Transmission method for physical downlink control channel

A physical downlink control and control channel technology, applied in wireless communication, multi-frequency code systems, electrical components, etc., can solve the problems of limited number of UEs, limited control channel transmission capacity, affecting MU-MIMO and CoMP performance gains, etc. The effect of increasing capacity

Active Publication Date: 2013-02-13
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AI-Extracted Technical Summary

Problems solved by technology

In the prior art, the number of UEs that can be carried by CRS-based PDCCH is limited, which seriously affects the performance gain of MU-MIMO and CoMP
At the same time, in the heterogeneous scenario, the PDCCH demodulated based on CRS is strong...
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The invention provides a transmission method for a physical downlink control channel (PDCCH). The transmission method comprises the following steps that: (A) a network side sets a control channel indicator field (CCIF) for indicating the control information of user equipment (UE), and bears the contents of the PDCCH on an orthogonal frequency division multiplexing symbol of a physical downlink shared channel (PDSCH); and (B) the UE decodes the CCIF, determines the modulation mode and position of the control information, and acquires the contents of the PDCCH from the PDSCH according to the position. According to the scheme, the PDCCH bearing capacity of a sub-frame can be remarkably improved.

Application Domain

Multi-frequency code systemsWireless communication

Technology Topic

TelecommunicationsControl channel +3


  • Transmission method for physical downlink control channel
  • Transmission method for physical downlink control channel
  • Transmission method for physical downlink control channel


  • Experimental program(1)

Example Embodiment

[0021] The core idea of ​​the technical scheme of the present invention is to design a "control channel indication field" (CCIF) to indicate the control information of the UE. The CCIF contains a small amount of indication information. /9/10 UE has the same number of CCEs to ensure backward compatibility; at the same time, the control channel indicator field is only placed in the UE-specific search space, which reduces the number of blind detections, reduces the complexity of the UE and saves energy consumption, and the physical downlink of the UE The content domain information of the control channel is carried on the original PDSCH, which significantly improves the capacity of the subframe to carry the PDCCH. The transmission strategy based on the demodulation reference signal DMRS (Demodulation Reference Signal) is used, that is, the D-PDCCH solution is introduced (through DM-based -RS demodulation PDCCH), compared with the PDCCH scheme based on CRS demodulation in Rel-8/9/10, can obtain beamforming gain and improve demodulation performance, which is beneficial to Rel-11MU-MIMO and CoMP enhancement technology The introduction of, at the same time, can reduce the interference of heterogeneous networks to control channels.
[0022] The channel structure proposed by the embodiment of the present invention is as follows figure 2 Shown. Define the Rel-11 UE "Control Information Indication Area" (CCIF). CCIF contains the indication information of the user's PDCCH. The UE determines the corresponding D-PDCCH position according to this information. The user first decodes the CCIF and determines the modulation mode and position of the control information. The control channel information is located in the Rel-8/9/10 data channel (PDSCH), and the control information is decoded based on DMRS, and data transmission is performed according to the control information instruction. D-PDCCH does not use spatial multiplexing, only single-layer transmission. The UE adopts Rel-8/9/10 PDCCH transmission or DMRS-based PDCCH transmission will be indicated according to higher layer signaling. The possible resources and locations of D-PDCCH are configured by RRC.
[0023] The CCIF is carried on the control channel of Rel-8/9/10. According to the control channel processing method of Rel-8/9/10, the unit is controlled by the control channel unit (CCE) (the possible aggregation levels are 1, 2, 4, 8 ).
[0024] The Rel-11 UE defines a new D-PDCCH RNTI for PDCCH indication. For 1 group (including N) UEs use the same D-PDCCH Radio Network Temporary Identity (RNTI), such as image 3 Shown.
[0025] The D-PDCCH indicator field adopts the same processing method as Rel 8/9/10, and the code matches the CCE, so that backward compatibility can be guaranteed. D-PDCCH RNTI attaches a 16-bit cyclic redundancy check bit (CRC), and the control information indicator field of each user includes:
[0026] (1) Modulation mode indication field 1bit: 0 indicates QPSK, 1 indicates 16QAM, which is used to indicate the modulation mode adopted by the D-PDCCH.
[0027] (2) The D-PDCCH position indicator bit is coded according to the number of available resources.
[0028] There are two solutions for cascading CCIF of multiple UEs and sorting:
[0029] Solution 1: The sequence number of the UE in the group is determined according to the user C-RNTI
[0030] The eNB determines the number (N) of UEs included in each group according to the information bit length of the UE’s CCIF. Through scheduling, the C-RNTI of the UE is used to modulate N, and N UEs with different modulus values ​​are selected as a group. They are placed in cascade from small to large, and a D-PDCCH RNTI is allocated.
[0031] Solution 2: When D-PDCCH RNTI is allocated, the sequence number of the UE in the group is designated.
[0032] The UE uses D-PDCCH RNTI or C-RNTI (or SPS-RNTI) to decode control information in the UE-specific search space, which will be configured by RRC.
[0033] The CCIF indicator field is only placed in the UE-specific search space, and the UE only detects CCIF of one length. Therefore, the aggregation levels for the UE-Specific search space are 1, 2, 4, and 8 (candidate levels are 6, 6, 2 respectively) , 2) The maximum number of blind detection times is 16, which is significantly lower than the number of blind detection times of Rel8/9, which helps to reduce the decoding complexity and power consumption of the UE.
[0034] The UE decodes the CCIF information according to the D-PDCCH RNTI, reads the CCIF value according to its serial number, and determines the D-PDCCH position according to the value.
[0035] There are two solutions:
[0036] Solution 1: The minimum granularity of D-PDCCH is 1 RB, that is, the unit of control channel particles (D-CCE) based on DM-RS demodulation is defined as 1 RB, and the content of D-PDCCH will be carried out within 1 RB Rate matching. The number M of D-PDCCH resources and the corresponding positions are semi-statically configured by RRC. In the case of defining a sufficiently large D-CCE, each D-PDCCH carried in one D-CCE can ensure performance, and the UE will directly demodulate the control information according to the position of the D-PDCCH.
[0037] Scheme 2: Allocate M RBs as D-PDCCH resources, the unit of control channel particles is P sub-carriers, each RB contains K Rel-11 control channel particles (K*P=12), so there are M*K D -CCE, the D-PDCCH of the UE occupies L control channel particles, then the UE can use L×P subcarriers to carry the D-PDCCH. In the case of defining small-scale D-CCEs, the D-PDCCH of one UE can be carried in multiple D-CCEs, and the D-PDCCH that occupies multiple D-CCEs can be obtained through blind detection. The number of detections depends on the channel. Situation and D-CCE size, that is, when 1, 2, 4, 8 D-CCEs are defined, the UE will start with 1 D-CCE, 2 D-CCEs, ..., 8 D-CCEs according to the starting position. Blind detection, demodulate its control information.
[0038] In the embodiment of the present invention, the DM-RS port is obtained in an implicit manner.
[0039] For the allocated D-CCE for transmitting D-PDCCH, the corresponding DM-RS port number is allocated according to the frequency domain from high to low (or from low to high), using Rel-10 port 7 to port 14, a total of 8 Port, that is, the first D-PDCCH CCE uses port 7, and the second D-PDCCH CCE uses port 8.... If the number of allocated D-CCEs is greater than 8, the DM-RS port numbers are cyclically placed, and the UE obtains the sequence number of the D-CCEs through modulo operation according to the value in the CCIF, and obtains the corresponding DM-RS port number.
[0040] For the first D-CCE, only the 16QAM modulation mode is scheduled. If a UE is not scheduled in a subframe, the bits are all set to 0.
[0041] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the present invention Within the scope of protection.


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