CN101867948B - Method for sending downlink intermediate pilot in wireless communication system - Google Patents
Method for sending downlink intermediate pilot in wireless communication system Download PDFInfo
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- H04—ELECTRIC COMMUNICATION TECHNIQUE
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- H04W72/23—Control channels or signalling for resource management in the downlink direction of a wireless link, i.e. towards a terminal
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Abstract
The invention discloses a method for sending a downlink intermediate pilot in a wireless communication system. A base station sends the intermediate pilot on one or two of third, fourth and seventh symbols in a downlink sub-frame. When the sending antenna number of the base station is 2 or 4, the base station sends the intermediate pilot on the third or fourth or seventh symbol in the downlink sub-frame. When the sending antenna number of the base station is 8, the base station sends the intermediate pilot on the third and fourth symbols or the third and seventh symbols or the fourth and seventh symbols in the downlink sub-frame. The method for sending the intermediate pilot can accurately measure the real channel condition of the downlink when the special pilot is used at a terminal so as to finish feedback of pre-code matrix indication (PMI), rank indication (RI) and channel quality information (CQI). Meanwhile, the method of the invention has lower complexity and good pilot tracking capability.
Description
Technical Field
The invention belongs to the technical field of wireless communication, and particularly relates to a method for sending downlink intermediate pilot frequency in a wireless communication system.
Background
Many new technologies, such as Orthogonal Frequency Division Multiplexing (OFDM) and Multiple-input Multiple-Output (MIMO), have appeared in the field of wireless communication, which can greatly improve the performance of the communication system, thereby meeting the ever-increasing data service requirements. In order to further improve the transmission quality, the data stream and the pilot frequency coded by MIMO may be precoded and then mapped to different antennas for transmission. Thus, the dedicated pilots are also present. In an MIMO system using a special pilot frequency mode, an equivalent channel after precoding is obtained by utilizing channel estimation, and for a system needing to feed back the real channel condition, the equivalent channel is very complicated or even cannot be converted into the real channel; in addition, the real channel condition cannot be periodically obtained for a terminal without any data transmission for a period of time. For this reason, a method is needed to measure the current real channel condition to meet the feedback requirement of the system.
The intermediate pilot is a specific pilot sequence inserted into a certain symbol in a frame for performing channel measurement at the receiving end. The channels of all carrier positions on the whole symbol can be estimated by using the intermediate pilot frequency, so that a transmitting end can reasonably adopt an efficient transmission strategy according to the current channel condition.
In a wireless communication system, it is reasonable to measure a real Channel condition by using an intermediate pilot, and to accurately feed back Channel Quality Information (CQI), a Precoding Matrix Index (PMI), and a Rank Indication (RI), which are important for improving transmission efficiency of the system.
Therefore, how to select a proper timing to transmit the intermediate pilot and what format of the intermediate pilot is to be transmitted to achieve a better channel measurement effect are issues that must be considered by a technician.
Disclosure of Invention
The technical problem to be solved by the present invention is to provide a method for transmitting downlink intermediate pilot in a wireless communication system, so that a terminal can achieve a better channel measurement effect.
In order to solve the above technical problem, the present invention provides a method for transmitting a downlink intermediate pilot in a wireless communication system, including:
and the base station transmits the intermediate pilot on one or two symbols in the third, fourth or seventh symbol in the downlink subframe.
Preferably, when the number of transmit antennas of the base station is 2 or 4, the base station transmits the intermediate pilot on the third or fourth or seventh symbol in the downlink subframe.
Preferably, when the number of transmit antennas of the base station is 8, the base station transmits a pilot on the third and fourth symbols or the third and seventh symbols or the fourth and seventh symbols in the downlink subframe.
In order to solve the above technical problem, the present invention further provides a method for transmitting a downlink intermediate pilot in a wireless communication system, including: the base station sends a message to inform the user terminal of the position of the intermediate pilot frequency in the downlink frame through a broadcast control channel and/or a unicast control channel.
Preferably, the message includes:
whether the current frame or the super frame has the intermediate pilot frequency and/or the frame and/or subframe index to which the intermediate pilot frequency symbol belongs; or,
the base station transmits the intermediate pilot frequency in a period T frame at a continuous S frame which is shifted backwards by delta S frame from a frame where the current message is positioned, and transmits a message informing a terminal of a sub-frame index to which an intermediate pilot frequency symbol belongs through a broadcast control channel and/or a unicast control channel at the frame which correspondingly transmits the intermediate pilot frequency;
where Δ S, S, T is a natural number.
In order to solve the above technical problem, the present invention further provides a method for transmitting a downlink intermediate pilot in a wireless communication system, including:
the base station sends the intermediate pilot frequency in one or more subframes except the first subframe in the downlink frame;
or the base station sends the intermediate pilot frequency in one or more subframes except the first subframe of one downlink frame of the downlink superframe.
Preferably, the base station sends the intermediate pilot in the last downlink subframe of the downlink frame, or the base station sends the intermediate pilot in the last subframe of a downlink frame of the downlink superframe.
Preferably, when the terminal accesses, the base station notifies the terminal of the position of the downlink subframe where the base station sends the intermediate pilot frequency through the access control related message.
Preferably, the base station sends a message to inform the terminal whether the current super frame and/or frame sends the intermediate pilot frequency through a broadcast control channel and/or a unicast control channel, and if so, the base station sends the intermediate pilot frequency on the determined downlink frame and/or sub frame.
The method of the invention is adopted to send the intermediate pilot frequency, which can accurately measure the real channel condition of the downlink when the terminal uses the special pilot frequency, and complete the feedback of PMI, RI and CQI. Meanwhile, the method of the invention has lower complexity and good pilot frequency tracking capability.
Drawings
Fig. 1 is a schematic diagram of data and pilot frequency distribution in a basic Resource block (Resource Unit, RU for short) of a downlink subframe in the 802.16m standard.
Fig. 2 is a flowchart of an intermediate pilot transmission method according to the present invention.
FIG. 3(a) example 1A basic resource block middle pilot insertion pattern diagram
FIG. 3(b) example 2A diagram of a basic resource block pilot insertion pattern
Fig. 4(a) is a diagram of a basic resource block middle pilot insertion pattern corresponding to example 3.
Fig. 4(b) is a diagram of a basic resource block middle pilot insertion pattern corresponding to example 4.
Fig. 5(a) -5 (c) are diagrams of a basic resource block middle pilot insertion pattern corresponding to example 5.
FIG. 6(a) is a diagram of pilot insertion pattern in the middle of a basic resource block corresponding to example 6
Fig. 6(b) is a diagram of a basic resource block middle pilot insertion pattern corresponding to example 7.
Fig. 7(a) -fig. 7(c) are diagrams of a basic resource block middle pilot insertion pattern corresponding to example 8.
FIGS. 8(a) -8 (b) show a basic resource block middle pilot insertion pattern corresponding to example 9
Fig. 9(a) -9 (b) are diagrams of a basic resource block middle pilot insertion pattern corresponding to example 10.
Fig. 10(a) -10 (b) are diagrams of a basic resource block middle pilot insertion pattern corresponding to example 11.
Fig. 11(a) -11 (b) are diagrams of a basic resource block middle pilot insertion pattern corresponding to example 12.
Detailed Description
The main idea of the present invention is to select a downlink frame and a downlink subframe to be transmitted with intermediate pilot, and after selecting to remove all data demodulation pilot on each symbol in the downlink subframe, one symbol with the largest number of remaining carriers (at this time, the number of transmit antennas of the base station is 2 or 4) or two consecutive symbols (at this time, the number of transmit antennas of the base station is 8) is transmitted with intermediate pilot.
The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments.
Referring to fig. 1, a schematic diagram of data and pilot frequency distribution in a basic resource block (resource unit, RU for short) of a downlink subframe in the 802.16m standard is shown.
According to the specification of the 802.16m standard, the structure of a basic resource block is as follows: comprising 5 or 6 or 7 OFDM symbols in the time direction and 18 subcarriers in the frequency direction. Fig. 1 shows a basic resource block structure including 6 OFDM symbols in the time direction, in which black squares represent data demodulation pilots and white squares represent data regions. As can be seen from the structure of the basic resource block shown in fig. 1, the 3 rd and 4 th symbols in the basic resource block are the symbols with the least number of subcarriers occupied by the data demodulation pilots (i.e., black squares), and the present invention considers transmitting the intermediate pilots on these symbols.
Referring to fig. 2, a flowchart of an intermediate pilot transmission method according to the present invention is shown. The method comprises the following steps:
step 201: determining a downlink frame and a downlink subframe for transmitting the intermediate pilot frequency;
step 202: selecting one symbol or two continuous symbols with the maximum number of residual carriers after removing all data demodulation pilot frequencies on each symbol in the downlink subframe;
step 203: determining the carrier position of the symbol or two continuous symbols for transmitting the intermediate pilot frequency in the frequency direction;
step 204: intermediate pilots are inserted at the carrier locations.
For the 802.16m standard, when a basic resource block is structured to include 5 and 6 OFDM symbols in the time direction, the symbol with the minimum number of subcarriers occupied by the data demodulation pilot is the 3 rd and 4 th symbols, and when a basic resource block is structured to include 7 OFDM symbols in the time direction, the symbol with the minimum number of subcarriers occupied by the data demodulation pilot is the 3 rd, 4 th and 7 th symbols.
The determining the downlink frame for sending the intermediate pilot in step 201 includes:
the base station indicates the terminal to send the downlink subframe position of the middle pilot frequency through the broadcast message; or the base station sends the intermediate pilot frequency in a preset downlink subframe or the two modes are combined to indicate the position of the downlink subframe where the terminal sends the intermediate pilot frequency.
The predetermined downlink subframe may be any other subframe except the first subframe in the downlink frame.
Specifically, the present invention provides an intermediate pilot configuration mode for channel measurement in downlink of 802.16m wireless communication system, which mainly comprises the following steps:
in a downlink frame of an 802.16m wireless communication system, a base station selects symbols of j (j is a natural number smaller than the maximum downlink subframe number contained in the frame) subframes of an ith downlink frame to transmit intermediate pilot.
Specifically, the base station sends the intermediate pilot frequency in one or more subframes except the first subframe in the downlink frame; or the base station sends the intermediate pilot frequency in one or more subframes except the first subframe of one downlink frame of the downlink superframe.
Preferably, the determined downlink subframe for transmitting the intermediate pilot is the last subframe in a downlink frame. Or the base station sends the intermediate pilot frequency in the last subframe of a downlink frame of the downlink superframe. When the terminal is accessed, the base station informs the terminal of the position of the downlink subframe of the intermediate pilot frequency sent by the base station through the access control related message. In each downlink frame, the base station sends a message through a broadcast control channel and/or a unicast control channel to inform the terminal whether the current frame sends the intermediate pilot frequency, and if the current frame sends the intermediate pilot frequency, the base station sends the intermediate pilot frequency on the determined downlink subframe.
The base station sends a message to inform the user terminal of the position of the intermediate pilot frequency in the downlink frame through a broadcast control channel and/or a unicast control channel.
The message comprises: whether the current frame or the super frame has the intermediate pilot frequency and/or the frame and/or subframe index to which the intermediate pilot frequency symbol belongs; or,
the base station transmits the intermediate pilot frequency in a period T frame at a continuous S frame which is shifted backward by delta S frame from a frame where the current message is positioned, and transmits a message informing the terminal of the sub-frame index to which the intermediate pilot frequency symbol belongs through a broadcast control channel and/or a single-wave control channel at the frame which correspondingly transmits the intermediate pilot frequency. Where Δ S, S, T is a natural number.
The message transmitted through the unicast control channel is a non-user specific message (non-user specific message) message of a downlink frame.
The criterion used by the base station when selecting the time domain symbol index for placing the middle pilot frequency in the subframe is as follows: after removing all the data demodulation pilots on each symbol (shown in fig. 1), the middle pilot is transmitted by one symbol (the number of transmit antennas of the base station is 2 or 4) or two consecutive symbols (the number of transmit antennas of the base station is 8) with the largest number of remaining carriers. That is, when the number of the transmitting antennas of the base station is 2 or 4, the base station selects the third or fourth or seventh symbol in the determined downlink subframe to transmit the intermediate pilot; and when the number of the transmitting antennas of the base station is 8, the base station selects the third symbol and the fourth symbol in the determined downlink subframe to transmit the middle pilot frequency.
When the number of the base station transmitting antennas is more than 4 and less than or equal to 8, each symbol in the two symbols for transmitting the intermediate pilot frequency transmits the intermediate pilot frequency corresponding to 4 different antennas.
The criterion used by the base station in determining the frequency domain carrier position index (sequence number) for placing the middle pilot frequency in the subframe is as follows:
when the number of the transmitting antennas is 2 or 4, the relative position index Set of the middle pilot Carrier corresponding to the (n + 1) th antenna (n is more than or equal to 0 and less than or equal to 3) in the basic resource block is Midamble _ Carrier _ Set _ PRU:
Midamble_Carrier_Set_PRU＝3+n+k1Δs
wherein k is1＝0，1，2，…K1-1, index of intermediate pilot on basic resource block; k1Representing the number of intermediate pilots inserted in one resource block by each antenna; Δ s is the number of carrier spacing between two adjacent pilots within each basic resource block per antenna.
When the intermediate pilot is inserted over the full bandwidth, the occupied physical Carrier position index Midamble _ Carrier _ Set is:
in which the dc sub-carriers (zero carriers) are included at the time of sorting, but are removed in advance at the time of transmission. The following examples are the same.
When the middle pilot frequency is inserted in partial resource block on the full bandwidth, the index of occupying physical Carrier position, Midamble _ Carrier _ Set, is
Wherein k is2＝0，1，2，…K2-1, index of the intermediate pilot over full bandwidth; k2Representing the number of intermediate pilots inserted on the system bandwidth by each antenna; Δ s is the carrier spacing number between two adjacent pilot frequencies in the basic resource block of each antenna; m is the number of the middle pilot frequencies of each antenna in each basic resource block;is expressed as being equal to or less thanMaximum ofInteger, mod (k)2M) represents k2The remainder of the whole division by m; n is a radical ofusedRepresenting the number of all the subcarriers left after the system removes the subcarriers of the guard interval at two sides, i belongs to {0,1,2, … M } as the basic resource block logic index set inserted with the middle pilot frequency, SiAnd the physical position index corresponding to the first subcarrier of the ith resource block inserted with the middle pilot frequency is shown.
The logical index means that the physical indexes of all the M +1 basic resource blocks inserted with the middle pilot frequency are arranged from 0 to M according to the sequence from small to large, and the corresponding sequence number of the basic resource block is the logical index.
When the number of the transmitting antennas of the base station is 8, the relative position index Set of the middle pilot Carrier corresponding to the (n + 1) th antenna (n is more than or equal to 0 and less than or equal to 7) in each basic resource block is Midamble _ Carrier _ Set _ PRU:
or
Midamble_Carrier_Set_PRU＝3+mod(n，4)+k1Δs；
Wherein the middle pilot frequency of 4 antennas is on the sub-carrier corresponding to one symbol of the two symbols, and the middle pilot frequency of the other 4 antennas is on the sub-carrier corresponding to the other symbol of the two symbols.
And
when the intermediate pilot is inserted over the full bandwidth, the occupied physical Carrier position index Midamble _ Carrier _ Set is:
or
(ii) a And
when the middle pilot frequency is inserted in partial resource block on the full bandwidth, the index of occupying physical Carrier position, Midamble _ Carrier _ Set, is
Wherein k is1＝0，1，2，…K1-1, index of intermediate pilot on basic resource block; k1Representing the number of intermediate pilots inserted in one resource block by each antenna; k is a radical of2＝0，1，2，…K2-1, index over full bandwidth for the intermediate pilot for each antenna; k2Representing the number of intermediate pilots inserted on the system bandwidth by each antenna; m is the number of the middle pilot frequencies of each antenna in each basic resource block; Δ s is the number of carrier intervals between two adjacent pilot frequencies of each antenna;is expressed as being equal to or less thanThe smallest integer of (a); n is a radical ofusedRepresenting the number of all the remaining subcarriers after the system removes the subcarriers of the guard interval at two sides; i ∈ {0,1,2, … M } is a basic resource block logical index set, S, into which intermediate pilots are insertediAnd the physical position index corresponding to the first subcarrier of the ith resource block inserted with the middle pilot frequency is shown.
The logical index means that the physical indexes of all the M +1 basic resource blocks inserted with the middle pilot frequency are arranged from 0 to M according to the sequence from small to large, and the corresponding sequence number of the basic resource block is the logical index.
Further optimization, in order to avoid mutual interference of the intermediate pilots of the adjacent cells, the adjacent cells select the same sub-frame of different frames to transmit the intermediate pilots, or the different sub-frames of the same frame to transmit the intermediate pilots, or the different symbols of the same sub-frame to transmit the intermediate pilots.
Further optimally, when the adjacent cells transmit the intermediate pilot on the same symbol of the same subframe, the adjacent cells adopt different code sequences as pilot signals, thereby avoiding interference between the cells.
Further, when the adjacent cells transmit the intermediate pilot on the same symbol of the same subframe, if the base station has 2 transmit antennas, the adjacent cells insert the intermediate pilot in a frequency division multiplexing manner.
The frequency division multiplexing refers to that different carrier sets in the same symbol frequency domain in the basic resource block are selected by adjacent cells to transmit intermediate pilot frequency, and the pilot carrier set used in each basic resource block of the adjacent three cells and the physical position index set of the intermediate pilot carrier with full bandwidth are respectively as follows:
cell 1:
Midamble_Carrier_Set_PRU＝3+n+k1Δs
cell 2 uses a carrier set:
Midamble_Carrier_Set_PRU＝3+n+k1Δs+ΔBS
cell 3 uses a carrier set:
Midamble_Carrier_Set_PRU＝3+n+k1Δs+2ΔBS
wherein ΔBSThe number of carrier intervals of the middle pilot frequency in the frequency domain in each basic resource block of the adjacent cell.
The terminal comprises a relay station, a mobile phone, a notebook computer and other terminals which can realize channel measurement according to the intermediate pilot frequency.
The technical solution of the present invention is exemplified by the following examples in specific applications. In order to make the technical solution of the present invention easier to understand, the technical solution of the present invention is explained by 18 application examples below. Of course, there are many embodiments without limitation, but the embodiments are only illustrated in the following due to limited space.
Example 1:
this example is used to illustrate the position of the middle pilot in the basic resource block when the base station configures 2 transmit antennas: the position of the middle pilot frequency in the subframe is on the fourth symbol of the subframe. Fig. 3(a) shows only the carrier position of the 4 th symbol occupied by the middle pilot when the basic resource block structure is 18 × 6, and the carrier position of the 4 th symbol occupied by the middle pilot is the same as the position described below when the basic resource block structure is 18 × 7. The carrier positions occupied by the intermediate pilots are explained in detail below.
In fig. 3(a)18 × 6, the middle pilot is inserted in the fourth symbol, where P1 is the middle pilot of antenna 1 and P2 is the middle pilot of antenna 2.
Example 2:
this example is used to illustrate the position of the middle pilot in the basic resource block when the base station configures 2 transmit antennas: the position of the middle pilot in the subframe is on the third symbol of the subframe. Fig. 3(b) shows only the carrier position of the 3 rd symbol occupied by the middle pilot when the basic resource block structure is 18 × 6, and the carrier position of the 3 rd symbol occupied by the middle pilot is the same as the position described below when the basic resource block structure is 18 × 7 or 18 × 5. The carrier positions occupied by the intermediate pilots are explained in detail below.
The carrier positions occupied by the intermediate pilots are specifically described below with a subframe structure of 18 × 6.
Fig. 3(b) shows the transmission position of the middle pilot of the basic resource block 18 × 6, and the middle pilot is inserted on the third symbol, where P1 is the middle pilot of antenna 1 and P2 is the middle pilot of antenna 2.
Example 3
This example is used to illustrate the location of the middle pilot in the basic resource block when the base station configures 4 transmit antennas: the position of the middle pilot in the subframe is on the fourth symbol of the subframe. Fig. 4(a) shows only the carrier position of the 4 th symbol occupied by the middle pilot when the basic resource block structure is 18 × 6, and the carrier position of the 4 th symbol occupied by the middle pilot is the same as the position described below when the basic resource block structure is 18 × 7. The carrier positions occupied by the intermediate pilots are explained in detail below.
Fig. 4(a) shows the transmission position of the middle pilot of 18 × 6 basic resource blocks, and the middle pilot is inserted in the fourth symbol, where P1 is the middle pilot of antenna 1, P2 is the middle pilot of antenna 2, P3 is the middle pilot of antenna 3, and P4 is the middle pilot of antenna 4.
Example 4
This example is used to illustrate the location of the middle pilot in the basic resource block when the base station configures 4 transmit antennas: the position of the middle pilot frequency in the subframe is on the third symbol of the subframe. Fig. 4 only shows that the middle pilot occupies the carrier position of the third symbol when the basic resource block structure is 18 × 6, and the carrier position of the third symbol when the basic resource block structure is 18 × 5 or 18 × 7 is the same as that described below. The carrier positions occupied by the intermediate pilots are explained in detail below.
Fig. 4(b) shows the transmission positions of the middle pilots of the basic resource block structure with 4 antennas, which are also inserted in the third symbol, where P1 is the middle pilot of antenna 1, P2 is the middle pilot of antenna 2, P3 is the middle pilot of antenna 3, and P4 is the middle pilot of antenna 4.
Example 5
This example is used to illustrate that when a base station is configured with 2 transmit antennas, adjacent base stations use frequency division multiplexing to avoid interference between adjacent cells.
Referring to fig. 5(a) -5 (c), a diagram of an intermediate pilot insertion pattern corresponding to example 5 is shown.
In this example, a basic resource block is structured to include 6 OFDM symbols in the time direction, and according to the method of transmitting the intermediate pilot of the present invention, the intermediate pilot is transmitted on the third or fourth symbol in the downlink. (only the case where the fourth symbol is transmitted is shown in the figure).
In this embodiment, when the basic resource block structure is 18 × 5 (frequency × time domain), the middle pilot is placed on the third symbol, and when the basic resource block structure is 18 × 6 or 18 × 7 (frequency × time domain), the middle pilot is placed on the third or fourth symbol, and the basic resource block of 18 × 6 corresponds to the carrier position occupied by the middle pilot when the middle pilot is placed on the 4 th symbol, which is described below with reference to fig. 5. When the intermediate pilot is placed on the 3 rd symbol, the carrier position occupied by the intermediate pilot is the same as in the present embodiment.
Fig. 5(a) shows an insertion manner of the intermediate pilot in the sub-frame structure of 2 antennas of the base station 1, where the intermediate pilot is inserted in the fourth symbol, and the interval between adjacent pilots of each antenna is 8 subcarriers, in the figure, P1 is the intermediate pilot of antenna 1, and P2 is the intermediate pilot of antenna 2. Fig. 5(b) and 5(c) are transmission positions of the intermediate pilots of the neighboring base stations 2 and 3, respectively, which are similar to fig. 5(a), and the same intermediate pilots of the base stations 2 and 3 are spaced from the base station 1 by 2 and 4 subcarriers, respectively. In this way, three adjacent cells insert pilot at different sub-carrier positions of the same symbol, and the intermediate pilot interval of the adjacent base stations is 2, which is orthogonal in frequency, so that the channel condition can be measured with less overhead.
Example 6
This example is used to illustrate the situation when the base station is configured with 2 transmit antennas and the sub-frame has 7 time domain symbols, the middle pilot is placed on the 7 th symbol.
Referring to fig. 6(a), a pattern diagram is inserted in a basic resource block for the intermediate pilots corresponding to example 6.
Taking fig. 6(a) as an example to illustrate the case of 2 antennas respectively, fig. 6(a) is an insertion manner of the middle pilot of each basic resource block under the sub-frame structure of 2 antennas, the middle pilot is inserted on the seventh symbol, and the adjacent middle pilot interval of each antenna is 2 subcarriers, where P1 is the middle pilot of antenna 1, and P2 is the middle pilot of antenna 2.
Example 7
This example is used to illustrate the situation when the base station is configured with 4 transmit antennas and the sub-frame has 7 time domain symbols, the middle pilot is placed on the 7 th symbol.
Referring to fig. 6(b), a diagram of an intermediate pilot insertion pattern corresponding to example 7 is shown.
Taking fig. 6(b) as an example to illustrate the case of 4 antennas, fig. 6(b) is an insertion manner of the basic resource block middle pilots of 4 antennas, and the adjacent middle pilot interval of each antenna is 4 subcarriers, where P1 is the middle pilot of antenna 1, P2 is the middle pilot of antenna 2, P3 is the middle pilot of antenna 3, and P4 is the middle pilot of antenna 4.
Example 8
This example is used to illustrate the situation when a base station has 2 antennas and places the intermediate pilots on the 7 th symbol of a sub-frame with 7 time domain symbols, while the neighboring base stations avoid the interference of the mutual intermediate pilots by means of frequency division.
Referring to fig. 7(a) -7 (c), a diagram of an intermediate pilot insertion pattern corresponding to example 8 is shown. In this example, a basic resource block is structured to include 7 OFDM symbols in the time direction, and the method for transmitting the intermediate pilot according to the present invention is illustrated in the figure, in which the intermediate pilot is transmitted in the seventh symbol, and the intermediate pilots of the neighboring cells are in different positions in the same symbol.
Fig. 7(a) shows the transmission positions of the middle pilots in the sub-frame structure of 2 antennas of the base station 1, the middle pilots are inserted into the seventh symbol, and the interval between the adjacent pilots of each antenna is 8 sub-carriers, in the figure, P1 is the middle pilot of antenna 1, and P2 is the middle pilot of antenna 2. Fig. 7(b) and 7(c) are transmission positions of the intermediate pilots of the neighboring base stations 2 and 3, respectively, which are similar to fig. 7(a), and the same intermediate pilots of the base stations 2 and 3 are spaced from the base station 1 by 2 and 4 subcarriers, respectively. Thus, the pilot frequency is inserted into different sub-carrier positions of the same symbol by three adjacent cells, and the pilot frequency is orthogonal on the frequency, so that the condition of the channel can be measured by using smaller overhead, and the interference between the adjacent cells is avoided.
Example 9
This example is used to illustrate the case when the base station has 8 transmit antennas and places the intermediate pilots on the 3 rd and 4 th symbols of the sub-frame.
Fig. 8(a) shows the transmission position of the middle pilot within the basic resource block having a downlink sub-frame with 6 symbols when the base station uses 8 antennas, and the middle pilot occupies the carrier positions of the 3 rd and 4 th symbols within the basic resource block having a downlink sub-frame with 7 symbols as the positions described below.
Wherein P1 is the middle pilot of antenna 1, P2 is the middle pilot of antenna 2, P3 is the middle pilot of antenna 3, P4 is the middle pilot of antenna 4, P5 is the middle pilot of antenna 5, P6 is the middle pilot of antenna 6, P7 is the middle pilot of antenna 7, P8 is the middle pilot of antenna 8, each antenna has 3 pilots inside each basic resource block, and each antenna has 4 carriers adjacent pilot spacing; fig. 8(b) shows another mapping scheme between antenna pilots and symbols and carriers.
Example 10
This example is used to illustrate the case when the base station has 8 transmit antennas and places the intermediate pilots on the 3 rd and 4 th symbols of a subframe with 6 time domain symbols.
Fig. 9(a) shows an insertion method of the intermediate pilots at different densities inside the basic resource block having a downlink sub-frame of 6 symbols when the base station uses 8 antennas, and the intermediate pilots occupy the same carrier positions of the 3 rd and 4 th symbols as those described below for the inside of the basic resource block having a downlink sub-frame of 7 symbols.
Wherein P1 is the middle pilot of antenna 1, P2 is the middle pilot of antenna 2, P3 is the middle pilot of antenna 3, P4 is the middle pilot of antenna 4, P5 is the middle pilot of antenna 5, P6 is the middle pilot of antenna 6, P7 is the middle pilot of antenna 7, P8 is the middle pilot of antenna 8, for less overhead, each antenna has 2 pilots inside each basic resource block, and the adjacent pilots of each antenna are spaced by 8 carriers; fig. 9(b) shows another mapping scheme between antenna pilots and symbols and carriers.
Fig. 8 is different from fig. 9 in that each antenna in fig. 8 has 3 pilots inside each basic resource block, and the adjacent pilot interval of each antenna is 4 carriers; in fig. 9, each antenna has 2 pilots in each basic resource block, and the adjacent pilot interval of each antenna is 8 carriers, which means that the position shown in fig. 9 is used to transmit the intermediate pilot, and compared with the position shown in fig. 8 to transmit the intermediate pilot, system resources can be further saved.
Example 11
This example is used to illustrate the case when the base station has 8 transmit antennas and places the intermediate pilots on the 3 rd and 7 th symbols of a subframe with 7 time domain symbols.
Fig. 10(a) shows the transmission position of the middle pilot within the basic resource block of the 7-symbol downlink sub-frame when the base station uses 8 antennas, where P1 is the middle pilot of antenna 1, P2 is the middle pilot of antenna 2, P3 is the middle pilot of antenna 3, P4 is the middle pilot of antenna 4, P5 is the middle pilot of antenna 5, P6 is the middle pilot of antenna 6, P7 is the middle pilot of antenna 7, and P8 is the middle pilot of antenna 8, each antenna has 3 pilots within each basic resource block, and each antenna adjacent pilot is spaced by 4 carriers; fig. 10(b) shows another mapping scheme between antenna pilots and symbols and carriers.
Example 12
This example is used to illustrate the case when the base station has 8 transmit antennas and places the intermediate pilots on the 4 th and 7 th symbols of a subframe with 7 time domain symbols.
Fig. 11(a) shows the transmission position of the middle pilot within the basic resource block of the 7-symbol downlink sub-frame when the base station uses 8 antennas, where P1 is the middle pilot of antenna 1, P2 is the middle pilot of antenna 2, P3 is the middle pilot of antenna 3, P4 is the middle pilot of antenna 4, P5 is the middle pilot of antenna 5, P6 is the middle pilot of antenna 6, P7 is the middle pilot of antenna 7, and P8 is the middle pilot of antenna 8, each antenna has 3 pilots within each basic resource block, and each antenna adjacent pilot is spaced by 4 carriers; fig. 11(b) shows another mapping scheme between antenna pilots and symbols and carriers.
Example 13
This embodiment illustrates that the neighboring cells avoid the inter-interference of the intermediate pilots of the neighboring cells by transmitting the intermediate pilots at the same positions of different downlink subframes.
In this example, the base station negotiates to determine, at the time of access by all users: the base station sends the downlink intermediate pilot frequency every T frames, wherein the configuration among the adjacent 3 base stations is as follows:
the base station 1 places the middle pilot on the j (j is less than or equal to the number of subframes contained in the downlink frame) of the downlink frame with the index of i + Z × T (Z is an integer greater than 0), the base station 2 places the middle pilot on the j subframe of the downlink frame with the index of i + Z × T +1, and the base station 3 places the middle pilot on the j subframes of the downlink frame with the index of i + Z × T + 2.
Example 14
This example illustrates that each base station determines, according to the status of the downlink user, a subframe index for transmitting the intermediate pilot, and when the number of transmit antennas of the base station is 2, 4, and 8, the intermediate pilot is inserted in each basic resource block of the corresponding subframe by using a default pilot insertion manner, and then the user is notified by a broadcast message related to the intermediate pilot, for example, the broadcast message of the downlink frame has two indication fields: midamble _ Enable, Midamble _ Position _ Index, _ when Midamble _ Enable is 0, it means that the frame does not send the middle pilot, and the user no longer detects the Position information of the middle pilot; when Midamble _ Enable is 1, the frame has an intermediate pilot to transmit, and the Index number of the subframe in the frame where the intermediate pilot is transmitted can be indicated by Midamble _ Position _ Index. After detecting the message, the user detects the intermediate pilot at the corresponding position.
Example 15
This example illustrates that each base station informs the user whether to send the intermediate pilot in the current frame through a broadcast control message or a unicast control message related to the intermediate pilot in the downlink frame, and if the intermediate pilot is sent, the intermediate pilot is sent on the last subframe. For example, in the broadcast message of the downlink frame, an indication field is provided: and a Midamble _ Enable, wherein if the Midamble _ Enable is equal to 0, no transmission is performed, and if the Midamble _ Enable is equal to 1, an intermediate pilot is transmitted on the last downlink subframe. When the number of transmission antennas of the base station is 2, 4, and 8, the default pilot insertion method of fig. 3(a), 3(b), and 7(a) is used to insert the intermediate pilot in each basic resource block of the subframe.
Example 16
This example illustrates a case where the base station transmits the intermediate pilot on a predetermined downlink subframe, where the predetermined downlink subframe is a subframe other than the first subframe. For example, the index of the downlink subframe of the intermediate pilot in the downlink frame is predetermined as the second subframe. In each frame, the base station carries an indication field in the message sent by the broadcast control channel or the unicast control channel of the downlink frame: and a Midamble _ Enable, wherein if the Midamble _ Enable is equal to 0, no transmission is performed, and if the Midamble _ Enable is equal to 1, an intermediate pilot is transmitted on the second downlink subframe. And when the number of the transmitting antennas of the base station is 2, 4 and 8, respectively adopting a default pilot frequency insertion mode to insert the middle pilot frequency in the basic resource block of the corresponding subframe.
Example 17
This example illustrates that the base station informs the user of the position of the intermediate pilot by broadcasting a control message or unicasting a control downlink: the base station determines whether the current frame transmits the intermediate pilot by transmitting a broadcast control message or a unicast control message: and the base station sends a broadcast control message or a unicast control message in the ith frame to inform the user that the user will send downlink intermediate pilot frequency in a period of T4 frames from the ith frame to the i +102 frame, and the base station sends the broadcast message in the corresponding frame to inform the user of the sub-frame index to which the intermediate pilot frequency belongs in the current frame, and when the number of sending antennas of the base station is 2, 4 and 8, the intermediate pilot frequency is respectively inserted in the basic resource block of the corresponding sub-frame in a default pilot frequency insertion mode, so that the terminal detects the corresponding intermediate pilot frequency in the corresponding sub-frame.
Example 18
This example illustrates a case where the base station transmits the intermediate pilot on a predetermined subframe of a predetermined frame in a downlink superframe, where the predetermined downlink subframe is a subframe other than the first subframe. For example, it is predefined that the intermediate pilot is transmitted in the second sub-frame of the first downlink frame in the super-frame. Then in each superframe, the base station carries an indication field in the message sent by the broadcast control channel or the unicast control channel of the downlink superframe: and a Midamble _ Enable, which does not transmit if Midamble _ Enable is equal to 0, and transmits an intermediate pilot on a second subframe of a first downlink frame of a first superframe if Midamble _ Enable is equal to 1. And when the number of the transmitting antennas of the base station is 2, 4 and 8, respectively adopting a default pilot frequency insertion mode to insert the middle pilot frequency in the basic resource block of the corresponding subframe.
It should be noted that the above mentioned embodiments are only preferred embodiments of the present invention, and the technical solution of the present invention is not further limited, and the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived 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.
Claims (20)
1. A method for transmitting downlink intermediate pilot in a wireless communication system, comprising:
the base station sends the middle pilot frequency on one or two symbols in the third, fourth or seventh symbols in the downlink subframe;
the method further comprises the following steps:
adjacent cells select the same sub-frame of different frames or different sub-frames of the same frame or send middle pilot frequency on different symbols of the same sub-frame; or,
the adjacent cells send middle pilot frequency on the same symbol of the same subframe, and adopt different code sequences as pilot signals; or,
and the adjacent cells send the intermediate pilot frequency on the same symbol of the same subframe, and when the number of the base station sending antennas is 2, the adjacent cells send the intermediate pilot frequency in a frequency division multiplexing mode.
2. The method of claim 1,
when the number of transmit antennas of the base station is 2 or 4, the base station transmits the intermediate pilot on the third or fourth or seventh symbol in the downlink subframe.
3. The method of claim 1,
when the number of the transmitting antennas of the base station is 8, the base station transmits a pilot on the third and fourth symbols or the third and seventh symbols or the fourth and seventh symbols in the downlink subframe.
4. The method of claim 1, wherein the method further comprises: and the base station sends the intermediate pilot frequency on the frequency domain subcarriers of one or two symbols of the downlink subframe.
5. The method of claim 4, wherein the base station transmits the intermediate pilot on frequency domain subcarriers of one or two symbols of a downlink subframe, comprising:
when the number of the transmitting antennas is 2 or 4, the relative position index Set of the middle pilot Carrier corresponding to the (n + 1) th antenna (n is more than or equal to 0 and less than or equal to 3) in the basic resource block is Midamble _ Carrier _ Set _ PRU:
Midamble_Carrier_Set_PRU＝3+n+k1Δs；
wherein k is1＝0,1,2,…K1-1, index of intermediate pilot on basic resource block; k1Representing the number of intermediate pilots inserted in one resource block by each antenna; Δ s is the inner part of each basic resource block for each antennaThe number of carrier spacings between two adjacent pilots.
6. The method of claim 5, wherein the base station transmits the intermediate pilot on frequency domain subcarriers of one or two symbols of a downlink subframe, further comprising:
when the intermediate pilot is inserted over the full bandwidth, the occupied physical Carrier position index Midamble _ Carrier _ Set is:
when the middle pilot frequency is inserted in the partial resource block on the full bandwidth, the occupied physical Carrier position index Midamble _ Carrier _ Set is:
wherein k is2＝0,1,2,…K2-1, index of the intermediate pilot over full bandwidth; k2Representing the number of intermediate pilots inserted on the system bandwidth by each antenna; Δ s is the carrier spacing number between two adjacent pilot frequencies in the basic resource block of each antenna; m is the number of the middle pilot frequencies of each antenna in each basic resource block;is expressed as being equal to or less thanMod (k) is the maximum integer of2M) represents k2The remainder of the whole division by m; n is a radical ofusedRepresenting the number of all the remaining sub-carriers after the system removes the two side guard interval sub-carriers, SiAnd the physical position index corresponding to the first subcarrier of the ith resource block in which the intermediate pilot is inserted is shown, and i belongs to {0,1,2, … M } which is a basic resource block index set in which the intermediate pilot needs to be inserted.
7. The method of claim 4, wherein the base station transmits an intermediate pilot on frequency domain subcarriers of two symbols of a downlink subframe, comprising:
when the number of the transmitting antennas of the base station is 8, the relative position index Set of the middle pilot Carrier corresponding to the (n + 1) th antenna (n is more than or equal to 0 and less than or equal to 7) in each basic resource block is Midamble _ Carrier _ Set _ PRU:
or the following steps:
Midamble_Carrier_Set_PRU＝3+mod(n,4)+k1Δs；
wherein k is1＝0,1,2,…K1-1, index of intermediate pilot on basic resource block; k1Representing the number of intermediate pilots inserted in one resource block by each antenna; Δ s is the number of carrier intervals between two adjacent pilot frequencies in each basic resource block of each antenna;
wherein the middle pilot frequency of 4 antennas is on the sub-carrier corresponding to one symbol of the two symbols, and the middle pilot frequency of the other 4 antennas is on the sub-carrier corresponding to the other symbol of the two symbols.
8. The method of claim 7, wherein the base station transmits an intermediate pilot on frequency domain subcarriers of two symbols of a downlink subframe, further comprising:
when the intermediate pilot is inserted over the full bandwidth, the occupied physical Carrier position index Midamble _ Carrier _ Set is:
or the following steps:
and the number of the first and second groups,
when the middle pilot frequency is inserted in partial resource block on the full bandwidth, the index of occupying physical Carrier position, Midamble _ Carrier _ Set, is
Wherein k is1＝0,1,2,…K1-1, index of intermediate pilot on basic resource block; k1Representing the number of intermediate pilots inserted in one resource block by each antenna; k is a radical of2＝0,1,2,…K2-1, index over full bandwidth for the intermediate pilot for each antenna; k2Representing the number of intermediate pilots inserted on the system bandwidth by each antenna; m is the number of the middle pilot frequencies of each antenna in each basic resource block; Δ s is the number of carrier intervals between two adjacent pilot frequencies of each antenna;is expressed as being equal to or less thanThe smallest integer of (a); n is a radical ofusedRepresenting the number of all the remaining subcarriers after the system removes the subcarriers of the guard interval at two sides; siThe physical position index corresponding to the first subcarrier of the ith resource block inserted with the intermediate pilot is represented, and i belongs to {0,1,2, … M } which is a basic resource block index set needing to be inserted with the intermediate pilot;
wherein the middle pilot frequency of 4 antennas is on the sub-carrier corresponding to one symbol of the two symbols, and the middle pilot frequency of the other 4 antennas is on the sub-carrier corresponding to the other symbol of the two symbols.
9. The method of claim 1, wherein the frequency division multiplexing refers to adjacent cells selecting different Carrier sets within a basic resource block and on the same symbol frequency domain to transmit the middle pilot, and a pilot Carrier Set Midamble _ Carrier _ Set _ PRU and a full-bandwidth middle pilot Carrier physical position index Set Midamble _ Carrier _ Set used within each basic resource block of adjacent three cells are respectively:
cell 1:
Midamble_Carrier_Set_PRU＝3+n+k1Δs；
cell 2 uses a carrier set:
Midamble_Carrier_Set_PRU＝3+n+k1Δs+ΔBS；
cell 3 uses a carrier set:
Midamble_Carrier_Set_PRU＝3+n+k1Δs+2ΔBS；
wherein k is1＝0,1,2,…K1-1, index of intermediate pilot on basic resource block; k1Representing the number of intermediate pilots inserted in one resource block by each antenna; k is a radical of2＝0,1,2,…K2-1, index over full bandwidth for the intermediate pilot for each antenna; k2Representing the number of intermediate pilots inserted on the system bandwidth by each antenna; m is the number of the middle pilot frequencies of each antenna in each basic resource block; Δ s is the number of carrier intervals between two adjacent pilot frequencies of each antenna;is expressed as being equal to or less thanThe smallest integer of (a); n is a radical ofusedRepresenting the number of all the remaining subcarriers after the system removes the subcarriers of the guard interval at two sides; siResource block representing ith inserted intermediate pilotI belongs to {0,1,2, … M } is a basic resource block index set which needs to insert the middle pilot; wherein ΔBSThe number of carrier intervals of the middle pilot frequency in the frequency domain in each basic resource block of the adjacent cell.
10. A method for transmitting downlink intermediate pilot in a wireless communication system, comprising:
the base station sends a message to inform the user terminal of the position of the middle pilot frequency in the downlink frame through a broadcast control channel and/or a unicast control channel;
the method further comprises the following steps:
adjacent cells select the same sub-frame of different frames or different sub-frames of the same frame or send middle pilot frequency on different symbols of the same sub-frame; or
The adjacent cells send middle pilot frequency on the same symbol of the same subframe, and adopt different code sequences as pilot signals; or
And the adjacent cells send the intermediate pilot frequency on the same symbol of the same subframe, and when the number of the base station sending antennas is 2, the adjacent cells send the intermediate pilot frequency in a frequency division multiplexing mode.
11. The method of claim 10, wherein the message comprises:
whether the current frame or the super frame has the intermediate pilot frequency and/or the frame and/or subframe index to which the intermediate pilot frequency symbol belongs; or,
the base station transmits the intermediate pilot frequency in a period T frame at a continuous S frame which is shifted backwards by delta S frame from a frame where the current message is positioned, and transmits a message informing a terminal of a sub-frame index to which an intermediate pilot frequency symbol belongs through a broadcast control channel and/or a unicast control channel at the frame which correspondingly transmits the intermediate pilot frequency;
where Δ S, S, T is a natural number.
12. The method of claim 10, wherein the message sent over the unicast control channel is a non-user-specific control message of a downlink frame.
13. The method of claim 10, wherein the method further comprises:
when the number of antennas is 2 or 4:
the base station sends the middle pilot frequency in the third, fourth or seventh symbol in the downlink subframe;
and determining a middle pilot Carrier relative position index Set Midamble _ Carrier _ Set _ PRU corresponding to the (n + 1) th antenna (n is more than or equal to 0 and less than or equal to 3) in the basic resource block as follows:
Midamble_Carrier_Set_PRU＝3+n+k1Δ s; and the number of the first and second groups,
when the intermediate pilot is inserted over the full bandwidth, the occupied physical Carrier position index Midamble _ Carrier _ Set is:
and the number of the first and second groups,
when the middle pilot frequency is inserted in the partial resource block on the full bandwidth, the occupied physical Carrier position index Midamble _ Carrier _ Set is:
when the number of antennas is 8:
the base station sends middle pilot frequency in the third and fourth symbols in the downlink sub-frame;
and determining that the corresponding middle pilot Carrier relative position index Set Midamble _ Carrier _ Set _ PRU and the middle pilot Carrier physical position index Set Midamble _ Carrier _ Set of the full bandwidth of the (n + 1) th antenna (n is more than or equal to 0 and less than or equal to 7) in the basic resource block are respectively:
or
Midamble_Carrier_Set_PRU＝3+mod(n,4)+k1Δ s; and the number of the first and second groups,
occupying physical carrier position index when intermediate pilot is inserted over full bandwidth
Midamble _ Carrier _ Set is:
or;
and the number of the first and second groups,
when the middle pilot frequency is inserted in partial resource block on the full bandwidth, the index of occupying physical Carrier position, Midamble _ Carrier _ Set, is
Wherein k is1＝0,1,2,…K1-1, index of intermediate pilot on basic resource block; k1Representing the number of intermediate pilots inserted in one resource block by each antenna; k is a radical of2＝0,1,2,…K2-1, index over full bandwidth for the intermediate pilot for each antenna; k2Representing the number of intermediate pilots inserted on the system bandwidth by each antenna; m is the number of the middle pilot frequencies of each antenna in each basic resource block; Δ s is the number of carrier intervals between two adjacent pilot frequencies of each antenna;is expressed as being equal to or less thanThe smallest integer of (a); n is a radical ofusedRepresenting the number of all the remaining subcarriers after the system removes the subcarriers of the guard interval at two sides; siAnd the physical position index corresponding to the first subcarrier of the ith resource block in which the intermediate pilot is inserted is shown, and i belongs to {0,1,2, … M } which is a basic resource block index set in which the intermediate pilot needs to be inserted.
14. The method of claim 13, wherein the frequency division multiplexing refers to selecting different Carrier sets in the same symbol frequency domain within a basic resource block to transmit the middle pilot by neighboring cells, and a pilot Carrier Set midamblecarrier Set PRU and a full-bandwidth middle pilot Carrier physical position index Set midamblecarrier Set are used in each basic resource block of neighboring three cells, respectively:
cell 1:
Midamble_Carrier_Set_PRU＝3+n+k1Δs；
cell 2 uses a carrier set:
Midamble_Carrier_Set_PRU＝3+n+k1Δs+ΔBS；
cell 3 uses a carrier set:
Midamble_Carrier_Set_PRU＝3+n+k1Δs+2ΔBS；
wherein k is1＝0,1,2,…K1-1, index of intermediate pilot on basic resource block; k1Representing the number of intermediate pilots inserted in one resource block by each antenna; k is a radical of2＝0,1,2,…K2-1, index over full bandwidth for the intermediate pilot for each antenna; k2Representing the number of intermediate pilots inserted on the system bandwidth by each antenna; m is the number of the middle pilot frequencies of each antenna in each basic resource block; Δ s is the number of carrier intervals between two adjacent pilot frequencies of each antenna;is expressed as being equal to or less thanThe smallest integer of (a); n is a radical ofusedRepresenting the number of all the remaining subcarriers after the system removes the subcarriers of the guard interval at two sides; siThe physical position index corresponding to the first subcarrier of the ith resource block inserted with the intermediate pilot is represented, and i belongs to {0,1,2, … M } which is a basic resource block index set needing to be inserted with the intermediate pilot; wherein ΔBSThe carrier spacing in the frequency domain of the middle pilot within each basic resource block for the adjacent cell.
15. A method for transmitting downlink intermediate pilot in a wireless communication system, comprising:
the base station sends the intermediate pilot frequency in one subframe except the first subframe or a plurality of subframes except the first subframe in a downlink frame;
or the base station sends the intermediate pilot frequency in one subframe except the first subframe or a plurality of subframes except the first subframe of one downlink frame of the downlink superframe;
the method further comprises the following steps:
adjacent cells select the same sub-frame of different frames or different sub-frames of the same frame or send middle pilot frequency on different symbols of the same sub-frame; or,
the adjacent cells send middle pilot frequency on the same symbol of the same subframe, and adopt different code sequences as pilot signals; or,
and the adjacent cells send the intermediate pilot frequency on the same symbol of the same subframe, and when the number of the base station sending antennas is 2, the adjacent cells send the intermediate pilot frequency in a frequency division multiplexing mode.
16. The method of claim 15, wherein the base station transmits the intermediate pilot in a last downlink subframe of a downlink frame, or the base station transmits the intermediate pilot in a last subframe of a downlink frame of a downlink superframe.
17. The method of claim 15, wherein the method further comprises:
when the terminal is accessed, the base station informs the terminal of the position of the downlink subframe of the intermediate pilot frequency sent by the base station through the access control related message.
18. The method of claim 15, wherein the method further comprises:
the base station sends a message through a broadcast control channel and/or a unicast control channel to inform the terminal whether the current super frame and/or frame sends the intermediate pilot frequency, and if the current super frame and/or frame sends the intermediate pilot frequency, the base station sends the intermediate pilot frequency on the determined downlink frame and/or sub frame.
19. The method of claim 15, wherein the method further comprises:
when the number of antennas is 2 or 4:
the base station sends the middle pilot frequency in the third, fourth or seventh symbol in the downlink subframe;
and determines the corresponding middle pilot carrier of the (n + 1) th antenna (n is more than or equal to 0 and less than or equal to 3) in the basic resource block
The relative position index Set Midamble _ Carrier _ Set _ PRU is:
Midamble_Carrier_Set_PRU＝3+n+k1Δ s; and
when the intermediate pilot is inserted over the full bandwidth, the occupied physical Carrier position index Midamble _ Carrier _ Set is:
and
when the middle pilot frequency is inserted in the partial resource block on the full bandwidth, the occupied physical Carrier position index Midamble _ Carrier _ Set is:
when the number of antennas is 8:
the base station sends middle pilot frequency in the third and fourth symbols in the downlink sub-frame;
and determining that the corresponding middle pilot Carrier relative position index Set Midamble _ Carrier _ Set _ PRU and the middle pilot Carrier physical position index Set Midamble _ Carrier _ Set of the full bandwidth of the (n + 1) th antenna (n is more than or equal to 0 and less than or equal to 7) in the basic resource block are respectively:
or
Midamble_Carrier_Set_PRU＝3+mod(n,4)+k1Δ s; and
occupying physical carrier position index when intermediate pilot is inserted over full bandwidth
Midamble _ Carrier _ Set is:
or
And the number of the first and second groups,
when the middle pilot frequency is inserted in partial resource block on the full bandwidth, the index of occupying physical Carrier position, Midamble _ Carrier _ Set, is
Wherein k is1＝0,1,2,…K1-1, index of intermediate pilot on basic resource block; k1Representing the number of intermediate pilots inserted in one resource block by each antenna; k is a radical of2＝0,1,2,…K2-1, index over full bandwidth for the intermediate pilot for each antenna; k2Representing the number of intermediate pilots inserted on the system bandwidth by each antenna; m being per antenna within each basic resource blockThe number of intermediate pilot frequencies; Δ s is the number of carrier intervals between two adjacent pilot frequencies of each antenna;is expressed as being equal to or less thanThe smallest integer of (a); n is a radical ofusedRepresenting the number of all the remaining subcarriers after the system removes the subcarriers of the guard interval at two sides; siAnd the physical position index corresponding to the first subcarrier of the ith resource block in which the intermediate pilot is inserted is shown, and i belongs to {0,1,2, … M } which is a basic resource block index set in which the intermediate pilot needs to be inserted.
20. The method of claim 19, wherein the frequency division multiplexing refers to selecting different Carrier sets in the same symbol frequency domain within a basic resource block to transmit the middle pilot by neighboring cells, and a pilot Carrier Set midamblecarrier Set PRU and a full-bandwidth middle pilot Carrier physical position index Set midamblecarrier Set are used in each basic resource block of neighboring three cells, respectively:
cell 1:
Midamble_Carrier_Set_PRU＝3+n+k1Δs；
cell 2 uses a carrier set:
Midamble_Carrier_Set_PRU＝3+n+k1Δs+ΔBS；
cell 3 uses a carrier set:
Midamble_Carrier_Set_PRU＝3+n+k1Δs+2ΔBS；
wherein k is1＝0,1,2,…K1-1, index of intermediate pilot on basic resource block; k1Representing the number of intermediate pilots inserted in one resource block by each antenna; k is a radical of2＝0,1,2,…K2-1, index over full bandwidth for the intermediate pilot for each antenna; k2Representing the number of intermediate pilots inserted on the system bandwidth by each antenna; m is the number of the middle pilot frequencies of each antenna in each basic resource block; Δ s is the number of carrier intervals between two adjacent pilot frequencies of each antenna;is expressed as being equal to or less thanThe smallest integer of (a); n is a radical ofusedRepresenting the number of all the remaining subcarriers after the system removes the subcarriers of the guard interval at two sides; siThe physical position index corresponding to the first subcarrier of the ith resource block inserted with the intermediate pilot is represented, and i belongs to {0,1,2, … M } which is a basic resource block index set needing to be inserted with the intermediate pilot; wherein ΔBSThe carrier spacing in the frequency domain of the middle pilot within each basic resource block for the adjacent cell.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910134724.4A CN101867948B (en) | 2009-04-14 | 2009-04-14 | Method for sending downlink intermediate pilot in wireless communication system |
| PCT/CN2009/075881 WO2010118617A1 (en) | 2009-04-14 | 2009-12-23 | Method for sending downlink midambles in a wireless communication system |
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| Application Number | Priority Date | Filing Date | Title |
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| CN200910134724.4A CN101867948B (en) | 2009-04-14 | 2009-04-14 | Method for sending downlink intermediate pilot in wireless communication system |
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| CN102394675B (en) * | 2011-06-29 | 2017-02-08 | 中兴通讯股份有限公司 | Base station and methods for selecting service mode and feeding back pre-coding matrix |
| JP2017508318A (en) * | 2013-12-16 | 2017-03-23 | 華為技術有限公司Ｈｕａｗｅｉ Ｔｅｃｈｎｏｌｏｇｉｅｓ Ｃｏ．，Ｌｔｄ． | Method for transmitting pilot signal, base station, and user equipment |
| CN105847208B (en) * | 2015-01-13 | 2019-04-30 | 上海数字电视国家工程研究中心有限公司 | The method for selecting and design method of CP continuous pilot number based on OFDM technology |
| US10505772B2 (en) * | 2016-10-26 | 2019-12-10 | Qualcomm Incorporated | Non-staggered reference signals and repeated pilots in orthogonal frequency-division multiplexing |
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| US6954481B1 (en) * | 2000-04-18 | 2005-10-11 | Flarion Technologies, Inc. | Pilot use in orthogonal frequency division multiplexing based spread spectrum multiple access systems |
| CN1146170C (en) * | 2000-11-27 | 2004-04-14 | 华为技术有限公司 | Improved method for joint test spectrum-spread multi-user communicaltion system |
| CN100426704C (en) * | 2002-06-06 | 2008-10-15 | 华为技术有限公司 | Method for ralizing synchronization in TDD radio communication system |
| KR100594597B1 (en) * | 2003-10-24 | 2006-06-30 | 한국전자통신연구원 | Method and apparatus for embodying downlink signal in mobile communication system, and method and apparatus for synchronizing and searching cell using the same |
| CN101047675A (en) * | 2006-06-14 | 2007-10-03 | 华为技术有限公司 | Implementing method and device of pre-pilot frame |
| CN101237439B (en) * | 2008-02-28 | 2010-08-18 | 北京北方烽火科技有限公司 | A sub-carrier intercrossed discrete pilot interposition method in OFDM system |
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