Background
In the Long Term Evolution (LTE) technology, a low code Rate Time Division duplex (LCR-TDD) Frame structure is written as an LTE TDDType2 Frame structure, as shown in fig. 1, in an LTE TDD Type2 Frame structure, each 10ms (Radio Frame) is divided into two identical Half-frames (Half-frames), each Half-Frame includes 7 regular Time slots (slots) and 3 special Time slots, each regular Time slot TSI (I is greater than or equal to 0 and less than or equal to 6) includes a plurality of Orthogonal Frequency Division Multiplexing (OFDM) symbols, and the use of the special Time slots is the same as that of the original LCR TDD mode: a downlink pilot Time Slot (DwPTS) is used for transmission of a downlink synchronization signal, a Guard Period (GP 1) is used for a Guard Period when downlink transmission is switched to uplink transmission, and an uplink pilot Time Slot (UpPTS) is used for random access of uplink. In the normal time slot, the normal time slot TS0 is used for downlink data transmission, and the TS1 is used for uplink data transmission.
As mentioned above, two pairs of uplink and downlink timeslot switching points are included in each 10ms radio frame, as shown in the figure, a downlink to uplink timeslot switching point DUSP and an uplink to downlink timeslot switching point UDSP in the first 5ms half frame (for uplink and downlink timeslots separated by a switching point, which is also true for DUSP and UDSP), and the same pair of timeslot switching points exists in the second 5ms half frame, and the two pairs of uplink and downlink timeslot switching points correspond to two groups of special timeslots, including two downlink to uplink switching guard intervals GP.
Since the guard interval determines the coverage of the base station, the frame structure shown in fig. 1 has a guard interval GP of 50us in duration, and can only support a coverage of 7.5km (light speed × 50us/2 ═ 7.5 km). In practical application, if the coverage area of the base station needs to be increased, the GP duration needs to be increased. As shown in fig. 2, in the prior art, in order to support a large coverage area of a base station, an original GP may be merged with three timeslots, i.e., UpPTS and TS1, to be a new GP (random access is completed in TS2 and subsequent consecutive uplink timeslots), where the duration is 866.66us, and a coverage area of about 130km can be supported, and then the GP overhead in a radio frame is 17.33% (866.66us/5 ms).
Further, in order to support an ultra-large coverage range of more than 200km, as shown in fig. 3, an original GP may be merged with four timeslots including UpPTS, TS1 and TS2 to serve as a new GP (random access is completed in TS3 and a subsequent continuous uplink timeslot), the duration is 1541.66us, and a coverage range of about 230km can be supported, where the GP overhead in a radio frame is 30.83% (1541.66us/5 ms).
As described above, in the conventional LTE TDD Type2 frame structure, the uplink and downlink timeslot allocation is configured by taking a 5ms field as a period, that is, a pair of uplink and downlink timeslot switching points is set in each 5ms field, and corresponds to a downlink to uplink guard interval GP. According to the Time Division Duplex (TDD) principle, the guard interval duration is proportional to the coverage of the base station. When the existing frame structure supports large coverage or ultra-large coverage, as a longer GP needs to be arranged in each 5ms half frame, the GP overhead is larger, and the data transmission efficiency is reduced.
Disclosure of Invention
The embodiment of the invention provides a method, a system and a device for wireless frame transmission of a time division duplex mobile communication system, which can save the overhead of a guard interval and improve the efficiency of data transmission.
The embodiment of the invention provides a wireless frame transmission method of a time division duplex mobile communication system, which comprises the following steps:
a radio frame period transmitted in a time division duplex mobile communication system includes a pair of uplink and downlink timeslot switching points, and,
in a large coverage scene of a base station, in a transmitted radio frame period, combining the GP of a first half frame with three time slots of UpPTS and TS1 to be used as a new GP; or,
in a scene of overlarge coverage of a base station, in a transmitted radio frame period, the GP of the first half frame is combined with four time slots of UpPTS, TS1 and TS2 to be used as a new GP.
The embodiment of the invention discloses a time division duplex mobile communication system, which comprises,
the configuration module is used for calculating the time length of GP under the coverage area according to the coverage area of the base station, selecting the radio frame structure configuration corresponding to the GP time length, and informing the base station to receive and transmit data according to the frame structure configuration, wherein the radio frame comprises a pair of uplink and downlink time slot switching points in a period, and in a large coverage scene of the base station, the GP of a first half frame is combined with three time slots of UpPTS and TS1 to be used as a new GP in the transmitted radio frame period; or, in a super-large coverage scene of the base station, in a transmitted radio frame period, combining the GP of the first half frame with four time slots of UpPTS, TS1 and TS2 to serve as a new GP;
and the base station is used for transmitting data or control signaling according to the wireless frame configured by the configuration module.
The base station provided by the embodiment of the invention comprises a sending unit and a receiving unit,
the sending unit is used for sending downlink data or control signaling to the user terminal through a wireless frame;
the receiving unit is used for receiving uplink data or control signaling sent by the user terminal through a wireless frame and receiving frame structure configuration signaling sent by the configuration module;
the radio frame comprises a pair of uplink and downlink time slot switching points in one period, and the GP time length from downlink to uplink switching can be configured.
The configuration module provided by the embodiment of the invention comprises a computing unit and a communication unit,
the calculation unit is used for calculating the time length of the GP according to the coverage area of the base station and selecting the frame structure configuration corresponding to the time length of the GP;
and the communication unit is used for informing the frame structure configuration to a base station and a user terminal.
The user terminal provided by the embodiment of the invention comprises a sending unit and a receiving unit,
the sending unit is used for sending uplink data or control signaling to the base station through a wireless frame,
the receiving unit is used for receiving downlink data or control signaling sent by the base station through a wireless frame and receiving frame structure configuration signaling sent by the configuration module;
the radio frame comprises a pair of uplink and downlink time slot switching points in one period, and the GP time length from downlink to uplink switching can be configured.
The embodiment of the invention discloses a time division duplex mobile communication system, which comprises,
the base station is used for sending downlink data or control signaling to the user terminal through a wireless frame and receiving uplink data or control signaling sent by the user terminal through the wireless frame;
the user terminal is used for sending uplink data or control signaling to the base station through the wireless frame and receiving downlink data or control signaling sent by the base station through the wireless frame;
the wireless frame comprises a pair of uplink and downlink time slot switching points in one period.
The base station provided by the embodiment of the invention comprises a sending unit and a receiving unit,
the sending unit is used for sending downlink data or control signaling to the user terminal through a wireless frame;
the receiving unit is configured to receive uplink data or a control signaling sent by a user terminal through a radio frame, where the radio frame includes a pair of uplink and downlink timeslot switching points in one period.
The user terminal provided by the embodiment of the invention comprises a sending unit and a receiving unit,
the sending unit is used for sending uplink data or control signaling to the base station through a wireless frame,
the receiving unit is configured to receive downlink data or a control signaling sent by a base station through a radio frame, where the radio frame includes a pair of uplink and downlink timeslot switching points in one period.
The embodiment of the invention sets a pair of uplink and downlink time slot switching points in a radio frame period, and under the scenes of large coverage and overlarge coverage of a base station, because downlink data and uplink data only need to be switched once in the radio frame period, the GP overhead of switching the guard interval is effectively saved, and the transmission efficiency of the radio frame is improved.
Detailed Description
The embodiment of the invention allocates the uplink and downlink time slots by taking a wireless frame as a period, and can effectively save the overhead of a guard interval and improve the efficiency of wireless frame transmission when the coverage area of a base station is enlarged by arranging a pair of uplink and downlink time slot switching points in the wireless frame period.
In the LTE TDD Type2 frame structure, a fixed time length of a radio frame is 10ms, the radio frame comprises two half frames with the time length of 5ms, only one pair of uplink and downlink time slot switching points is arranged in the whole 10ms radio frame and corresponds to a downlink-to-uplink guard interval GP, when the coverage area of a base station is enlarged and the time length of the GP needs to be increased, the overhead of the guard interval can be effectively saved, and the radio frame transmission efficiency is improved.
In the LTE TDD Type2 frame structure, only one pair of uplink and downlink TimeSlot switching points is set in the whole 10ms radio frame, including setting one downlink to uplink TimeSlot switching point in the first 5ms half frame, corresponding to one downlink to uplink guard interval, setting the position of the second switching point according to the configuration of the cell uplink and downlink timeslots, and combining three special timeslots (downlink pilot TimeSlot DwPTS, guard interval GP, uplink pilot TimeSlot UpPTS) into one Short TimeSlot (Short TimeSlot slot) in the second 5ms half frame, for the transmission of uplink/downlink data or control signaling.
In the manner provided by the embodiment of the invention, the GP overhead is 50% of the GP overhead under the frame structure in the prior art. As described in the following description, the embodiments provided by the present invention mainly reflect that only one pair of up-and-down slot switching points is set in a cycle of a 10ms radio frame, so as to improve the transmission efficiency of radio frame data in a large coverage scenario.
The following description of the embodiments of the present invention is provided in connection with the accompanying drawings.
Referring to fig. 4, fig. 4 is a frame structure diagram of a pair of switching points in a 10ms radio frame according to an embodiment of the present invention. In the embodiment of the present invention, the 10ms radio frame is divided into two 5ms fields, including a first 5ms field and a second 5ms field. In a 10ms radio frame, there is only one pair of switching points, including a downlink-to-uplink timeslot switching point DUSP and an uplink-to-downlink timeslot switching point UDSP, corresponding to a downlink-to-uplink guard interval GP, and in the second 5ms half frame, three special timeslots are combined into one short timeslot TS for transmitting data or control signaling.
As shown in fig. 4, the guard interval GP is 50us long and can only support a coverage of 7.5 km. In practical application, in order to support a large coverage area of a base station, the time length of the guard interval GP needs to be increased, and a way of increasing the time length of the GP can be implemented by combining the GP, the UpPTS and the conventional timeslot as a new guard interval GP.
The following is a method for setting a guard interval with 10ms as a slot allocation period in a large coverage scenario of a base station, where the large coverage scenario of the base station refers to a range where the base station covers about 130km, and this embodiment is described as a range where the base station covers 130km, as shown in fig. 5:
allocating uplink and downlink time slots in a 10ms radio frame as a period, wherein the 10ms radio frame period comprises: a first 5ms field and a second 5ms field. The first 5ms half frame comprises seven conventional time slots TSI, wherein I belongs to an integer of {0, 1,....... 6} and three special time slots, namely a downlink pilot time slot DwPTS, a guard interval GP and an uplink pilot time slot UpPTS, and the GP of the first 5ms half frame, the UpPTS and the TS1 are combined to be used as a new GP with the time length of 866.66 us; the second 5ms half frame includes seven conventional time slots TSI, I ∈ {0, 1,..., 6} integer, three special time slots, namely, a downlink pilot time slot DwPTS, a guard interval GP, and an uplink pilot time slot UpPTS, and combines the three special time slots DwPTS, GP, and UpPTS to form a short time slot, which may transmit data or control signaling.
The process of switching between uplink and downlink data within a 10ms radio frame is described further below.
In the first 5ms half frame, TS0 is used as a downlink time slot to transmit downlink data, the duration of a new GP is 866.66us, a 130km coverage range is supported, DUSP is a time slot switching point from downlink to uplink, the switching from the downlink data to the uplink data is completed, random access is completed in TS2 and subsequent continuous uplink time slots, and TS 2-TS 6 are used as uplink time slots to transmit uplink data; and in the second 5ms half frame TS0 and the short time slot TS, the switching from the uplink time slot to the downlink time slot is completed through an uplink-to-downlink time slot switching point UDSP, TS 1-TS 6 are used as downlink time slots, and then, the transmission of the data of the next 10ms wireless frame is carried out.
Since the GP is not consumed for the uplink-to-downlink timeslot switching, the location of the UDSP is not limited by this embodiment, as long as all locations of the uplink-to-downlink timeslot switching point that meet the spirit of the present invention are included within the scope of the present invention.
The following further describes a method for setting a guard interval by using 10ms as a time slot allocation period in a super-large coverage scenario of a base station, where the super-large coverage scenario of the base station refers to a range covered by the base station for about 230km, and this embodiment is described by using the range covered by the base station for 230km, as shown in fig. 6:
allocating uplink and downlink time slots in a 10ms radio frame as a period, wherein the 10ms radio frame period comprises: a first 5ms field and a second 5ms field. The first 5ms half frame comprises seven conventional time slots TSI, wherein I belongs to an integer of {0, 1,....... 6} and three special time slots, namely a downlink pilot time slot DwPTS, a guard interval GP and an uplink pilot time slot UpPTS, the GP of the first 5ms half frame is combined with four time slots, namely the UpPTS, TS1 and TS2 to form a new GP, and the time length is 1541.66 us; the second 5ms half frame includes seven conventional time slots TSI, I ∈ {0, 1,..., 6} integer, three special time slots, namely, a downlink pilot time slot DwPTS, a guard interval GP, and an uplink pilot time slot UpPTS, and combines the three special time slots DwPTS, GP, and UpPTS to form a short time slot, which may transmit data or control signaling.
The process of switching between uplink and downlink data within a 10ms radio frame is described further below.
In the first 5ms half frame, TS0 is used as a downlink time slot, the duration of a new GP is 1541.66us, a coverage range of 230km is supported, DUSP is a time slot switching point from downlink to uplink, switching from downlink data to uplink data is completed, random access is completed in TS3 and subsequent continuous uplink time slots, and TS 3-TS 6 are used as uplink time slots; and in the second 5ms half frame TS0 and the short time slot TS, the switching from the uplink time slot to the downlink time slot is completed through an uplink-to-downlink time slot switching point UDSP, TS 1-TS 6 are used as downlink time slots, and then, the transmission of the data of the next 10ms wireless frame is carried out.
Since the GP is not consumed for the uplink-to-downlink timeslot switching, the location of the UDSP is not limited by this embodiment, as long as all locations of the uplink-to-downlink timeslot switching point that meet the spirit of the present invention are included within the scope of the present invention.
As shown in fig. 7, a time division duplex mobile communication system according to an embodiment of the present invention includes a base station, a configuration module, and a user terminal.
The base station is used for sending downlink data or control signaling to the user terminal through a wireless frame, sending base station coverage signaling to the configuration module, receiving uplink data or control signaling sent by the user terminal through the wireless frame, and receiving frame structure configuration signaling sent by the configuration module;
the configuration module is used for calculating the time length of GP under the coverage range according to the coverage range of the base station, selecting the corresponding frame structure configuration according to the time length of GP, and informing the frame structure configuration to the base station and the user terminal through a broadcast channel so that the base station and the user terminal receive and transmit data according to the frame structure configuration;
and the user terminal is used for sending uplink data or control signaling to the base station through the wireless frame, receiving downlink data or control signaling sent by the base station through the wireless frame, and receiving the frame structure configuration signaling of the configuration module.
The radio frame comprises a pair of uplink and downlink time slot switching points in one period, and the GP time length from downlink to uplink switching can be configured.
The base station of the embodiment of the invention comprises a sending unit and a receiving unit. The sending unit is used for sending downlink data or a control signaling to the user terminal through a wireless frame, the receiving unit is used for receiving uplink data or a control signaling sent by the user terminal through the wireless frame, and receiving a frame structure configuration signaling sent by the configuration module, the wireless frame comprises a pair of uplink and downlink time slot switching points in one period, and the GP time length from downlink to uplink switching can be configured.
The configuration module of the embodiment of the invention comprises a computing unit and a communication unit. The communication unit is configured to notify the frame structure configuration to the base station and the user terminal.
The user terminal of the embodiment of the invention comprises a sending unit and a receiving unit. The sending unit is used for sending uplink data or control signaling to the base station through a wireless frame, the receiving unit is used for receiving downlink data or control signaling sent by the base station through the wireless frame and receiving frame structure configuration signaling sent by the configuration module, the wireless frame comprises a pair of uplink and downlink time slot switching points in one period, and the GP time from downlink to uplink switching can be configured.
As shown in fig. 8, a time division duplex mobile communication system according to an embodiment of the present invention includes a base station and a user terminal.
The base station is used for sending downlink data or control signaling to the user terminal through a wireless frame and receiving uplink data or control signaling sent by the user terminal through the wireless frame;
the user terminal is used for sending uplink data or control signaling to the base station through the wireless frame and receiving downlink data or control signaling sent by the base station through the wireless frame;
the radio frame comprises a pair of uplink and downlink time slot switching points in one period.
The base station of the embodiment of the invention comprises a sending unit and a receiving unit. The sending unit is used for sending downlink data or control signaling to the user terminal through a wireless frame, the receiving unit is used for receiving uplink data or control signaling sent by the user terminal through the wireless frame, and the wireless frame comprises a pair of uplink and downlink time slot switching points in one period.
The user terminal of the embodiment of the invention comprises a sending unit and a receiving unit. The sending unit is used for sending uplink data or control signaling to the base station through a wireless frame, the receiving unit is used for receiving downlink data or control signaling sent by the base station through the wireless frame, and the wireless frame comprises a pair of uplink and downlink time slot switching points in one period.
As shown in table 1 below, for the comparison of GP overheads in different coverage areas with a 5ms half-frame as an allocation period and a 10ms radio frame as an allocation period, it can be seen that, as the coverage area increases, the GP overheads can be effectively saved by using the 10ms radio frame as the allocation period, thereby improving the radio frame transmission efficiency.
TABLE GP overhead comparison of 15ms and 10ms slot allocation periods under different coverage
In summary, the embodiments of the present invention have the beneficial effects that, in a scenario of large coverage and ultra-large coverage of a base station, downlink data and uplink data only need to be switched once in a radio frame period, so that overhead of switching a guard interval GP is effectively saved, and radio frame transmission efficiency is improved.
It should be understood that the above description is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily made by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.