JP6850327B2 - Wireless communication method and wireless communication device - Google Patents

Description

The present disclosure relates to the field of wireless communication, in particular to wireless communication methods and devices in machine-type communication.

Machine-Type Communication (MTC) is a new type of communication in Release 12 of The 3rd Generation Partnership Project (3GPP), an important source of revenue for operators, and an operator's perspective. Has great potential. Based on market and operator requirements, one of the key requirements of MTC is to improve the coverage of MTC's User Equipment (UE). Therefore, MTC is further envisioned in Release 13 to support coverage enhancement of, for example, 15 dB. This type of coverage extension technology is very useful for some MTC UEs, such as underground sensors, where there is a large loss of signal strength due to penetration loss.

Repetition is one of the key technologies for supporting MTC UEs in coverage enhancement. Specifically, in the case of an MTC UE in coverage expansion, each channel basically needs to perform a plurality of repetitions (for example, 100 times). On the receiver side, the receiver combines all the repetitions of the channel to decode the information. Therefore, the coverage extension requirement is achieved by signal accumulation and power enhancement due to repetition.

One non-limiting and exemplary embodiment provides a method for maximizing system performance in an MTC with extended coverage.

In the first general aspect of the present disclosure, a wireless communication method including a step of transmitting a reference signal and a data signal in a physical resource block (PRB) at a coverage extension level is provided, and the reference signal in the PRB is used. The number of resource elements to send is determined by the coverage extension level, channel type, and / or code rate of the data signal.

In the second general aspect of the present disclosure, a wireless communication method including a step of receiving a reference signal and a data signal in a physical resource block (PRB) transmitted at a coverage extension level is provided, and the PRB. The number of resource elements that transmit the reference signal is determined by the coverage extension level, channel type, and / or the code rate of the data signal.

A third general aspect of the present disclosure provides a wireless communication device comprising a transmission unit configured to transmit reference and data signals in a Physical Resource Block (PRB) at the coverage extension level. , The number of resource elements transmitting the reference signal in the PRB is determined by the coverage extension level, the channel type, and / or the code rate of the data signal.

In a fourth general aspect of the present disclosure, a wireless communication device comprising a receiving unit configured to receive reference and data signals in a Physical Resource Block (PRB) transmitted at an extended coverage level. The number of resource elements that transmit the reference signal in the PRB is determined by the coverage extension level, the channel type, and / or the code rate of the data signal.

It should be noted that general or specific embodiments may be implemented as systems, methods, integrated circuits, computer programs, storage media, or any selective combination thereof.

Further benefits and benefits of the disclosed embodiments will be apparent from the specification and drawings. Benefits and / or benefits can be obtained individually by various embodiments and features of the specification and drawings, all of which need to be provided in order to obtain one or more of such benefits and / or benefits. There is no.

The above and other features of the present disclosure, together with the accompanying drawings, will be more fully apparent from the following description and the appended claims. Understanding that these drawings show only some embodiments according to the present disclosure and therefore should not be construed as limiting their scope, the present disclosure is made more specific by use of the accompanying drawings. Let me explain in detail.

It is the schematic which shows the example of the BLER characteristic of PUSCH repetition. It is a flowchart of the wireless communication method by one Embodiment of this disclosure. It is a flowchart of the wireless communication method by another embodiment of this disclosure. It is a block diagram which shows the wireless communication apparatus by the further embodiment of this disclosure. It is a block diagram which shows the wireless communication apparatus by still another Embodiment of this disclosure.

In the following detailed description, reference is made to the accompanying drawings that form part of this specification. Unless the context dictates otherwise, the same reference numerals generally identify the same components in the drawings. It is readily understood that aspects of the present disclosure may be arranged, replaced, combined and designed in a wide variety of different configurations, all of which are expressly intended and form part of the present disclosure. are doing.

<Basic knowledge that is the principle of this disclosure>
As mentioned in the background technology, in repetition, which is one of the important technologies for expanding the coverage of MTC, long repetition continues for a long time, and the UE of MTC keeps active state for a long time to keep it in the receiving state at all times. You will be required to do so. This consumes a lot of UE power and occupies a lot of system resources. Therefore, in order to realize the coverage expansion in order to reduce the number of repetitions, other coverage expansion techniques such as an increase in the reference signal (RS) density (density) are effective.

In order to introduce a simple increase in RS density, one physical resource block (PRB) is taken as an example. One PRB is composed of 14 symbols in the time domain and 12 subcarriers in the frequency domain, and one symbol and one subcarrier form one resource element (RE: Resource Element). That is, one PRB has a total of 12 × 14 REs. The standard specifies that in one PRB, some REs are assigned to transmit some types of reference signals and others are assigned to transmit data signals. For a particular reference signal under normal usage, the standard specifies the number and position of REs assigned to transmit the reference signal in one PRB. Therefore, the RS density, that is, the ratio of REs for transmitting a reference signal to all REs in one PRB, is specified in the standard. Therefore, increasing the RS density means increasing the number of REs for transmitting a reference signal in one PRB.

By increasing the RS density, channel estimation performance and signal quality can be improved, and thus the number of repetitions of the MTC UE with extended coverage can be reduced.

One direct solution for increasing RS density is for all UEs and all channels to have RE and 24 Cell-specific Reference Signals (CRSs), eg, per PRB. It is to assume the maximum RS density having RE of the demodulation reference signal (DMRS) of. However, based on our consideration, some UEs cannot benefit from the increased RS density, but their performance will be affected. Also, some channels cannot benefit from the increased RS density due to their impact on the code rate. A detailed discussion will be given below.

The first consideration is based on a simulation of the Physical Uplink Shared Channel (PUSCH) for different number of repetitions and subframes combined on the receiver side for demodulation. FIG. 1 is a schematic view showing an example of a block error rate (BLER) characteristic of PUSCH repetition.

As shown in FIG. 1, FIG. 1 (a) on the left side and FIG. 1 (b) on the right side show simulation curves corresponding to two different repetition cases. In each case, the horizontal axis represents the average signal-to-noise ratio (SNR), and the vertical axis represents the average BLER. Simulation parameters are specifically shown in the lower left corners of both FIGS. 1 (a) and 1 (b). Simulation parameters of FIGS. 1 (a) and 1 (b), except that the number of repetitions in FIG. 1 (a) is N _Rep = 8 and the number of repetitions in FIG. 1 (b) is N _{Rep = 128.} Is the same.

Also, as shown in the upper right corner of FIGS. 1 (a) and 1 (b), the _Wave parameter is the number of subframes synthesized on the receiver side for joint channel estimation. Represents. Specifically, in FIG. 1A, in the case of 8 repetitions, the dotted curve corresponds to the ideal channel estimation, and the solid three curves are combined on the receiver side for joint channel estimation. It corresponds to realistic channel estimation when the number of subframes to be made is equal to 1, 4 and 8, respectively. Similarly, in FIG. 1 (b), for 128 repetitions, the dotted curve corresponds to the ideal channel estimation, and the three solid curves are combined on the receiver side for joint channel estimation. It corresponds to realistic channel estimation when the number of subframes is equal to 1, 4 and 8, respectively.

Intuitively, by comparing FIG. 1 (a) and FIG. 1 (b), eight repetitions for the same average BLER, regardless of ideal channel estimation and realistic channel estimation. The average SNR of is much higher than the average SNR of 128 repetitions. Also, in the case of the eight repetitions of FIG. 1 (a), the characteristic difference between the ideal channel estimation curve and the realistic channel estimation curve with the composition of four or eight subframes is , It is smaller than the case of 128 times in FIG. 1 (b). That is, the characteristic difference between the ideal channel estimation curve and the realistic channel estimation curve increases as the number of repetitions increases.

In particular, taking the average BLER = 10 ^-1 as an example, the channel estimation gain is obtained by comparing the curve of the ideal channel estimation and the curve _{of the case of Ave = 8 as shown by the double-headed arrow.} It is easy to see that in the case of 8 repetitions as shown in (a), it is only about 1 dB, and as shown in FIG. 1 (b), it reaches 6 to 7 dB in the case of 128 repetitions. That is, the channel estimation gain is considerably limited when the number of repetitions is small, but becomes large when the number of repetitions is large.

Although the simulation results are from uplink simulations, it should be noted that the above considerations are also valid for downlinks. That is, the improvement in channel estimation performance significantly improves the BLER characteristics in a low signal-to-noise ratio (SINR) scenario (for example, as shown in FIG. 1 (b)), but (as shown in FIG. 1 (b)). For example, in a relatively high SINR scenario (as shown in FIG. 1A), the effect on the characteristics is small.

Therefore, from the above considerations, as shown in FIG. 1 (a), the SINR is relatively high, not 0 or a small number of repetitions, or no or short repetitions (no or lower coverage extension level). , The SINR is relatively low as shown in FIG. 1 (b), and it is meaningful to increase the RS density for a higher number of repetitions or a longer repetition (higher coverage extension level).

The second consideration is based on the following example of Enhanced Physical Downlink Control Channel (EPDCCH).

As an example, assuming that EPDCCH is transmitted in one PRB with 120 available REs, the size of Downlink Control Information (DCI) is determined by Cyclic Redundancy Check (CRC). It is 26 bits, the modulation is QPSK (Quadrature Phase Shift Keying), and its equivalent coding rate is very low, about 26 / (120 × 2) = 0.108. In that case, to increase the RS density, some REs assigned to transmit the data signal are usually used to transmit the RS, which does not significantly affect the code rate. Is. For example, using 12 data REs to further transmit RS, the code rate was changed to 26 / ((120-12) × 2 = 0.120, which is still very low. The amount of change in the conversion rate is also very small at 0.012.

As another example, assuming that the EPDCCH is transmitted on one Enhanced Control Channel Element (ECCE) capable of carrying 36 REs, the DCI size is also 26 bits by CRC. The modulation is QPSK, and its equivalent coding rate is 26 / (36 × 2) = 0.361, which is relatively high compared to the above example. In this case, if 3 or 6 data REs are replaced for the RS RE, 26 / ((36-3) × 2) = 0.394 or 26 / ((36-6) × 2) = 0.433. The coding rate is changed to, which is also relatively high compared to the above example. Correspondingly, the amount of change in the coding rate is as high as 0.033 or 0.072. Therefore, replacing 3 or 6 data REs for RS REs has some effect on the characteristics of BLER. In that case, the channel estimation gain due to the increase in RS density can be less than the loss caused by the increased code rate.

Therefore, from the above consideration, it can be seen that when the coding rate is low (for example, the previous example), the increase in RS density is more appropriate than when the coding rate is high (for example, the later example). This is because the user equipment (UE: User Equipment) can benefit from the improvement in channel estimation performance due to the increase in RS density, although it has little effect on the low code rate.

Although the results of the above discussion are based on the downlink example, it should be noted that the above discussion is also valid for the uplink case.

Based on the above two considerations, in order to maximize the performance of the system, it is necessary to consider the conditions under which the increase in RS density is significant when adopting the increase in RS density.

In one embodiment of the present disclosure, a wireless communication method 20 as shown in FIG. 2 is provided. FIG. 2 is a flowchart of a wireless communication method according to an embodiment of the present disclosure. As shown in FIG. 2, the wireless communication method 20 includes a step S201 of transmitting a reference signal and a data signal in the PRB at the coverage extension level. In the wireless communication method 20, the number of resource elements transmitting the reference signal in the PRB is determined by the coverage extension level, the channel type, and / or the code rate of the data signal.

Specifically, as described above, one PRB contains a total of 12 × 14 REs, some of which are assigned to transmit a reference signal (RS) and others. Some are used to transmit data signals. For example, the RS may be a DMRS used to demodulate a transmit signal containing UE (receiver side) data. However, the RS is not limited to a specific RS such as DMRS, and may be any kind of RS. For example, when the wireless communication method 20 is used in MTC, RS may be CRS.

Further, for example, in an MTC with coverage extension, the coverage extension level is defined to indicate the level or degree of coverage extension. The higher the coverage expansion level, the greater the coverage expansion. More specifically, when using repetition to perform coverage expansion, the coverage expansion level may be represented by the number of repetitions. That is, the greater the number of repetitions used, the greater the coverage expansion and therefore the higher the coverage expansion level.

Furthermore, with respect to repetition, it is well known that the number of repetitions indicates the number of times RS and data signals are repeatedly transmitted in subframes or PRBs. One subframe consists of two slots, each slot containing seven symbols in the time domain, which is the same as one PRB. However, one PRB corresponds to 12 subcarriers in the frequency domain, and one subframe depends on the bandwidth in the frequency domain. Therefore, the repetition in the subframe means the repetition in the time domain only, and the repetition in the PRB means the repetition in both the time domain and the frequency domain. It should be noted that, although not illustrated here, the repetition may be performed only in the frequency domain.

Thus, according to one embodiment of the present disclosure, in wireless communication 20, the coverage extension level can be represented by the number of repetitions of transmission of reference and data signals in the time domain and / or frequency domain.

Repetition as one of the important technologies for coverage expansion is only for explanation, and the technology for coverage expansion is not limited to repetition, and other technologies may be used to carry out coverage expansion. Please note that it is good. When using other techniques, the coverage extension level may be represented by other parameters instead of the number of repetitions.

Further, the wireless communication method 20 is suitable for MTC, but is not limited to MTC. This can be applied to any wireless communication with extended coverage.

As mentioned above, the number of REs transmitting RS in the PRB can be determined by the coverage extension level, channel type, and / or code rate of the data signal. That is, one or any combination of the three parameters is used to carry out the increase in RS density. Details of the three parameters will be described later.

In wireless communication 20, increasing RS density based on coverage expansion level, channel type, and / or data signal coding rate improves signal quality and reduces UE power consumption associated with coverage expansion. ..

According to one embodiment of the present disclosure, in the wireless communication 20 shown in FIG. 2, the number of resource elements transmitting the reference signal in the PRB for the larger coverage extension level is greater than that for the smaller coverage extension level. May be many.

Specifically, as seen in the first consideration above, as shown in FIG. 1 (b), communication with a large coverage expansion level (for example, a large number of repetitions) has a relatively low SINR and channel estimation. In this case, increasing the RS density is meaningful, that is, more RS REs in the PRB are used to transmit the RS, as improved performance will significantly improve its BLER characteristics. Should be. On the other hand, as shown in FIG. 1A, the communication with a small coverage expansion level (for example, a small number of repetitions) has a relatively high SINR, and the improvement in the channel estimation performance has almost no effect on the BLER characteristics. In this case, there is no point in increasing the RS density, i.e., less RS RE in the PRB should be used to transmit the RS.

For the sake of clarity for those skilled in the art, a Physical Downlink Shared Channel (PDSCH) will be taken as an example. Below, Table 1 shows an exemplary use of RE for transmitting RS in PRBs based on coverage extension levels.

In Table 1, the first line gives five different coverage extension levels 1-5, and the second line shows RS configurations corresponding to coverage extension levels 1-5, respectively. Here, it is assumed that the coverage extension level 1 indicates the minimum level (for example, the minimum number of repetitions), and the coverage extension level 5 indicates the maximum level (for example, the maximum number of repetitions).

For minimum coverage extension level 1, the minimum number of REs in the PRB is used to transmit the RS, i.e., as mentioned above, the channel estimated gain due to the increase in RS density in this scenario is potential. The minimum RS density is used as it does not exist in. For example, as shown in Table 1, one or two DMRS ports, i.e. 12 DMRS REs, are used here as RS REs.

In the case of coverage extension level 2 larger than the minimum coverage extension level 1, the number of REs for transmitting RS in PRB can be increased as compared with the case of minimum coverage extension level 1. For example, as shown in Table 1, two or four DMRS ports, i.e. 24 DMRS REs, are used here as RS REs. The 24 DMRS REs are the largest DMRS RE configurations.

In the case of the coverage extension level 3 which is larger than the coverage extension level 2, the number of REs for transmitting the RS in the PRB can be further increased as in the case of the coverage extension level 2. For example, as shown in Table 1, in addition to 2 or 4 DMRS ports, ie 24 DMRS REs, 2 CRS ports, ie 16 CRS REs, are used here as RS REs. That is, in this case, there are a total of 40 RS REs in the PRB.

In the case of the coverage extension level 4 which is larger than the coverage extension level 3, the number of REs for transmitting the RS in the PRB can be further increased as in the case of the coverage extension level 3. For example, as shown in Table 1, two or four DMRS ports, ie 24 DMRS REs and four CRS ports, ie 24 CRS REs, are used herein as RS REs. That is, in this case, there are a total of 48 RS REs in the PRB. The 24 CRS REs are the maximum configuration of the CRS REs.

In the case of the maximum coverage extension level 5, the number of REs for transmitting RS in the PRB can be further increased as in the case of the coverage extension level 4. For example, as shown in Table 1, in addition to the maximum configuration of DMRS RE, that is, the maximum configuration of 24 DMRS RE and CRS RE, that is, 24 CRS RE, the channel state information reference signal (CSI-). A RE assigned to another RS, such as RS: Channel State Information Reference Signal), can be used here as the RE of the RS. That is, in this case, there are a total of 48 or more RS REs in the PRB.

In the RS configuration based on the coverage expansion level in Table 1, UEs that cannot benefit from the increased RS density do not suffer characteristic loss.

It should be noted that the coverage extension levels and the classification of the corresponding RS configurations in Table 1 are for illustration purposes only and the present disclosure is not limited thereto. The coverage extension level and the classification of the corresponding RS configuration can be changed according to the particular implementation.

Further, the determination of the number of RS REs in the PRB based on the coverage extension level has been specifically described by taking PDSCH as an example, but the present invention is not limited thereto. The present disclosure is also suitable, for example, for PUSCH and is applicable to any type of downlink and uplink.

The wireless communication 20 unnecessarily increases the RS density by determining the number of RS REs in the PRB based on the coverage expansion level, and the UE with a smaller coverage expansion level due to increased overhead and code rate. It is possible to avoid affecting the original performance of.

According to one embodiment of the present disclosure, in the wireless communication 20 shown in FIG. 2, at least a part of the reference signal transmitted in the PRB is an existing CRS, DMRS, CSI-RS, and / or other existing reference. The signal can be reused.

Reusing these existing RSs means not only using the REs assigned to transmit the existing RSs in the PRB, but also using these signals for channel estimation. Specifically, the RE configuration in the PRB for legacy RSs such as CRS, DMRS, and CSI-RS is defined in advance by the standard. These legacy RSs can be reused to increase the RS density.

For example, in the case of an MTC UE, the RS used for the MTC can reuse the existing CRS, DMRS, CSI-RS in response to a specific requirement for increased RS density. That is, RE of CRS, RE of DMRS, RE of CSI-RS and the like can be directly applied to RE that transmits RS of MTC in PRB. For example, as shown in Table 1, DMRS is reused for coverage extension levels 1 and 2. If it is necessary to increase the RS density of coverage extension levels 3 and 4, the CRS is additionally reused. DMRS, CRS and CSI-RS are all reused if the RS density at coverage extension level 5 needs to be further increased. In addition to the Legacy RS RE, these Legacy RS signals may be used directly in the MTC.

By reusing the legacy RS for the RS in wireless communication 20, the existing RS can be used as much as possible, avoiding increasing the RE of many additional RSs and thus guaranteeing resource utilization. To.

According to one embodiment of the present disclosure, in the wireless communication 20 shown in FIG. 2, at least a part of the reference signal transmitted in the PRB can be transmitted by the resource element used for transmitting the data signal. ..

Specifically, for example, if legacy RS cannot be used for MTC, RS can be transmitted using some REs assigned to transmit the data signal. For example, in the case of PDSCH in Table 1, it is assumed that only RE of DMRS is available. Therefore, for coverage extension level 3, the maximum configuration of DMRS REs, i.e. 24 DMRS REs, plus 16 REs assigned to transmit data signals, are used to make up the CRS REs. RS can be sent instead. The cases of coverage extension levels 4 and 5 are the same as those of coverage extension level 3.

Therefore, based on the availability of legacy RSs and the number of RSs to be increased, all RSs reuse legacy RSs, or some RSs reuse legacy RSs and the remaining RSs are in the PRB. Is transmitted in the RE of some data in, or all RSs are transmitted in the RE of some data in the PRB.

According to one embodiment of the present disclosure, in the wireless communication 20 shown in FIG. 2, the number of resource elements transmitting the reference signal in the PRB for a higher code rate is greater than that for a lower code rate. There are few.

Specifically, as seen in the second consideration above, when the RS density is increased, there is almost no effect on the low code rate, so that when the code rate is lower than when the code rate is high. , The increase in RS density becomes more reasonable. That is, when the code rate is low, it is necessary to use the RE of more RS of PRB to transmit the RS, and when the code rate is high, the RE of RS of less PRB is used. It is necessary to send RS.

The wireless communication 20 avoids unnecessarily increasing the RS density and causing characteristic loss in UEs with high code rates by determining the number of RS REs in the PRB based on the code rate. can do.

According to one embodiment of the present disclosure, in the wireless communication 20 shown in FIG. 2, the data signal is used for transmitting the PDSCH or PUSCH, and the usage of the resource element for transmitting the reference signal in the PRB is physically down. It is indicated by the MCS indicated by the DCI transmitted by the link control channel (PDCCH: Physical Downlink Control Channel) or EPDCCH.

Specifically, as will be readily appreciated by those skilled in the art, PDSCH will continue to employ an example in which PDSCH is transmitted in one PRB with 120 available REs and the modulation is assumed to be QPSK. The usage (configuration) of RS in this case can be shown in the MCS shown in the DCI transmitted on the PDCCH or EPDCCH. Next, Table 2 shows an example of an increase in RS density based on the coding rate shown by the Modulation and Coding Scheme (MCS).

In Table 2, the first column lists the MCS indexes 0-9, and the second column here gives the modulation order 2 for QPSK. Further, the third column shows the transport block size (TBS) indexes 0 to 9 corresponding to the MCS indexes 0 to 9 of the first column, and data of different sizes, that is, different data bits. Shows the number. Based on the number of bits indicated by each TBS index, as well as the conditions assumed above, the corresponding coding rate of each TBS index can be calculated by the same calculation method as in the second consideration above. The fourth column gives the calculated coding rates corresponding to the TBS indexes 0-9, respectively. For example, TBS index 0 and MCS index 0 correspond to a code rate of 0.067, TBS index 1 and MCS index 1 correspond to a code rate of 0.1, and TBS index 2 and MCS index 2 correspond to a code rate of 0. Corresponding to .134, TBS index 3 and MCS index 3 correspond to code rate 0.167, TBS index 4 and MCS index 4 correspond to code rate 0.233, and TBS index 5 and MCS index 5 correspond. Corresponding to code rate 0.3, TBS index 6 and MCS index 6 correspond to code rate N / A, TBS index 7 and MCS index 7 correspond to code rate 0.433, TBS index 8 and The MCS index 8 corresponds to a code rate of 0.5, and the TBS index 9 and the MCS index 9 correspond to a code rate of 0.567.

Based on the above discussion, the number of RS REs in the PRB for higher code rates must be smaller than that for lower code rates, and the increase in RS density is lower coding. Since it has little effect on the rate, the UE can benefit from the improved channel estimation due to the increased RS density without being affected by the increased coding rate.

In Table 2, column 5 gives the increased number of RS REs in different cases. Specifically, when the coding rates shown by the MCS indexes 0, 1, and 2, respectively, are as low as 0.067, 0.1, and 0.134, then the maximum increase in RE density is used, i.e. , 24 REs are added to transmit RS in PRB. Moderate increases in RE density are used when the coding rates indicated by MCS indexes 3, 4 and 5, respectively are 0.167, 0.233, and 0.3, i.e. RS in PRB. Twelve REs are added to send. If the coding rates indicated by the MCS indexes 6, 7, 8 and 9, respectively are as high as N / A, 0.433, 0.5, and 0.567, then the increase in RE density is not used, ie. , RE is not added to send RS in PRB. Therefore, as shown in Table 2, the usage of RE for transmitting RS (or increased RS density) in PRB can be indicated by MCS.

It should be noted that the increased number of RS REs in Table 2 (eg, 24 or 12 REs) is for illustration purposes only and the present disclosure is not limited thereto. Further, although PDSCH has been described as an example here, the present invention is not limited thereto. The present disclosure is also suitable, for example, for PUSCH and is applicable to any type of downlink and uplink data.

In addition, as mentioned above, the added 24 or 12 REs in this example either reuse the legacy RS, are transmitted in the RE of some data in the PRB, or part of the legacy RS. Can be reused and partially transmitted in the RE of some data in the PRB.

It is not necessary to configure new signaling to indicate the usage of RS by indicating the usage of RE to transmit RS in PRB by MCS.

According to one embodiment of the present disclosure, in the wireless communication 20 shown in FIG. 2, the usage of the resource element for transmitting the reference signal in the PRB may be configured by the radio resource control (RRC). It may be pre-defined or recommended by the user equipment via a channel quality indicator (CQI).

Specifically, an example showing the usage of RE for transmitting RS in PRB by MCS is shown above, but the present invention is not limited thereto. The detailed usage of RE in increased RS may be configured by RRC or may be pre-defined. Alternatively, the UE may recommend increasing the RS density via CQI. RRC and CQI are existing signaling such as MCS and their configurations are well known to those of skill in the art and will not be described in detail here to avoid redundancy. Similarly, there is no need to configure new signaling to indicate the usage of RS in this case.

As mentioned above, the number of REs transmitting RS in the PRB may be determined by the channel type of the data signal. That is, different channels may use different RS densities.

According to one embodiment of the present disclosure, in the wireless communication 20 shown in FIG. 2, the usage of the resource element in which the data signal is used for transmitting the PDCCH or EPDCCH and the reference signal is transmitted in the PRB is a system information block ( SIB: System Information Block) may be indicated or specified.

Specifically, PDCCH and PDSCH are taken as examples. Generally, PDCCH has a very low code rate, for example it is assumed that one PRB is used to transmit 26-bit DCI, while PDSCH uses a relatively high code rate to guarantee throughput. .. In this case, the PDSCH may typically use a standard RS density and the PDCCH may use an increased RS density. Therefore, the channel characteristics of PDSCH are unaffected. On the other hand, PDCCH has almost no characteristic loss, but can benefit from the improvement in channel estimation performance due to the increase in RS density.

In addition, detailed usage of RS RE for PDCCH may be indicated by SIB. Alternatively, detailed usage of RS RE for PDCCH may be specified, for example, in the specification. For example, for simplification, the maximum RS density (eg, 24 CRS REs and 24 DMRS REs) may always be assumed for PDCCH. Thus, there is no need to configure new signaling to show the detailed usage of RS RE for PDCCH.

Although PDCCH and PDSCH have been described here as examples, the present invention is not limited to this, and for example, the above design is also suitable for EPDCCH.

According to one embodiment of the present disclosure, in the wireless communication 20 shown in FIG. 2, the data signal can be used for the transmission of the SIB 1, and the usage of the resource element for transmitting the reference signal in the PRB is the master information block ( MIB: Master Information Block) may be indicated or specified.

Specifically, SIB is taken as an example. It is well known that the UE does not know the coverage extension level before or during SIB reception. In this case, it is not possible to determine the increase in RS density of SIB1 based on the coverage extension level before reception and demodulation of SIB1. Therefore, when transmitting SIB1 in PRB, the usage of RE for transmitting RS may be specified in the specification. For example, for SIB1, the maximum RS density (eg, RE for 24 CRS and RE for 24 DMRS) may always be assumed.

Alternatively, the usage of RE for transmitting RS for SIB1 may be indicated in the MIB. In this case, the receiver can first demodulate the MIB to obtain the usage of RE for transmitting the RS for SIB1 shown in the MIB for demodulation of SIB1. Then, the SIB1 is demodulated on the receiver side.

It is not necessary to set up new signaling indicating the detailed usage of RS RE for SIB1 by indicating or specifying the usage of RS RE in PRB for SIB1 in MIB.

According to one embodiment of the present disclosure, in the wireless communication 20 shown in FIG. 2, the usage of the resource element for transmitting the reference signal in the PRB for another SIB is indicated by the SIB1.

Specifically, since another SIB is obtained after SIB1, the usage of RE of RS in PRB for other SIB may be indicated by SIB1. In this way, after the SIB1 has been received on the receiver side, the usage of RS RE in the PRB for the other SIBs indicated by the SIB1 can be obtained to decode the other SIBs. Then, another SIB can be obtained on the receiver side.

By showing the usage of RE of RS in PRB for other SIBs by SIB1, a more flexible usage of RS of SIB is realized.

In another embodiment of the present disclosure, a wireless communication method 30 as shown in FIG. 3 is provided. FIG. 3 is a flowchart of a wireless communication method according to another embodiment of the present disclosure. As shown in FIG. 3, the wireless communication method 30 includes step S301 to receive the reference signal and the data signal in the PRB transmitted at the coverage extension level. In the wireless communication method 30, the number of resource elements transmitting the reference signal in the PRB is determined by the coverage extension level, the channel type, and / or the code rate of the data signal.

In wireless communication 30, signal quality is improved and UE power consumption associated with coverage expansion is reduced by increasing the RS density based on coverage expansion level, channel type, and / or data signal coding rate. ..

According to one embodiment of the present disclosure, in the wireless communication 30 shown in FIG. 3, the number of resource elements transmitting the reference signal in the PRB for a larger coverage extension level is greater than that for a smaller coverage extension level. There are many.

According to one embodiment of the present disclosure, in the wireless communication 30 shown in FIG. 3, the number of resource elements transmitting the reference signal in the PRB for a higher code rate is greater than that for a lower code rate. Few.

The other technical features of the wireless communication method 20 can also be incorporated into the wireless communication device 30.

In a further embodiment of the present disclosure, a wireless communication device 40 as shown in FIG. 4 is provided. FIG. 4 is a block diagram showing a wireless communication device 40 according to a further embodiment of the present disclosure.

As shown in FIG. 4, the wireless communication device 40 includes a transmission unit 401 configured to transmit reference and data signals in the PRB at the coverage extension level. The number of resource elements that transmit the reference signal in the PRB is determined by the coverage extension level, the channel type, and / or the code rate of the data signal.

The wireless communication device 40 according to the present disclosure is a central processing unit (CPU) 410, CPU 410 that processes various data in the wireless communication device 40 and executes a related program to control the operation of each unit. Read-only memory (ROM: Read Only Memory) 430 for storing various programs required to execute various processes and controls, and intermediate data temporarily generated by the processing and control procedures by the CPU 410 are stored. Random Access Memory (RAM) 450 for storing and / or a storage unit 470 for storing various programs, data, and the like may be further included. The transmission unit 401, CPU 410, ROM 430, RAM 450, and / or storage unit 470 and the like are interconnected via data and / or command bus 490, and signals can be transferred between them.

Each unit as described above does not limit the scope of the present disclosure. According to one embodiment of the present disclosure, the function of the transmission unit 401 may be realized by functional software in combination with the CPU 410, ROM 430, RAM 450, and / or storage unit 470 and the like.

In the wireless communication device 40, the signal quality is improved and the power consumption of the UE associated with the coverage expansion is reduced by increasing the RS density based on the coverage expansion level, the channel type, and / or the code rate of the data signal. To.

In yet another embodiment of the present disclosure, a wireless communication device 50 as shown in FIG. 5 is provided. FIG. 5 is a block diagram showing a wireless communication device 50 according to still another embodiment of the present disclosure.

As shown in FIG. 5, the wireless communication device 50 includes a receiving unit 501 configured to receive reference and data signals in the PRB transmitted at the coverage extension level. The number of resource elements that transmit the reference signal in the PRB is determined by the coverage extension level, the channel type, and / or the code rate of the data signal.

The wireless communication device 50 according to the present disclosure is for executing various processes and controls by the CPU 510 and the CPU 510 that execute related programs for processing various data in the wireless communication device 50 and controlling the operation of each unit. ROM 513 for storing various programs required for the device, RAM 515 for storing intermediate data temporarily generated in the processing and control procedure by the CPU 510, and / or storage for storing various programs and data. Unit 517 may be further included. The receiving unit 501, CPU 510, ROM 513, RAM 515, and / or storage unit 517 and the like are interconnected via data and / or command bus 520, and signals can be transferred between them.

Each unit as described above does not limit the scope of the present disclosure. According to one embodiment of the present disclosure, the function of the receiving unit 501 may be realized by functional software in combination with the CPU 510, ROM 513, RAM 515, and / or storage unit 517 and the like.

In the wireless communication device 50, the signal quality is improved and the power consumption of the UE associated with the coverage expansion is reduced by increasing the RS density based on the coverage expansion level, the channel type, and / or the code rate of the data signal. To.

The wireless communication device 40 and the wireless communication device 50 may be an eNB (eNodeB), a UE, or the like, depending on a specific application scenario. Further, the technical features of the wireless communication methods 20 and 30 can be incorporated into the wireless communication devices 40 and 50, respectively.

This disclosure may be achieved by software, hardware, or software in collaboration with the hardware. Each functional block used in the description of each embodiment described above can be realized by an LSI as an integrated circuit, and each process described in each embodiment may be controlled by the LSI. They may be individually formed as chips, or one chip may be formed to include some or all of the functional blocks. They may include data inputs and outputs coupled therein. Here, the LSI may be called an IC, a system LSI, a super LSI, or an ultra LSI depending on the degree of integration. However, the method for realizing the integrated circuit is not limited to the LSI, and may be realized by using a dedicated circuit or a general-purpose processor. In addition, a field programmable gate array (FPGA) that can be programmed after the LSI is manufactured, or a reconfigurable reconfigurable circuit cell arrangement and settings arranged inside the LSI. A processor may be used.

It is intended that this disclosure will be variously modified or modified by one of ordinary skill in the art based on the description presented in the specification and known techniques without departing from the spirit and scope of the present disclosure. Such changes and applications fall within the scope of the protected claims. Further, the components of the above-described embodiments can be arbitrarily combined without departing from the gist of the present disclosure.

The embodiments of the present disclosure can provide at least the following subjects:

(1). The process of transmitting reference and data signals in a physical resource block (PRB) at the coverage extension level,
It is a wireless communication method including
The number of resource elements that transmit the reference signal in the PRB is determined by the coverage extension level, channel type, and / or code rate of the data signal.

(2). The method according to (1), wherein the number of resource elements transmitting the reference signal in the PRB for a larger coverage extension level is greater than that for a smaller coverage extension level.

(3). At least a part of the reference signal transmitted in the PRB is an existing cell-specific reference signal (CRS), demodulation reference signal (DMRS), and channel state information reference signal (CSI-RS). : Channel State Information Reference Signal), and / or the method according to (1), which reuses an existing reference signal.

(4). The method according to (1), wherein at least a part of the reference signal transmitted in the PRB is transmitted in the resource element used to transmit the data signal.

(5). The method according to (1), wherein the number of resource elements transmitting the reference signal in the PRB for a higher code rate is less than that for a lower code rate.

(6). A resource element for transmitting a reference signal in a PRB where a data signal is used to transmit a Physical Downlink Shared Channel (PDSCH) or a Physical Uplink Shared Channel (PUSCH). Is used in Downlink Control Information (DCI) transmitted on the Physical Downlink Control Channel (PDCCH) or Enhanced Physical Downlink Control Channel (EPDCCH). The method according to (1), which is indicated by the modulation coding scheme (MCS) shown.

(7). The usage of the resource element that transmits the reference signal in the PRB is configured by Radio Resource Control (RRC) and is pre-defined by the user equipment via the Channel Quality Indicator (CQI). The recommended method according to (1).

(8). The data signal is used to transmit the PDCCH or EPDCCH, and the usage of the resource element that transmits the reference signal in the PRB is indicated or specified by the System Information Block (SIB). The method described in 1).

(9). The data signal is used to transmit the SIB1 and the usage of the resource element that transmits the reference signal in the PRB is indicated or specified by the Master Information Block (MIB), (1). The method described in.

(10). The method according to (1), wherein the usage of the resource element for transmitting the reference signal in the PRB for another SIB is indicated by SIB1.

(11). A wireless communication method including a step of receiving a reference signal and a data signal in a physical resource block (PRB) transmitted at a coverage extension level.
The number of resource elements that transmit the reference signal in the PRB is determined by the coverage extension level, channel type, and / or code rate of the data signal.

(12). 11. The method of (11), wherein the number of resource elements transmitting the reference signal in the PRB for a larger coverage extension level is greater than that for a smaller coverage extension level.

(13). 11. The method of (11), wherein the number of resource elements transmitting the reference signal in the PRB for a higher code rate is less than that for a lower code rate.

(14). A wireless communication device including a transmission unit configured to transmit a reference signal and a data signal in a physical resource block (PRB) at the coverage extension level.
The number of resource elements that transmit the reference signal in the PRB is determined by the coverage extension level, channel type, and / or code rate of the data signal.

(15). A wireless communication device including a receiving unit configured to receive a reference signal and a data signal in a physical resource block (PRB) transmitted at the coverage extension level.
The number of resource elements that transmit the reference signal in the PRB is determined by the coverage extension level, channel type, and / or code rate of the data signal.

(16). The method according to (1), wherein the coverage extension level is represented by the number of repetitions of transmission of reference and data signals in the time domain and / or frequency domain.

The technical features of the wireless communication method can be incorporated into the wireless communication device. Further, the embodiments of the present disclosure can also provide integrated circuits including modules for performing the steps in each of the above wireless communication methods. Further, an embodiment of the present invention may also provide a computer-readable storage medium that stores a computer program containing program code that executes the steps of each of the above wireless communication methods when executed on a computing device. it can.

Claims (16)

Identify the resource element used to transmit the reference signal in the Physical Resource Block (PRB).
Based on the coverage expansion level represented by the number of transmission repetition, to transmit a front Symbol reference signal and a data signal,
The reference signal includes a cell-specific reference signal (CRS) and a demodulation reference signal (DMRS).
When the coverage extension level is 2 or more, the density of the reference signal is set by adding CRS without changing the density of DMRS.
Wireless communication method. The number of resource elements of the reference signal which the coverage extension level is used in two or more, the coverage extension level is greater than the number of resource elements used in 1,
The wireless communication method according to claim 1. The number of the resource elements used for transmission of the previous SL reference signal is dependent Ji Yanerutaipu,
The wireless communication method according to claim 1. The density of the reference signal of the physical downlink control channel (PDCCH) is higher than the density of the reference signal of the physical downlink shared channel (PDSCH).
The wireless communication method according to claim 1. At least a portion of the reference signal to be transmit is transmitted in the resource elements used for transmission of the data signal,
The wireless communication method according to claim 1. The usage of the resource element used to transmit the reference signal is indicated by the System Information Block (SIB) .
The wireless communication method according to claim 1. Usage of the resource elements used for transmission of the previous SL reference signal, the physical downlink control channel (PDCCH: Physical Downlink Control Channel) or enhanced physical downlink control channel (EPDCCH: Enhanced Physical Downlink Control Channel ) transmitted in Modulation and Coding Scheme (MCS), which is indicated by Downlink Control Information (DCI).
The wireless communication method according to claim 1. The use of the resource elements used for transmission of the previous SL reference signal, a radio resource control (RRC: Radio Resource Control) by either configured or pre-defined, or a channel quality indicator (CQI: Channel Quality Recommended by user equipment via Indicator),
The wireless communication method according to claim 1. A control unit that identifies a resource element used for transmitting a reference signal in a physical resource block (PRB), and a control unit.
Based on the coverage expansion level represented by the number of transmit repetition, and a transmission unit for transmitting said reference signal and a data signal,
The reference signal includes a cell-specific reference signal (CRS) and a demodulation reference signal (DMRS).
When the coverage extension level is 2 or more, the control unit adds CRS without changing the density of DMRS to set the density of the reference signal.
Wireless communication device. The number of resource elements of the reference signal which the coverage extension level is used in two or more, the coverage extension level is greater than the number of resource elements used in 1,
The wireless communication device according to claim 9. The number of the resource elements used for transmission of the previous SL reference signal is dependent Ji Yanerutaipu,
The wireless communication device according to claim 9. The density of the reference signal of the physical downlink control channel (PDCCH) is higher than the density of the reference signal of the physical downlink shared channel (PDSCH).
The wireless communication device according to claim 9. At least a portion of the reference signal to be transmit is transmitted in the resource elements used for transmission of the data signal,
The wireless communication device according to claim 9. The usage of the resource element used to transmit the reference signal is indicated by the System Information Block (SIB).
The wireless communication device according to claim 9. Usage of the resource elements used for transmission of the previous SL reference signal, the physical downlink control channel (PDCCH: Physical Downlink Control Channel) or enhanced physical downlink control channel (EPDCCH: Enhanced Physical Downlink Control Channel ) transmitted in Modulation and Coding Scheme (MCS), which is indicated by Downlink Control Information (DCI).
The wireless communication device according to claim 9. The use of the resource elements used for transmission of the previous SL reference signal, a radio resource control (RRC: Radio Resource Control) by either configured or pre-defined, or a channel quality indicator (CQI: Channel Quality Indicator) by or recommended by the user equipment,
The wireless communication device according to claim 9.

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