FIG. 1 shows a system structure diagram according to the related technologies. The Long Term Evolution Advanced (LTE-A) system adds new links after introducing Relay Nodes (RNs), and the corresponding terminologies include that: a link between an eNode-B (eNB), which is also known as Node B or base station, and the RN is named as a backhaul link, a link between the RN and User Equipment (UE) is named as an access link, and a link between the eNB and the UE is named as a direct link. An inband-relay refers to the links, which are from the eNB to a relay and is from the relay to the UE are operated on the same frequency resource. As an inband-relay transmitter may cause interference to the own receiver (self-interference), it is impossible for the link from the eNB to the relay and the link from the relay to the UE to be synchronously on the same frequency resource, only if there is enough signal separation and antenna isolation. Similarly, the relay cannot transmit data to the eNB while receiving the data transmitted from the UE. A possible method of solving the receiving and transmitting interference is that the relay does not implement transmission operation for the UE while receiving the data from the eNB, namely, a “gap” needs to be added after being relayed to the link of UE, thus being used for a backhaul subframe by configuring a Multicast Broadcast Single Frequency Network (MBSFN) subframe, so that the UE does not implement any receiving/transmitting operation within the time range of “gap”, but, the relay completes the switching from transmitting to receiving within the time range of “gap”, a subsequent Orthogonal Frequency Division Multiplexing (OFDM) symbol receives the data from the eNB after completing the switching. In the related art, a specific way of adopting the MBSFN subframe to be used for the backhaul subframe in the Long Term Evolution (LTE) system is that a Multimedia Broadcast Multicast Service (MBMS) Control Entity (MCE) firstly configures one or more available MBSFN subframes for the eNB, and then the eNB configures the available backhaul subframe in the available MBSFN subframes.
FIG. 2 shows a diagram of a frame structure in the related technologies; according to the requirements in the current LTE system, a 10 ms radio frame consists of 10 1 ms subframes, and may include Unicast and Multicast. In the above, when adopting a Frequency Division Duplex (FDD) mode, the #0 and #5 subframes are used for transmitting synchronization signals, and the #4 and #9 subframes are used for paging; when adopting a Time Division Duplex (TDD) mode, the #0 and #5 subframes are used for transmitting the synchronization signals, and the #1 and #6 subframes are used for paging, namely, as the FDD (#0, #4, #5, #9) subframes and is the TDD (#0, #1, #5, #6) subframes have the above special purposes, they cannot be used for distributing the MBSFN subframes, namely, the MBSFN subframes capable of being distributed in one radio frame are at most 6 subframes.
In the LTE system, the transmission of the data between the UE and the eNB needs to establish a Hybrid Automatic Repeat Request (HARQ) progress and implement corresponding feedback. When the UE receives the data of the eNB, the UE generates Uplink (UL) feedback information (for example, UL ACK/Negative ACK (NACK)) according to the decoding condition, and transmits the information to the eNB. And then, the eNB implements the next treatment according to the received information, if receiving that the ACK is equal to 1 or 0 (respectively representing that the ACK is valid when it is “1” or “0”), new data can be transmitted; if receiving that the NACK is equal to 0 or 1 (respectively representing that the NACK is valid when it is “0” or “1”), the data which needs to be retransmitted is retransmitted to the UE.
As the backhaul link cannot use the FDD (#0, #4, #5, #9) Downlink (DL) subframes, it correspondingly cannot use the FDD (#4, #8, #9, #3) UL subframes. The current design for the UL HARQ mainly includes the combination of DL subframes and UL subframes only using the multiples of 8 ms or 16 ms, namely, supposing that within the 40 ms range, the 8 sets of the DL subframes include {(#7 #23 #31), (#6 #22 #38), (#13 #21 #37), (#12 #28 #36 ), (#3 #11 #27), (#2 #18 #26), (#1 #17 #33), (#8 #16 #32)}, the corresponding 8 sets of the UL subframes include {(#11 #27 #35), (#10 #26 #42), (#7 #25 #41), (#16 #32 #40), (#7 #15 #31), (#6 #22 #30), (#5 #21 #37), (#12 #20 #36)}, wherein, the subframes greater than “40” can implement modulo calculation for “40” during the calculation process, such as mod (42, 40)=2. Actually, one DL subframe set is corresponding to one UL subframe set, namely, from the overall UL and DL subframe sets, there are 8 DL and UL subframe sets, conditions of combining different sets totally includes 2 to the 8th power of sets (namely, 256 sets). As the DL subframe may have the corresponding UL subframe with 4 ms interval, the feedback of the UL ACK/NACK needs no modification as the LTE, however, when initially switching the subframe configuration, the relation is between the corresponding UL subframe and the DL subframe when switching the subframe configuration may not satisfy the relation of 4 ms any more.
Specifically, the set index is as shown in Table 1, it should be noted that the relation between the set and the set index is not limited to the corresponding relation in Table 1. The 8 bits bitmap mode only exists when distributing the subframes, namely, the binary of 8 bits respectively corresponds to different set indexes, the receiving end can obtain the subframe configuration once obtaining the set index.
TABLE 1Set indexDL setUL set0(#7 #23 #31)(#11 #27 #35)1(#6 #22 #38)(#10 #26 #42)2(#13 #21 #37)(#17 #25 #41)3(#12 #28 #36)(#16 #32 #40)4(#3 #11 #27)(#7 #15 #31)5(#2 #18 #26)(#6 #22 #30)6(#1 #17 #33)(#5 #21 #37)7(#8 #16 #32)(#12 #20 #36)
Specifically, the number of HARQ progresses corresponding to the conditions of 256 sets are as shown in Table 2, in which the combination configuration in the first array is decimal, for example, the binary of “170” represented as 8 bits is “10101010”, which represents that the sets corresponding to the set indexes which are “7”, “5”, “3”, “1” are combined together.
TABLE 2CombinationNumber ofCombination configurationnumberHARQNumber ofNumber of(decimal)(256)progressessetssubframes010001, 2, 4, 8, 16, 32, 64, 12881133, 5, 6, 9, 10, 12, 17, 18, 20, 24,2822633, 34, 36, 40, 48, 65, 66, 68,72, 80, 96, 129, 130, 132, 136,144, 160, 1927, 11, 13, 14, 19, 21, 22, 25, 26,5833, 49, 1228, 35, 37, 38, 41, 42, 44, 49,50, 52, 56, 67, 69, 70, 73, 74,76, 81, 82, 84, 85, 88, 97, 98,100, 104, 112, 131, 134, 137,138, 140, 145, 146, 148, 152,161, 162, 164, 168, 170, 176,193, 194, 196, 200, 208, 22415, 23, 27, 29, 30, 39, 43, 45,8444, 512, 1546, 51, 53, 54, 57, 58, 60, 71,75, 77, 78, 83, 86, 87, 89, 90,91, 92, 93, 99, 101, 102, 105,106, 107, 108, 109, 113, 114,116, 117, 120, 135, 139, 141,142, 147, 149, 150, 153, 154,156, 163, 165, 166, 169, 171,172, 173, 174, 177, 178, 180,181, 182, 184, 186, 195, 197,198, 201, 202, 204, 209, 210,212, 213, 214, 216, 218, 225,226, 228, 232, 234, 24031, 47, 55, 59, 61, 62, 79, 94,6055, 615, 1895, 103, 110, 111, 115, 118, 119,121, 122, 123, 124, 125, 143,151, 155, 157, 158, 167, 175,179, 183, 185, 187, 188, 189,190, 199, 203, 205, 206, 211,215, 217, 219, 220, 221, 222,227, 229, 230, 233, 235, 236,237, 238, 241, 242, 244, 245,246, 248, 25063, 126, 127, 159, 191, 207,1766, 7, 818, 21, 24223, 231, 239, 243, 247, 249,251, 252, 253, 254, 255
The inventor finds that a solution of how to feed back the ACK information during switching of backhaul link subframe configuration is not provided in the relevant art.