indication message can be transmitted during the scheduling procedure, for example.
• step S I 2 the UE determines one row from the transmission pattern set.
• the UE receives a second indication message from the base station.
• This second indication message indicates an associated row.
• the UE determines the row from the transmission pattern set according to the second indication message.
• the base station determines the corresponding row for the respective UE according to the usage in the transmission pattern set, for example, so as to perform the corresponding broadcast.
• the UE itself can determine the row form the transmission pattern set according to the predefined conditions. Those predefined conditions includes current usage situation of each row in the transmission pattern set; current interested broadcast from other user equipment; and/or the quality of a current channel. For example, when the UE is very interested in the broadcast of another UE, it can select the corresponding suitable row to receive the broadcast in the respective subframe. However, when the UE is not interested in the broadcast of another UE, it can select the corresponding suitable row to transmit the broadcast in the respective subframe.
• step S 13 the UE performs D2D broadcast according to the transmission pattern corresponding to the determined row.
• the transmission pattern is: implementing the following procedures based on each element in the determined row successively: - transmitting the broadcast when the element is a first value (+1 , for example);- receiving the broadcast when the element is a second value (-1, for example).
• Fig. 4 illustrates a relationship between two corresponding rows in two matrixes in a transmission pattern set according to an embodiment of the present invention.
• Fig. 5 illustrates a relationship between two arbitrary rows in two matrixes in a transmission pattern set according to an embodiment of the present invention.
• H(i,:) represents the row i in the matrix H.
• Fig.5 shows four situations: the third and sixth rows in the Walsh matrix H 1 ? the third and sixth rows in the first Walsh matrix H 2 , the third row in the Walsh matrix Hi and the sixth row in the first Walsh matrix H 2 , and the sixth row in the Walsh matrix Hi and the third row in the first Walsh matrix H 2 .
• the number of potential transmission subframes for a VoIP packet is preconfigured as N.
• a broadcast UE determines whether to transmit/receive at potential transmission subframes.
• Fig. 6 illustrates a Walsh matrix-based transmission pattern set according to an embodiment of the present invention. It is assumed that the UE 1 performs the broadcast transmission based on the 3rd row in the Walsh matrix H 1 ? and the UE2 performs the broadcast transmission based on the 6th row in the first Walsh matrix H 2 . Based on the feature of the abovementioned two matrixes, the broadcast has the following properties: 1. Each broadcast UE transmits a VoIP packet N/2 times.
• the UE 1 can receive the broadcast transmissions from the UE 2 at least N/4 times, and vice versa, which resolves half-duplex constraint.
• the UE1 can receive broadcast transmissions from the UE2 N/2 times, and vice versa.
• the UE1 can receive broadcast transmissions from the UE2 N/4 times, and vice versa.
• Fig. 7 illustrates a Walsh matrix-based transmission pattern set according to another embodiment of the present invention. If the transmission patterns are based on two corresponding rows in Hi and H 2 , all potential transmission subframes can be occupied for
• the UE 1 uses the 3rd row in the matrix H 1 ? and the UE 2 uses the 3rd row in the matrix H 2 .
• the UE 3 uses the 6th row in the matrix H 1 ? and the UE 4 uses the 6th row in the matrix H 2
• Transmission pattern set By using the transmission pattern set, multiple transmissions of a VoIP packet are randomized in time domain which alleviates in-band emission seen at receiving UEs.
• Transmission pattern is fixed once the row of Walsh matrix for transmission pattern is chosen. Fixed
• transmission pattern facilitates the packet reception/combining at receiving UEs. And it also reduces signaling overhead if transmission pattern information is conveyed in scheduling assignment before data transmission. For narrower channel bandwidths such as 3MHz (15 resource blocks) and 5MHz (25 resource blocks), it is not necessary to use all the rows of the transmission pattern set. Hence for this case, the
• Transmissions of a VoIP packet are spread more uniformly which helps with obtaining time diversity.
• DRX discontinuous reception
• Fig. 9 illustrates a Walsh matrix-based transmission pattern set according to a further embodiment of the present invention.
• the UE 1 uses the 2nd row in the Walsh matrix H 1 ? and the UE 2 uses the 4th row in the first matrix H 2 .
• Np_l , Np_3, Np_(N-l) can be set as 1 , which means there is no gap between two sequential potential transmission subframes.
• Fig. 10 illustrates a UE according to an embodiment of the present invention. As shown in Fig. 10, the UE comprises a unit for
• determining a transmission pattern set a unit for determining one row and a broadcasting unit.
• the unit for determining a transmission pattern set is configured for determining a transmission pattern set, which includes all rows except the first row in a Walsh matrix Hi and a first matrix H 2 , wherein the first matrix H 2 is a product of the Walsh matrix Hi and -1.
• the unit for determining a transmission pattern comprises: a preconfiguring unit, configured for preconfiguring the transmission pattern set at the UE.
• the unit for determining a transmission pattern comprises: a first receiving unit, configured for receiving a first indication message from a base station, the first indication message indicating the transmission pattern set; and a first determining unit, configured for determining the transmission pattern set according to the first indication message.
• the unit for determining one row is configured for determining one row from the transmission pattern set.
• the unit for determining one row comprises: a second receiving unit, configured for receiving a second indication message from a base station, the second indication message indicating the row; and a second determining unit, configured for determining the row from the transmission pattern set based on the second indication message.
• the unit for determining one row comprises: a third determining unit, configured for determining the row according to a predetermined condition.
• the broadcasting unit is configured for implementing a
• Device-to-Device broadcast according to a transmission pattern corresponding to the determined row, wherein the transmission pattern is: implementing the following procedures based on each element in the determined row successively:- transmitting the broadcast when the element is a first value;- receiving the broadcast when the element is a second value.

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

Applications Claiming Priority (2)

Publications (1)

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• 2014
  • 2014-05-08 CN CN201410192977.8A patent/CN105101043B/zh active Active
• 2015
  • 2015-04-22 TW TW104112867A patent/TWI565351B/zh not_active IP Right Cessation
  • 2015-05-04 KR KR1020167034001A patent/KR101915159B1/ko active IP Right Grant
  • 2015-05-04 WO PCT/IB2015/001122 patent/WO2015173644A1/en active Application Filing
  • 2015-05-04 EP EP15766238.8A patent/EP3141067A1/en not_active Withdrawn

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