Patent ID: 12207239

DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS

Part of the embodiments of the disclosure will be described in detail below with accompanying drawings. For the reference numerals used in the following description, the same reference numerals appearing in different drawings will be regarded as the same or similar elements. These embodiments are only a part of the disclosure and do not disclose all possible implementations of the disclosure.

FIG.1is a schematic diagram of an uplink signal time difference adjustment system1according to an embodiment of the disclosure. With reference toFIG.1, the uplink signal time difference adjustment system1includes a base station10, a user apparatus UE1, a user apparatus UE2, and a user apparatus UE3, but the number of user apparatuses is not limited thereto. The base station10has a time slot boundary SB. Each of the user apparatuses UE1, UE2, and UE3is connected to the base station10via wireless communication. The user apparatuses UE1, UE2, and UE3are, for example but not limited to, electronic apparatuses that may be connected to a base station via wireless communication such as tablet computers, smart phones, or the like.

The distance between each of the user apparatuses UE1, UE2, UE3and the base station10is different. Therefore, downlink signals received by the user apparatuses UE1, UE2, and UE3from the base station10have different delay times ta1, ta2, and ta3depending on their respective distances from the base station10. Similarly, uplink signals UL1, UL2, and UL3transmitted by the user apparatuses UE1, UE2, and UE3to the base station10have different delay times ta1, ta2, and ta3depending on their respective distances from the base station10while arriving at the base station10. Among the above, the delay times of the downlink signals are roughly the same as the delay times of the uplink signals.

Uplink signals ULd1, ULd2, and ULd3shown inFIG.1refer to the uplink signals UL1, UL2, and UL3of which arrival at the base station10is delayed. The base station10respectively detects the uplink signals UL1, UL2, and UL3with a physical layer. With the time slot boundary SB as the benchmark, according toFIG.1, the uplink signal ULd1is delayed by the first delay time ta1, the uplink signal ULd2is delayed by the first delay time ta2, and the uplink signal ULd3is delayed by the first delay time ta3.

FIG.2is a schematic diagram of the uplink signal time difference adjustment system1according to an embodiment of the disclosure. As shown inFIG.2, the base station10includes a media access control layer. Due to the limited resolution of the media access control layer of the base station10, the physical layer of the base station10extracts the uplink signals ULd1, ULd2, and ULd3merely at multiple fixed sampling points S, and the sampling points S are related to the resolution of a control element of the media access control layer. For example, assuming that the resolution of the media access control layer of the base station10is 6 bits, then there are31sampling points on each divided half with the time slot boundary SB as a center. Therefore, the base station10adjusts arrival times of the uplink signals ULd1, ULd2, and ULd3by the control element of the media access control layer. Taking the uplink signal ULd1as an example, the base station10transmits the adjustment of the uplink signal ULd1required by the control element to the user apparatus UE1through a downlink signal (not illustrated). Next, the user apparatus UE1adjusts the time of transmitting an uplink signal according to the downlink signal and transmits an uplink signal UL1′ to the base station10. Similarly, the base station10also adjusts the uplink signals ULd2and ULd3, and the user apparatuses UE2and UE3transmit uplink signals UL2′ and UL3′ to the base station10. According toFIG.2, with the time slot boundary SB as the benchmark, the uplink signal UL1′ is delayed by a second delay time ta1*, the uplink signal UL2′ is delayed by a second delay time ta2*, and the uplink signal UL3′ is delayed by a second delay time ta3*.

FIG.3is a schematic diagram of the uplink signal time difference adjustment system1according to an embodiment of the disclosure. As shown inFIG.3, the base station10respectively calculates time offsets E1, E2, and E3between the first delay times ta1, ta2, ta3and the second delay times ta1*, ta2*, ta3* corresponding to the user apparatuses UE1, UE2, and UE3.

FIG.4is a schematic diagram of the uplink signal time difference adjustment system1according to an embodiment of the disclosure. As shown inFIG.4, the base station10calculates a time slot boundary adjustment taadjaccording to the time offsets E1, E2, and E3, and adjusts the time slot boundary SB to a time slot boundary SB′ according to the time slot boundary adjustment taadj. It should be noted that the smaller the time offsets E1, E2, and E3, the closer the times of the uplink signals UL1′, UL2′, and UL3′ arriving at the base station10to the sampling points S. On the contrary, the greater the time offsets E1, E2, and E3, the farther the times of the uplink signals UL1′, UL2′, and UL3′ arriving at the base station10away from the sampling points S.

In an embodiment, the base station10respectively forms an offset vector according to the time offsets E1, E2, . . . , EU corresponding to the user apparatuses UE1, UE2, . . . UEU. For example, the base station10forms an offset vector {right arrow over (ta ta*)} according to the first delay times ta1, ta2, . . . , taUand the second delay times ta1*, ta2*, . . . , taU* corresponding to the user apparatuses UE1, UE2, . . . , UEU as shown below:
{right arrow over (ta ta*)}=(ta1*−ta1,ta2*−ta2, . . . ,ta|U|*−ta|U|)

Among the above, U is a total number of user apparatuses.

In addition, the base station10also forms a weight matrix w according to weights w1, . . . , w|U|corresponding to the user apparatuses UE1, UEU as shown below:

w=[w1…0⋮⋱⋮0…w❘"\[LeftBracketingBar]"U❘"\[RightBracketingBar]"]

Among the above, those skilled in the art may set the corresponding weights w1, . . . , w|U|, according to the importance of the user apparatuses UE1, UEU. For example, in an uplink signal, if the signaling radio bearer (SRB) requirement is greater than the data radio bearer (DRB), a weight may be set according to SRB/DRB or according to a signal demodulation mode.

After gaining the offset vector {right arrow over (ta ta*)} and the weight matrix w, the base station10obtains the minimum value according to a product of the offset vector {right arrow over (ta ta*)} and the weight matrix w by a vector norm. The vector norm is a method of converting a vector into a scalar. The base station10obtains the minimum value (scalar) from the product of the offset vector {right arrow over (ta ta*)} and the weight matrix w by the vector norm, such as min∥w·{right arrow over (ta ta*)}∥p. With min∥w·{right arrow over (ta ta*)}∥pas the time slot boundary adjustment taadj, the time slot boundary SB is adjusted to the time slot boundary SB′ according to the time slot boundary adjustment taadj.

FIG.5is a schematic diagram of the uplink signal time difference adjustment system1according to an embodiment of the disclosure. As shown inFIG.5, taking the uplink signal ULd3as an example, the base station10transmits the adjustment of the uplink signal ULd3required by the control element to the user apparatus UE3through a downlink signal (not illustrated) according to the sampling points S. Next, the user apparatus UE3adjusts the time of transmitting the uplink signal UL3′ to the base station10according to the downlink signal, and the base station10detects the second delay time ta3*of arrival of the uplink signal UL3′. The base station10calculates the time offset E3between the first delay time ta3and the second delay time ta3* corresponding to the user apparatus UE3. According toFIG.5, since the time slot boundary SB of the base station10has been adjusted to the time slot boundary SB′, with the time slot boundary SB′ as the benchmark, the time offset E3between the first delay time ta3and the second delay time ta3* corresponding to the user apparatus UE3has been eliminated, which means the uplink signal UL3′ of the user apparatus UE3may be extracted by the physical layer of the base station10as soon as arriving at the base station10.

However, since the time slot boundary SB of the base station10has been adjusted to the time slot boundary SB′, with the time slot boundary SB′ as the benchmark, the second delay time ta1* of the uplink signal UL1′ and the second delay time ta2* of the uplink signal UL2′ are also be changed, such that the time offsets E1and E2between the first delay times ta1, ta2and the second delay time ta1*, ta2* corresponding to the user apparatuses UE1and UE2are changed accordingly. With reference toFIG.4andFIG.5together, after the time slot boundary SB of the base station10is adjusted to the time slot boundary SB′, the time offset E2is also reduced, which means the time of the uplink signal UL2′ arriving at the base station10is closer to the sampling points S. However, the time offset E1has increased, which means the time of the uplink signal UL1′ arriving at the base station10is farther from the sampling points S.

During the communication between the base station10and the user apparatuses through the uplink signals and the downlink signals, the base station10continues the adjustment according to the uplink signal of each user apparatus. Therefore, the base station keeps adjusting the time slot boundary SB to reduce uplink time deviation of all user apparatuses.

In an embodiment, without violating QoS principles, the media access control layer of the base station10may group the user apparatuses.FIG.6Ais a schematic diagram of user apparatuses in the uplink signal time difference adjustment system1according to an embodiment of the disclosure. As shown inFIG.6A, the base station10detects uplink signals UL1, UL2, UL3, and UL4of user apparatuses UE1, UE2, UE3, and UE4by the physical layer. According toFIG.6A, with the time slot boundary SB as the benchmark, the uplink signal ULd1is delayed by the first delay time ta1, the uplink signal ULd2is delayed by the first delay time ta2, the uplink signal ULd3is delayed by the first delay time ta3, and the uplink signal ULd4is delayed by a first delay time ta4.

The base station10adjusts the uplink signals ULd1, ULd2, ULd3, and ULd4, and then the user apparatuses UE1, UE2, UE3, and UE4transmit the uplink signals UL1′, UL2′, UL3′, UL4′ to the base station10. With the time slot boundary SB as the benchmark, the uplink signal UL1′ is delayed by the second delay time ta1*, the uplink signal UL2′ is delayed by the second delay time ta2*, the uplink signal UL3′ is delayed by the second delay time ta3*, and the uplink signal UL4′ is delayed by a second delay time ta4*. The base station10respectively calculates time offsets E1, E2, E3, and E4between the first delay times ta1, ta2, ta3, ta4and the second delay time ta1*, ta2*, ta3*, ta4* corresponding to the user apparatuses UE1, UE2, UE3, and UE4.

In an embodiment, the media access control layer of the base station10may group the user apparatuses UE1, UE2, UE3, and UE4according to the time offsets E1, E2, E3, and E4.FIG.6Bis a schematic diagram of random grouping of the user apparatuses in the uplink signal time difference adjustment system1according to an embodiment of the disclosure. As shown inFIG.6B, it is assumed that the media access control layer of the base station10randomly groups the user apparatus UE1and the user apparatus UE2into a user apparatus group UEG. In the user apparatus group UEG, the base station10calculates the time slot boundary adjustment taadjaccording to the time offset E1of the user apparatus UE1and the time offset E2of the user apparatus UE2, and adjusts the time slot boundary SB to the time slot boundary SB′ according to the time slot boundary adjustment taadj.

Furthermore, in the user apparatus group UEG, with the time slot boundary SB′ as the benchmark, the second delay time ta1* of the uplink signal UL1′ and the second delay time ta2* of the uplink signal UL2′ are changed as well, causing the time offsets E1and E2between the first delay time ta1, ta2and the second delay time ta1*, ta2* corresponding to the user apparatuses UE1and UE2to be changed accordingly. With reference toFIG.6AandFIG.6Btogether, in the user apparatus group UEG, after the time slot boundary SB of the base station10is adjusted to the time slot boundary SB′, the time offset E1becomes greater than that before grouping, and the time offset E2becomes smaller than that before grouping. Even if the time slot boundary SB of the base station10is adjusted to the time slot boundary SB′, this random grouping makes no difference in the distances between the times of the uplink signals UL1′, UL2′ arriving at the base station10and the sampling points S in the user apparatus group UEG, compared to those before grouping.

In view of this, a better grouping method may shorten the sampling period of the physical layer of the base station10. For example, assuming that the resolution of the media access control layer of the base station10is 6 bits, then there are31sampling points on each divided half with the time slot boundary SB as a center. The time offsets E1, E2, . . . , EU between the first delay times ta1, ta2, . . . , taUand the second delay times ta1*, ta2*, . . . , taU* corresponding to the user apparatuses UE1, UE2, UEU are relative to the time slot boundary SB. If the31sampling points on one half of the time slot boundary SB is divided into 10 time slots, and user apparatuses having time offsets in the same time slot are grouped into the same user apparatus group, then the time offsets corresponding to the user apparatuses in each user apparatus group are close to each other.

According toFIG.6A, the time offset E1corresponding to the user apparatus UE1is relatively close to the time offset E3corresponding to the user apparatus UE3, while the time offset E2corresponding to the user apparatus UE2is relatively close to the time offset E4corresponding to the user apparatus UE4. Therefore, the media access control layer of the base station10may conduct grouping according to the time offsets of the user apparatuses.

FIG.6Cis a schematic diagram of effective grouping of user apparatuses in an uplink signal time difference adjustment system according to an embodiment of the disclosure. As shown inFIG.6C, the media access control layer of the base station10groups the user apparatus UE1and the user apparatus UE3into a user apparatus group UEGa, and groups the user apparatus UE2and the user apparatus UE4into a user apparatus group UEGb.

In the user apparatus group UEGa, the base station10calculates a time slot boundary adjustment taadjaaccording to the time offset E1of the user apparatus UE1and the time offset E3of the user apparatus UE3, and adjusts the time slot boundary SB to a time slot boundary SBa according to the time slot boundary adjustment taadja. In this way, in the user apparatus group UEGa, with the time slot boundary SBa as the benchmark, the second delay time ta1* of the uplink signal UL1′ and the second delay time ta3* of the uplink signal UL3′ are also changed, causing the time offsets E1and E3between the first delay times ta1, ta3and the second delay times ta1*, ta3* corresponding to the user apparatuses UE1and UE3to be changed accordingly. With reference toFIGS.6A and6Ctogether, in the user apparatus group UEGa, after the time slot boundary SB of the base station10is adjusted to the time slot boundary SBa, although there is no significant change in the time offset E3, the time offset E1is significantly reduced. This means in the user apparatus group UEGa, the times of the uplink signals UL1′ and UL3′ arriving at the base station10are close to the sampling points S, which may reduce sampling errors of the physical layer of the base station10.

Similarly, in the user apparatus group UEGb, the base station10calculates a time slot boundary adjustment taadjbaccording to the time offset E2of the user apparatus UE2and the time offset E4of the user apparatus UE4, and adjusts the time slot boundary SB to a time slot boundary SBb according to the time slot boundary adjustment taadjb. In this way, in the user apparatus group UEGb, with the time slot boundary SBb as the benchmark, the second delay time ta2* of the uplink signal UL2′ and the second delay time ta4* of the uplink signal UL4′ are also changed, causing the time offsets E2and E4between the first delay times ta2, ta4and the second delay times ta2*, ta4* corresponding to the user apparatuses UE2and UE4to be changed accordingly. With reference toFIG.6AandFIG.6Ctogether, in the user apparatus group UEGb, after the time slot boundary SB of the base station10is adjusted to the time slot boundary SBb, both the time offsets E2and E4are significantly reduced. This means in the user apparatus group UEGb, the times of the uplink signals UL2′ and UL4′ arriving at the base station10are close to the sampling points S, which may reduce sampling errors of the physical layer of the base station10.

FIG.7is a flowchart of an uplink signal time difference adjustment method7shown in an embodiment of the disclosure. As shown inFIG.7, in step S710, a base station detects each first delay time of arrival of each uplink signal based on a time slot boundary. In step S720, each second delay time of each uplink signal is adjusted according to multiple sampling points. In step S730, each time offset between each first delay time and each second delay time corresponding to each user apparatus is calculated. In step S740, the time slot boundary is adjusted according to each time offset.

In an embodiment, the base station further includes a physical layer and a media access control layer. The sampling points S are related to the resolution of a control element of the media access control layer. The media access control layer notifies the physical layer to adjust the time slot boundary according to each time offset.

FIG.8is a flowchart of adjusting the second delay times in step S720in the uplink signal time difference adjustment method illustrated inFIG.7according to an embodiment of the disclosure. As shown inFIG.8, in step S721, each downlink signal is transmitted to each user apparatus according to the sampling points. In step S722, each user apparatus adjusts the time of arrival of each uplink signal at the base station according to each downlink signal. In step S723, the base station detects each second delay time of arrival of each uplink signal.

In an embodiment, the uplink signal time difference adjustment method further includes grouping each user apparatus into multiple user apparatus groups according to each time offset corresponding to each user apparatus. In each user apparatus group, the time slot boundary relative to each user apparatus group is adjusted according to each time offset of each user apparatus in each user apparatus group.

In an embodiment, the uplink signal time difference adjustment method further includes forming an offset vector according to each time offset corresponding to each user apparatus, setting a weight corresponding to each user apparatus to form a weight matrix, obtaining the minimum value from a product of the offset vector and the weight matrix by a vector norm, and adjusting the time slot boundary according to the minimum value.

In summary, the uplink signal time difference adjustment system and method provided in the disclosure may enable the base station to modulate uplink signals without being limited by the resolution of the media access control layer of the base station. The time slot boundary is adjusted according to the difference between the original delay time and the delay time adjusted by the control element of the media access control layer corresponding to each user apparatus, thereby reducing the time difference of the uplink signals between the base station and the user apparatuses and improving the performance of the base station in modulating the uplink signals. In addition, through the timing fine-tuning mechanism of the base station, the granularity problem of the user apparatuses is fixed to improve the SINR of the base station system.

It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the disclosed embodiments without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the disclosure cover modifications and variations of this disclosure provided they fall within the scope of the following claims and their equivalents.