[0059] In order to express the objectives, technical solutions and advantages of the present invention more clearly, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0060] In this embodiment of the present invention, use N bundled The aggregation level and transmission power of the PDCCH are adjusted to improve the transmission performance and transmission efficiency of the PDCCH. Adjustment using known parameters does not require additional complexity of LTE device implementation, and has high accuracy.
[0061] According to the relevant protocol, the uplink control information (UCI) is transmitted on the PUSCH channel, and the ACK/NACK mode is set to bundling, and the base station can determine the N used by the UE according to the received signal. bundled parameter.
[0062] use N bundled It can reflect the loss of DCI. Since the base station itself does not know that the UE has received the DCI, it is necessary to use a blind detection method to determine the N used by the UE. bundled , and descramble the received ACK/NACK. by N bundled The base station can know the number of DCIs received by the UE, so as to determine the loss of DCI by the UE. According to the loss of DCI by the UE, the base station adjusts the aggregation level and transmit power of the PDCCH.
[0063] If the UE loses DCI, the aggregation level or transmission power of PDCCH can be increased to improve the transmission reliability of PDCCH; if the UE does not lose DCI, the aggregation level or transmission power of PDCCH can be decreased to avoid waste of resources.
[0064] attached figure 1 It is a schematic flowchart of the method for adjusting the physical downlink control channel, which specifically includes the following steps:
[0065] 101. Determine the minimum aggregation level τ of the PDCCH according to the DCI format of the UE min and the maximum aggregation level τ max.
[0066] 102. Determine the N used by the UE according to the received signal bundled parameter. The specific determination processes of 101 and 102 are all in the prior art, and the description is not repeated here.
[0067] 103. By N bundled and the number N of DCIs carried by the base station on the PDCCH DAI Calculate the state statistics of PDCCH △ PDCCH.
[0068] According to N bundled , the base station judges whether the UE has lost DCI and the number of lost DCIs, and then calculates △ according to the judgment PDCCH.
[0069] 1) Initialize △ PDCCH , △ PDCCH The initial value of is 0.
[0070] 2) When the UE's PUSCH transmission is scheduled based on the detected PDCCH DCI format 0/4,
[0071] when N bundled =N DAI , it means that the UE has not lost DCI, then △ PDCCH =△’ PDCCH -1, △' PDCCH is the last state statistic of PDCCH, △’ PDCCH The initial value of is 0;
[0072] when N bundled ≠N DAI , and N bundled =N DAI When +2, it means that the UE lost DCI, △ PDCCH =△’ PDCCH +1;
[0073] when N bundled ≠N DAI , and N bundled ≠N DAI When +2, it means that the uplink grant of the UE is lost, the UE is in the DTX state, △ PDCCH =△’ PDCCH +2.
[0074] 3) When the UE's PDSCH transmission is not based on the detected PDCCH DCI format 0 or 4 scheduling,
[0075] when N bundled =N DAI , it means that the UE has not lost DCI, △ PDCCH =△’ PDCCH -1;
[0076] when N bundled ≠N DAI time, △ PDCCH =△’ PDCCH +δ,δ=N bundled -N DAI. δ is the number of packets lost by the UE.
[0077] 104. According to △ PDCCH First adjust the aggregation level of PDCCH, when the current aggregation level τ is greater than the minimum aggregation level (τ min ) and the maximum aggregation level (τ max ), according to △ PDCCH Then adjust the PDCCH transmit power.
[0078] In the present invention, the PDCCH is adjusted by the aggregation level of the PDCCH and the transmission power of the PDCCH. First adjust the aggregation level of the PDCCH, and then adjust the transmit power of the PDCCH when it exceeds the adjustment range of the aggregation level. Doing so can effectively avoid wasting resources.
[0079] The preset setting adjusts the threshold A upward, where A is greater than zero, where the specific value of A is related to τ. For example, when τ is adjusted from 2 to 4, then A=A1; when τ is adjusted from 4 to 8, then A=A2, A1≠A2. Pre-set down adjustment threshold B, B is less than zero. The specific data of B is related to τ. For example, when τ is adjusted from 2 to 4, then B=B1; when τ is adjusted from 4 to 8, then B=B2, B1≠B2. Case 1
[0080] a1)△ PDCCH greater than A, then τ=τ'+1, where τ' is the previous aggregation level.
[0081] b1) When τ is greater than τ max When , the current aggregation level is adjusted again, and the adjusted aggregation level is equal to τ-1.
[0082] c1) PDCCH transmission power after adjustment = PDCCH transmission power before adjustment + transmission power adjustment step size. The transmission power adjustment step size is preset.
[0083] Case 2
[0084] a2)△ PDCCH is less than B, then τ=τ'-1.
[0085] b2) When τ is less than τ min When , the current aggregation level is adjusted again, and the adjusted aggregation level is equal to τ+1.
[0086] c2) PDCCH transmission power after adjustment = PDCCH transmission power before adjustment - transmission power adjustment step size.
[0087] see attached figure 2 It is an apparatus for adjusting the physical downlink control channel, which includes: a receiving module 201 , a calculating module 202 and an adjusting module 203 .
[0088] The main function of the receiving module 201 is to receive the user's DCI and receive signals. Determine the τ of the PDCCH according to the DCI format of the downlink control signal of the UE min and τ max , determine the N used by the UE according to the received signal bundled parameter.
[0089] The calculation module 202 is mainly composed of N bundled and the number N of DCIs carried by the base station on the PDCCH DAI Calculate the state statistics of PDCCH △ PDCCH.
[0090] The adjustment module 203 is used to adjust the aggregation level of the PDCCH and the transmission power of the PDCCH. Specifically, first adjust the aggregation level of PDCCH, and at the current aggregation level τ is greater than τ max or less than τ min , according to △ PDCCH Then adjust the PDCCH transmit power.
[0091] The calculation module 202 is further used for, when the PDSCH transmission of the UE is based on the scheduling that the format of the detected PDCCH DCI is 0 or 4,
[0092] when N bundled =N DAI time, △ PDCCH =△’ PDCCH -1;
[0093] when N bundled ≠N DAI , and N bundled =N DAI +2, △ PDCCH =△’ PDCCH +1;
[0094] when N bundled ≠N DAI , and N bundled ≠N DAI +2, △ PDCCH =△’ PDCCH +2.
[0095] When the PDSCH transmission of the UE is not based on the scheduling that the format of the detected PDCCH DCI is 0 or 4, the calculation module 202 is further configured to:
[0096] when N bundled =N DAI time, △ PDCCH =△’ PDCCH -1;
[0097] when N bundled ≠N DAI time, △ PDCCH =△’ PDCCH +δ,δ=N bundled -N DAI.
[0098] The adjustment module 203 adjusts the aggregation level of the PDCCH in the following manner:
[0099] Case 1:
[0100] △ PDCCH greater than A, then τ=τ’+1; when τ is greater than τ max , the adjusted aggregation level is equal to τ-1.
[0101] Case two:
[0102] △ PDCCH is less than B, then τ=τ’-1; when τ is less than τ min , then the adjusted aggregation level is equal to τ+1.
[0103] When the adjustment module 203 exceeds the adjustment range of the aggregation level, the transmission power of the PDCCH is adjusted in the following manner:
[0104] Case 1:
[0105] The current aggregation level τ is greater than τ max , PDCCH transmit power after adjustment = PDCCH transmit power before adjustment + transmit power adjustment step size. The transmission power adjustment step size is preset.
[0106] Case two:
[0107] The current aggregation level τ is less than τ min , PDCCH transmit power after adjustment = PDCCH transmit power before adjustment - transmit power adjustment step size.
[0108] The above descriptions are merely preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.
