Source: https://patents.justia.com/patent/10477554
Timestamp: 2020-01-29 00:16:03
Document Index: 302493418

Matched Legal Cases: ['art 1700', 'art 1800', 'art 1800', 'art 1900', 'art 1900', 'art 2000', 'art 2000', 'art 2100', 'art 2100', 'art 2200', 'art 2300', 'art 2300', 'art 2400', 'art 2400', 'art 2500', 'art 2600', 'Application No. 18152087']

US Patent for Method and apparatus for beam detection in a wireless communication system Patent (Patent # 10,477,554 issued November 12, 2019) - Justia Patents Search
Justia Patents Hand-off ControlUS Patent for Method and apparatus for beam detection in a wireless communication system Patent (Patent # 10,477,554)
Dec 29, 2017 - ASUSTek Computer Inc.
This application is a Divisional of U.S. patent application Ser. No. 15/004,370, filed Jan. 22, 2016, which claims the benefit of U.S. Provisional Patent Application Ser. No. 62/107,792 filed on Jan. 26, 2015, U.S. Provisional Patent Application Ser. No. 62/107,814 filed on Jan. 26, 2015, and U.S. Provisional Patent Application Ser. No. 62/166,368 filed on May 26, 2015, the entire disclosures of which are incorporated herein in their entirety by reference.
This disclosure generally relates to wireless communication networks, and more particularly, to a method and apparatus for beam detection in a wireless communication system.
Furthermore, EU started the METIS project in November 2012 to lay the foundation of 5G, the next generation mobile and wireless communications system. The main technical objectives (or 5G requirements) include the following:
1000 times higher mobile data volume per area;
10 to 100 times higher number of connected devices;
10 to 100 times higher user data rate;
10 times longer battery life for low power massive machine communications (MMC); and
5 times reduced End-to-End latency (<5 ms).
It is clear the above requirements demand much higher system capacity than what can be offered by the legacy systems. Thus, a new radio access technology can be expected to fulfill these requirements.
A method and apparatus for beam detection in a wireless communication system. In one embodiment, the method includes the UE initiating a random access (RA) procedure. The method also includes the UE transmitting multiple RA preambles to a base station of the cell at different occasions for the base station to determine a beam set of the UE. The method further includes the UE starts monitoring a Physical Downlink Control Channel (PDCCH) for RA response reception from the base station after finishing transmissions of the multiple RA preambles.
FIG. 5 illustrates a contention-based Random Access procedure.
FIG. 6 illustrates a contention-free Random Access procedure.
FIG. 7 is a reproduction of Figure 5.1-1 of 3GPP TS 36.300 V12.5.0.
FIG. 8 is a reproduction of Figure 5.1-2 of 3GPP TS 36.300 V12.5.0.
FIG. 9 is a reproduction of Table 5.1-1 of 3GPP TS 36.300 V12.5.0.
FIG. 10 is a reproduction of Figure 6.2.2-1 of 3GPP TS 36.211 V12.5.0.
FIG. 11 is a reproduction of Table 6.2.3-1 of 3GPP TS 36.211 V12.5.0.
FIG. 12 illustrates a physical subframe structure for a UDN (Ultra-Dense Network) system.
FIG. 13 is a diagram according to one exemplary embodiment.
FIG. 14 is a message flow diagram according to one exemplary embodiment.
FIG. 15 is a message flow diagram according to one exemplary embodiment.
FIG. 16 is a timing diagram according to one exemplary embodiment.
FIG. 19 is a flow chart according to one exemplary embodiment.
FIG. 20 is a flow chart according to one exemplary embodiment.
FIG. 21 is a flow chart according to one exemplary embodiment.
FIG. 22 is a flow chart according to one exemplary embodiment.
FIG. 23 is a flow chart according to one exemplary embodiment.
FIG. 24 is a flow chart according to one exemplary embodiment.
In particular, the exemplary wireless communication systems devices described below may be designed to support the wireless technology discussed in the various documents, including: “DOCOMO 5G White Paper” by NTT Docomo, Inc. Furthermore, the exemplary wireless communication systems devices described below may be designed to support one or more standards such as the standard offered by a consortium named “3rd Generation Partnership Project” referred to herein as 3GPP, including: R2-145410, “Introduction of Dual Connectivity”, NTT Docomo, Inc., NEC; TS 36.321 V12.3.0, “E-UTRA MAC protocol specification”; TS 36.213 V12.3.0, “E-UTRA Physical layer procedures”; TS 36.300 V12.5.0, “E-UTRA and E-UTRAN Overall description”; TS 36.211 V12.5.0, “E-UTRA Physical channels and modulation”; and METIS Public Deliverable D2.4 “Proposed solutions for new radio access”. The standards and documents listed above are hereby expressly incorporated by reference in their entirety.
The DOCOMO 5G White Paper introduces a 5G radio access concept that efficiently integrates both lower and higher frequency bands. Since higher frequency bands provide opportunities for wider spectrum but have coverage limitations because of higher path loss, it was proposed that a 5G system has a two-layer structure which consists of a coverage layer (e.g., consisting of macro cells) and a capacity layer (e.g., consisting of small cells or phantom cells). The coverage layer uses existing lower frequency bands to provide basic coverage and mobility. The capacity layer uses new higher frequency bands to provide high data rate transmission. The coverage layer could be supported by enhanced LTE RAT (Long Term Evolution Radio Access Technology), while the capacity layer could be supported by a new RAT dedicated to higher frequency bands. Furthermore, integration of the coverage and capacity layers is enabled by the tight interworking (e.g., dual connectivity) between the enhanced LTE RAT and the new RAT.
Dual connectivity is a mode of operation for a UE (User Equipment) in RRC_CONNECTED, configured with a Master Cell Group and a Secondary Cell Group as discussed in 3GPP R2-145410. A Master Cell Group is a group of serving cells associated with the MeNB (Master Evolved Node B), comprising of the PCell (Primary Cell) and optionally one or more SCell (Secondary Cell). A Secondary Cell Group is a group of serving cells associated with the SeNB (Secondary Evolved Node B), comprising of a SpCell (Special Cell) and optionally one or more SCell (Secondary Cell). A UE configured with dual connectivity generally means that the UE is configured to utilize radio resources that are provided by two distinct schedulers, and located in two eNBs (MeNB and SeNB) connected via a non-ideal backhaul over the X2 interface. Furthermore, C-plane messages are communicated via MeNB. Further details of dual connectivity can be found in 3GPP R2-145410.
In dual connectivity, a random access (RA) procedure may be performed upon SCG (Secondary Cell Group) addition, DL (downlink) data arrival, and UL (uplink) data arrival to achieve uplink synchronization. There are two different types of RA procedures: contention-based RA and contention-free RA.
A contention based RA procedure is shown in FIG. 5 and includes the following four steps:
1. Random Access Preamble is transmitted by UE on RACH (Random Access Channel), and is mapped to PRACH (Physical Random Access Channel);
2. Random Access Response is received from eNB on DL-SCH (Downlink Shared Channel), and is mapped to PDSCH (Physical Uplink Shared Channel);
3. Scheduled Transmission is transmitted by UE on UL-SCH (Uplink-Shared Channel), and is mapped to PUSCH (Physical Uplink Shared Channel); and
4. Contention Resolution is received from eNB on PDCCH (Physical Downlink Control Channel) or on DL-SCH, and is mapped to PDSCH.
A contention-free RA procedure is shown in FIG. 6 and includes the following three steps:
1. Random Access Preamble assignment is received from eNB (evolved Node B);
2. Random Access Preamble is transmitted by UE on UL-SCH (Uplink-Shared Channel), and is mapped to PUSCH; and
3. Random Access Response is received from eNB on DL-SCH (Downlink Shared Channel), and is mapped to PDSCH.
After transmitting a RA preamble, a UE shall monitor a PDCCH for RA response(s) from an eNB (i.e., a base station) in a RA response window, which starts at the subframe (or TTI (Transmission Time Interval)) that contains the end of the preamble transmission plus three subframes and has length ra-ResponseWindowSize subframes, as discussed in 3GPP TS 36.321 V12.3.0. If the UE does not receive a valid RA response from the eNB within the RA response window, the UE shall retransmit a RA preamble until the maximum number of retransmissions has been reached or a valid RA response is received. Thus, it might take more than one run to complete a RA procedure. Details of a RA procedure can be found in 3GPP R2-145410 and TS 36.321 V12.3.0.
In the current LTE RAT, a UE periodically transmits a sounding reference symbol/signal (SRS) for channel quality estimation to enable frequency-selective scheduling on the uplink. Thus, the resources for SRS transmissions cover wider bandwidth. Details of a UE sounding procedure can be found in 3GPP TS 36.213 V12.3.0.
Cells on the capacity layer may use beam forming, which is a signal processing technique used in antenna arrays for directional signal transmission or reception. This is achieved by combining elements in a phased array in such a way that signals at particular angles experience constructive interference while others experience destructive interference. Beam forming can be used at both the transmitting and receiving ends in order to achieve spatial selectivity. The improvement compared with omnidirectional reception/transmission is known as the receive/transmit gain.
The benefit of cochannel interference reduction and radio resource reuse makes beam forming attractive to a mobile communication system designer. U.S. Patent Publication No. 2010/0165914 generally discloses the concept of beam division multiple access (BDMA) based on the beam forming technique. In BDMA, a base station can communicate with a UE via a narrow beam to obtain the receive/transmit gain. Also, two UEs in different beams can share the same radio resources at the same time; and thus the capacity of a mobile communication system can increase greatly. To achieve that, the base station should know the beam in which a UE can communicate with the base station.
Furthermore, U.S. Pat. No. 7,184,492 generally discloses using beam forming antenna to coherently transmit an information signal to a receiver using two or more directional beams. In one embodiment, the phase and timing of the information signals carried by each directional beams are adjusted such that the signals arrive synchronously at the mobile terminal. Time synchronization may be obtained by delaying signals transmitted on selected directional beams to compensate for different propagation delays, or by preconditioning and filtering the signals using a channel coefficient matrix.
As discussed in 3GPP TS 36.300 V12.5.0, the frame structure in LTE is organized into radio frames and each radio frame (e.g., 10 ms), and is divided into ten subframes. As stated in 3GPP TS 36.300 V12.5.0, each subframe may include two slots as follows:
5 Physical Layer for E-UTRA
Frame structure Type 1 is illustrated in Figure 5.1-1 [which has been reproduced as FIG. 7 of the present application]. Each 10 ms radio frame is divided into ten equally sized sub-frames. Each sub-frame consists of two equally sized slots. For FDD, 10 subframes are available for downlink transmission and 10 subframes are available for uplink transmissions in each 10 ms interval. Uplink and downlink transmissions are separated in the frequency domain.
[Figure 5.1-1 has been reproduced as FIG. 7 of the present application]
Frame structure Type 2 is illustrated in Figure 5.1-2 [which has been reproduced as FIG. 8 of the present application]. Each 10 ms radio frame consists of two half-frames of 5 ms each. Each half-frame consists of eight slots of length 0.5 ms and three special fields: DwPTS, GP and UpPTS. The length of DwPTS and UpPTS is configurable subject to the total length of DwPTS, GP and UpPTS being equal to 1 ms. Both 5 ms and 10 ms switch-point periodicity are supported. Subframe 1 in all configurations and subframe 6 in configuration with 5 ms switch-point periodicity consist of DwPTS, GP and UpPTS. Subframe 6 in configuration with 10 ms switch-point periodicity consists of DwPTS only. All other subframes consist of two equally sized slots.
[Figure 5.1-2 has been reproduced as FIG. 8 of the present application]
[Table 5.1-1 “Uplink-downlink allocations” has been reproduced as FIG. 9 of the present application]
Each downlink slot includes NsymbDL OFDM symbols as shown in Figure 6.2.2-1 (which has been reproduced as FIG. 10 of the present application) and in Table 6.2.3-1 (which has been reproduced as FIG. 11 of the present application) of 3GPP TS 36.211 V12.5.0. Figure 6.2.2-1 of 3GPP TS 36.211 V12.5.0 has been reproduced as FIG. 10 of the present application. Table 6.2.3-1 “Physical resource blocks parameters” of 3GPP TS 36.211 V12.5.0 has been reproduced as FIG. 11 of the present application.
A TDD (Time Division Duplex) optimized physical subframe structure for a UDN (Ultra Dense Network) system proposed by METIS Deliverable D2.4 “Proposed solutions for new radio access” is illustrated in FIG. 12 while following the main design principles listed below:
Data part in one subframe contains data symbols for either transmission or reception. Demodulation Reference Signal (DMRS) symbols, which are used to estimate the channel and its covariance matrix, could be located, for example, in the first OFDM (Orthogonal Frequency-Division Multiplexing) symbol in the dynamic data part and could be precoded with the same vector or matrix as data.
Short subframe lengths, such as e.g. 0.25 ms on cmW frequencies when assuming 60 kHz SC spacing, are feasible. By following the principles of harmonized OFDM concept, the frame numerology is further scaled when moving to mmW, leading to even shorter frame length (e.g., in the order of 50 μs).
In frequency direction, the spectrum could be divided to separate allocable frequency resources.
The bi-directional control part of the subframe allows the devices in the network to both receive and send control signals, such as scheduling requests (SRs) and scheduling grants (SGs), in every subframe. In addition to the scheduling related control information, the control part may also contain reference signals (RS) and synchronization signals used for cell detection and selection, scheduling in frequency domain, precoder selection, and channel estimation.
To find beam(s) in which a UE can communicate with a base station, it is proposed in US Patent Publication No. 2010/0165914 that the UE transmits its position and speed to the base station, and the base station then determines the direction of a downlink beam for the UE according to the received position and speed. In this way, however, the base station may not able to determine the UE's beams accurately, due to the very complicated propagation environment in mobile cellular systems. In addition, typically not all UEs in a cell are equipped with positioning capability (e.g., low end devices). As a result, the benefit of BDMA (Beam Division Multiple Access) cannot be enjoyed if there are many low end devices in a cell. Other ways for a base station to determine UE's beams could and should be considered to improve this drawback.
A potential beam pattern applied by a base station for transmission and/or reception in a cell could be fixed as shown in FIG. 13. That is the number of beams and the beam-widths of beams in a cell are fixed, while the beam-widths of beams in different directions could be different. Due to multiple propagation paths or overlapping between two neighboring beams, it is likely that multiple beams would be used by a UE for communicating with the base station. In this situation, the base station needs to determine the beam set used by a UE (e.g., by monitoring an uplink signal transmitted from the UE).
Since a random access (RA) procedure needs to be performed by a UE before data can be transferred via a cell, it would be beneficial for the base station to determine the initial beam set of a UE during the RA procedure, especially if a dedicated RA preamble is used. For example, the beam set could be determined according to the beam(s) via which the dedicated RA preamble(s) is (are) received from the UE.
Considering the enlarged number of antennas with wider bandwidth, it is quite challenging in terms of overall cost and power consumption to implement beam forming in a cell with one transceiver per antenna element. As a result, the maximum number of beams which could be generated by a cell at one time could be less than the total number of beams covered by a cell. Thus, it may take several times for the cell to scan all beams of the cell. In this situation, the base station would miss a dedicated RA preamble transmitted from a UE if none of the beams points to the direction of the UE when the RA preamble is transmitted. As a result, several runs of random access may be required to successfully complete a RA procedure, which would cause latency to the subsequent data transfer via the cell. In addition, resource sharing between the concerned UE and other UEs in the cell would be delayed. This is undesirable.
To reduce the latency, a potential solution is for a UE to transmit multiple RA preambles in a short period of time before it starts monitoring a PDCCH for RA response(s) from the base station. The base station would then be allowed to complete scanning all beams of the cell so as to receive at least one RA preamble from the UE. With this solution, a RA procedure could be successfully completed without too much latency. FIG. 14 shows an example of this solution according to one exemplary embodiment.
In FIG. 14, it is assumed the UE is located in beams X and Y. The base station monitors preambles at T1, T2, and T3 for receiving preambles via different beams of the cell. In this example, multiple beams could be monitored at each time. The preamble transmitted by the UE is received via beams X and Y at T2. Thus, the beam set of the UE is {X, Y}. It is possible that preambles transmitted by the UE could be received at different times. On the other hand, the base station does not transmit any RA response to the UE until all the multiple beams of the cell has been monitored. In other words, the base station transmits a RA response to the UE after all beams of the cell has been monitored if there is any RA preamble received.
Preferably, the base station could determine a beam set of the UE according to the beam(s) via which RA preamble(s) is (are) received from the UE. After the initial beam set of a UE has been determined, the base station needs to continue tracking the UE and update the beam set due to UE mobility. It seems possible for the base station to track the beam set of a UE based on periodic SRS-like reference signal (RS) transmissions from the UE, wherein it could be sufficient for the SRS-like RS to cover narrower bandwidth. Then, the beam set could be updated according to the beam(s) via which the RS(s) is (are) received from the UE. More precisely, a potential solution is for the UE to transmit multiple RSs in each period, which would allow the base station to complete scanning all beams of the cell in a short time so as to receive at least one RS from the UE for updating the beam set of the UE. FIG. 15 illustrates an example of this solution according to one exemplary embodiment.
In FIG. 15, a UE periodically transmits RSs for beam set update after an initial beam set of the UE has been determined by a base station. During the first period, the base station monitors RS at T1, T2, and T3 via different beams of the cell and RS is received via beams X and Y at T2. The beam set of the UE is updated to {X, Y}. Due to UE mobility, RS is received via beam Z alone at T6 during the second period. As a result, the new beam set is {Z}. In this example, multiple beams are monitored at each time. It is also possible that RSs transmitted by the UE could be received at different times.
In general, there could be two different ways for the base station to control beam set tracking, including a distributed way and a centralized way. In the distributed way, each UE would be tracked individually at UE specific times and is allocated with RS resources, wherein the RS resources define periodic resources for RS transmissions and there are multiple occasions with resources for transmissions of multiple RSs by the UE in each RS period. In one embodiment, an occasion refers to a time unit (e.g., a symbol, a time slot, or a subframe).
In the centralized way, all UEs (which need to be tracked in the cell) are tracked at common occasions so that the base station only needs to monitor those occasions to receive RSs transmitted by all UEs. In one embodiment, all UEs share one RS period. In another embodiment, UEs may have different RS periods, while timings of all RS periods are synchronized. For example, there is a nominal RS period and a RS period of each UE is a multiple of the nominal RS period. FIG. 16 shows examples of these two options. For Option 1, all UEs share one RS period and the base station needs to monitor RSs from all UEs in each RS period (i.e., the tracking period=the RS period), while the base station needs to monitor RSs from UEs in each nominal RS period (i.e., the tracking period=the nominal RS period X 1) for Option 2 (i.e., UE specific RS period). In one embodiment, each occasion of a RS period is shared by all UEs which need to be tracked (in case there are sufficient RS resources on each occasion for all UEs). In another embodiment, different occasions of the RS period are occupied by different UEs.
If digital beam-former is used for implementing a cell, there would be no problem to have one transceiver per antenna element i.e. all beams of the cell can be generated at one time. Thus, each UE would only need to transmit a single RS for base station to determine the beam set of the UE. Similar methods for beam tracking described above for a cell with analog beam-former are also applicable to a cell with digital beam-former. In this situation (i.e., a cell with digital beam-former), the base station would only need to allocate RS resources to each UE for one single RS transmission on one occasion in each RS period for beam tracking if digital beam-former is used. It is possible that all UEs share one RS period or UEs may have different RS periods. In one embodiment, each occasion of a RS period is shared by all UEs which need to be tracked. In another embodiment, different occasions of the RS period are occupied by different UEs.
A TDD optimized physical subframe structure for a UDN system is proposed by METIS Deliverable D2.4 “Proposed solutions for new radio access”. In general, there are one uplink control part, one downlink control part, and one data part as shown in FIG. 12. To support BDMA, an uplink control part may need to contain PUCCH (Physical Uplink Control Channel) signaling for HARQ ACK/NACK (Hybrid Automatic Repeat Request Acknowledgement/Negative Acknowledgement) and RS for UE beam set detection. The UE would send a HARQ ACK/NACK in response to a downlink transmission from a base station. Since PUCCH signaling for HARQ ACK/NACK and RS for UE beam set detection may be transmitted by different UEs and received by the base station via different beams, it is more flexible in term of scheduling to have at least two symbols in the uplink control part: (1) one symbol contains RS resources for UE beam set detection and (2) another symbol not contain any RS resource for UE beam set detection. In one embodiment, the symbol which contains RS resources for UE beam set detection may also contain resources for HARQ ACK/NACK signaling. This embodiment would be feasible if the beam(s) used by the base station to receive PUCCH signaling for HARQ ACK/NACK is the same as the beam(s) used for monitoring RS for UE beam set detection. Otherwise, the base station may miss the PUCCH signaling for HARQ ACK/NACK, which would degrade the transmission performance.
FIG. 17 is a flow chart 1700, in accordance with one exemplary embodiment, outlining a method for preamble transmissions by a UE in a cell of a wireless communication system, wherein there are multiple beams in the cell. In step 1705, the UE initiates a random access (RA) procedure. In step 1710, the UE transmits multiple RA preambles to a base station of the cell at different occasions for the base station to determine a beam set of the UE.
In step 1715, the UE starts monitoring a Physical Downlink Control Channel (PDCCH) for RA response reception from the base station after finishing transmissions of the multiple RA preambles. In one embodiment, the UE monitors the PDCCH for RA response reception in a RA response window. Furthermore, the RA response window could start at a subframe that contains an end of a transmission of the last RA preamble of the multiple RA preambles plus a number of subframes and has a length configured to the UE. More specifically, the RA response window could start at a subframe that contains the end of the transmission of the last RA preamble transmission plus three (3) subframes. Furthermore, the UE could receive one RA response for the UE within the RA response window.
In one embodiment, the UE could decode each RA response individually without combining multiple RA responses. In another embodiment, the UE could be within normal coverage of the base station, such as the received signal quality of the UE from the base station is above a threshold, so that the UE could decode each RA response individually without combining multiple RA responses.
Referring back to FIGS. 3 and 4, in one embodiment from the perspective of a UE, the device 300 includes a program code 312 stored in memory 310 of the transmitter. The CPU 308 could execute program code 312 (i) to initiate a RA procedure, (ii) to transmit multiple RA preambles to a base station of the cell at different occasions for the base station to determine a beam set of the UE, and (iii) to start monitoring a Physical Downlink Control Channel (PDCCH) for RA response reception from the base station after finishing transmissions of the multiple RA preambles. In addition, the CPU 308 can execute the program code 312 to perform all of the above-described actions and steps or others described herein.
FIG. 18 is a flow chart 1800 from the perspective of a base station in accordance with one exemplary embodiment. In general, the flow chart 1800 outlines a method for beam finding in a cell of a wireless communication system, wherein there are multiple beams in the cell. In step 1805, a base station of the cell monitors RA preamble(s) via different beams at different occasions during a RA procedure. In step 1810, the base station receives at least a RA preamble from a UE. In step 1815, the base station determines a beam set of the UE according to the beam(s) via which the RA preamble(s) is (are) received.
In step 1820, the base station transmits a RA response to the UE after all the multiple beams of the cell have been monitored. In one embodiment, the base station transmits only one RA response to the UE in response to receptions of multiple RS preambles from the UE during the RA procedure. Furthermore, multiple beams are monitored at each occasion. In addition, an occasion refers to a time unit (e.g., a symbol, a time slot, or a subframe).
In one embodiment, the RA preamble is dedicated to the UE. In addition, the RA preamble being dedicated to the UE could mean the RA preamble of the UE is distinguishable from RA preambles of other UEs in the cell in at least one of following domains: time domain, frequency domain, and sequence domain.
Referring back to FIGS. 3 and 4, in one embodiment from the perspective of a base station, the device 300 includes a program code 312 stored in memory 310 of the transmitter. The CPU 308 could execute program code 312 (i) to monitor RA preamble(s) via different beams at different occasions during a RA procedure, (ii) to receive at least a RA preamble from a UE, and (iii) to determine a beam set of the UE according to the beam(s) via which the RA preamble(s) is (are) received. In addition, the CPU 308 could execute program code 312 to transmit a RA response to the UE after all the multiple beams of the cell have been monitored. Furthermore, the CPU 308 can execute the program code 312 to perform all of the above-described actions and steps or others described herein.
FIG. 19 is a flow chart 1900, in accordance with one exemplary embodiment, outlining a method for determining a beam set used by a UE in a cell of a wireless communication system, wherein there are multiple beams in the cell. In general, the method outlined in the flow chart 1900 could be applied by a base station in distributed and centralized settings.
In step 1905, the UE is allocated with reference signal (RS) resources on the cell, wherein the RS resources define periodic resources for RS transmissions, and there are multiple occasions with resources for transmissions of multiple RSs by the UE in each RS period. In step 1910, a base station of the cell uses at least one beam to receive a RS transmitted from the UE on each occasion in a RS period. In one embodiment, the base station uses different sets of beams to receive RSs transmitted from the UE on different occasions in the RS period. Furthermore, the total beams could be used to receive RSs transmitted from the UE in the RS period cover all beams of the cell.
In one embodiment, the multiple occasions could be UE specific. In an alternative embodiment, the multiple occasions could be shared by UEs which need to be tracked.
Referring back to FIGS. 3 and 4, the device 300 includes a program code 312 stored in memory 310 of the transmitter. The CPU 308 could execute program code 312 (i) to enable the UE to be allocated with RS resources on the cell, wherein the RS resources define periodic resources for RS transmissions, and there are multiple occasions with resources for transmissions of multiple RSs by the UE in each RS period, and (ii) to enable a base station to use at least one beam to receive a RS transmitted from the UE on each occasion in a RS period. In addition, the CPU 308 can execute the program code 312 to perform all of the above-described actions and steps or others described herein.
FIG. 20 is a flow chart 2000, in accordance with one exemplary embodiment, outlining a method for determining beam sets used by UEs in a cell of a wireless communication system, wherein each UE has its own beam set and there are multiple beams in the cell. In general, the method outlined in the flow chart 2000 could be applied by a base station in a centralized setting and to the same RS period for all UEs.
In step 2005, each UE is allocated with reference signal (RS) resources on the cell, wherein the RS resources define periodic resources for RS transmissions, there are multiple occasions with resources for transmissions of multiple RSs by each UE in each RS period, and one RS period is shared by UEs which need to be tracked. In step 2010, a base station of the cell uses at least one beam to receive RSs transmitted from UEs on each occasion in the RS period, wherein the total beams used to receive the RSs transmitted from UEs in the RS period cover all beams of the cell.
In one embodiment, the base station determines the beam set used by the UE according to the beam(s) via which RS(s) is (are) received from the UE. In another embodiment, the base station could transmit a message to allocate the RS resources to the UE (for single connectivity). In an alternative embodiment, a second base station of a second cell serving the UE could transmit a message to allocate the RS resources to the UE (for dual connectivity).
In one further embodiment, the beam set used by a UE contains at least one beam. Furthermore, an occasion refers to a time unit (e.g., a symbol, a time slot, or a subframe).
Referring back to FIGS. 3 and 4, the device 300 includes a program code 312 stored in memory 310 of the transmitter. The CPU 308 could execute program code 312 (i) to enable each UE to be allocated with RS resources on the cell, wherein the RS resources define periodic resources for RS transmissions, there are multiple occasions with resources for transmissions of multiple RSs by each UE in each RS period, and one RS period is shared by UEs which need to be tracked, and (ii) to enable a base station of the cell to use at least one beam to receive a RS transmitted from the UE on each occasion in a RS period. In addition, the CPU 308 can execute the program code 312 to perform all of the above-described actions and steps or others described herein.
FIG. 21 is a flow chart 2100, in accordance with one exemplary embodiment, outlining a method for determining beam sets used by UEs in a cell from the perspective of a UE. In general, the method outlined in the flow chart 2100 could be applied by a base station in a centralized setting and to a UE-specific RS period.
In step 2105, each UE is allocated with reference signal (RS) resources on the cell, wherein the RS resources define periodic resources for RS transmissions, there are multiple occasions with resources for transmissions of multiple RSs by each UE in each RS period, and a RS period of each UE is a multiple of a nominal RS period. In step 2110, a base station of the cell uses at least one beam to receive RSs transmitted from UEs on each occasion in a tracking period, wherein the total beams used to receive the RSs transmitted from UEs in the tracking period cover all beams of the cell. In one embodiment, the tracking period could be determined according to the RS periods of UEs which need to be tracked. Furthermore, the tracking period could be a multiple of the nominal RS period. In addition, the tracking period could be equal to the nominal RS period.
In step 2115, the base station determines the beam set used by the UE according to the beam(s) via which RS(s) is (are) received from the UE. In one embodiment, the base station could transmit a message to allocate the RS resources to the UE (for single connectivity). In an alternative embodiment, a second base station of a second cell serving the UE could transmit a message to allocate the RS resources to the UE (for dual connectivity).
In one embodiment, the beam set used by a UE contains at least one beam. Furthermore, an occasion refers to a time unit (e.g., a symbol, a time slot, or a subframe).
Referring back to FIGS. 3 and 4, the device 300 includes a program code 312 stored in memory 310 of the transmitter. The CPU 308 could execute program code 312 (i) to enable each UE to be allocated with RS resources on the cell, wherein the RS resources define periodic resources for RS transmissions, there are multiple occasions with resources for transmissions of multiple RSs by each UE in each RS period, and a RS period of each UE is a multiple of a nominal RS period, (ii) to enable a base station of the cell to use at least one beam to receive RSs transmitted from UEs on each occasion in a tracking period, wherein the total beams used to receive the RSs transmitted from UEs in the tracking period cover all beams of the cell, and (iii) to enable the base station to determine the beam set used by the UE according to the beam(s) via which RS(s) is (are) received from the UE. In addition, the CPU 308 can execute the program code 312 to perform all of the above-described actions and steps or others described herein.
FIG. 22 is a flow chart 2200, in accordance with one exemplary embodiment, outlining a method for RS transmissions by a UE in a cell of a wireless system. In step 2205, the UE receives a message indicating reference signal (RS) resources on a cell, wherein the RS resources define periodic resources for RS transmissions, and there are multiple occasions with resources for transmissions of multiple RSs by the UE in each RS period. In step 2110, the UE transmits multiple RSs in each RS period to a base station of the cell.
In one embodiment, the UE could receive the message from the base station (for single connectivity). Alternatively, the UE could receive the message from a second base station of a second cell serving the UE (for dual connectivity). In addition, there could be multiple beams in the cell.
In one embodiment, an occasion could refer to a time unit in FDD (Frequency Division Duplex) mode (e.g., a symbol, a time slot, or a subframe). Alternatively, an occasion could refer to a time unit in TDD (Time Division Duplex) mode (e.g., a symbol in a normal subframe, a time slot, or a subframe). Furthermore, the multiple occasions could be contiguous, and each occasion of a RS period could be shared by all UEs which need to be tracked. In addition, different occasions of the RS period could be occupied by different UEs.
In one embodiment, the RSs could be dedicated to a particular UE, which means the RSs of the particular UE are distinguishable from RSs of other UEs in the cell in at least one of following domains: time domain, frequency domain, and/or sequence domain.
Referring back to FIGS. 3 and 4, in one embodiment from the perspective of a UE, the device 300 includes a program code 312 stored in memory 310 of the transmitter. The CPU 308 could execute program code 312 (i) to receive a message indicating reference signal (RS) resources on a cell, wherein the RS resources define periodic resources for RS transmissions, and there are multiple occasions with resources for transmissions of multiple RSs by the UE in each RS period, and (ii) to transmit multiple RSs in each RS period to a base station of the cell. In addition, the CPU 308 can execute the program code 312 to perform all of the above-described actions and steps or others described herein.
FIG. 23 is a flow chart 2300, in accordance with one exemplary embodiment, outlining a method for determining beam sets used by UEs in a cell of a wireless system, wherein each UE has its own beam set and there are multiple beams in the cell. In general, the method outlined in the flow chart 2300 could be applied by a base station in a centralized setting and to the same RS period for all UEs.
In step 2305, each UE is allocated with periodic RS resources on the cell for RS transmissions, wherein UEs which need to be tracked in the cell share one RS period. In step 2310, a base station of the cell uses all beams of the cell to receive RSs transmitted from UEs on each occasion with RS resources in each RS period. In one embodiment, the RS resources in each RS period for UEs which need to be tracked are located in one subframe. Furthermore, there is at least one occasion with RS resources in each RS period.
In step 2315, the base station determines the beam set used by the UE according to the beam(s) via which RS(s) is (are) received from the UE. In one embodiment, the base station could transmit a message to allocate the RS resources to the UE (for single connectivity). Furthermore, a second base station of a second cell serving the UE could transmit a message to allocate the RS resources to the UE (for dual connectivity).
In one embodiment, the beam set used by a UE contains at least one beam. In addition, the RSs are dedicated to the UE, which means the RSs of the UE are distinguishable from RSs of other UEs in the cell in at least one of following domains: time domain, frequency domain, and sequence domain.
In one embodiment, an occasion refers to a time unit e.g. a symbol, a time slot, or a subframe. Furthermore, each occasion of a RS period could be shared by all UEs which need to be tracked. In addition, different occasions of the RS period could be occupied by different UEs.
Referring back to FIGS. 3 and 4, in one embodiment from the perspective of a base station, the device 300 includes a program code 312 stored in memory 310 of the transmitter. The CPU 308 could execute program code 312 (i) to allocate each UE with periodic RS resources on the cell for RS transmissions, wherein UEs which need to be tracked in the cell share one RS period, and (ii) to enable a base station of the cell to use all beams of the cell to receive RSs transmitted from UEs on each occasion with RS resources in each RS period.
In one embodiment, the CPU 308 could further execute program code 312 to enable the base station to determine the beam set used by the UE according to the beam(s) via which RS(s) is (are) received from the UE. In addition, the CPU 308 can execute the program code 312 to perform all of the above-described actions and steps or others described herein.
FIG. 24 is a flow chart 2400, in accordance with one exemplary embodiment, outlining a method for determining beam sets used by UEs in a cell of a wireless system, wherein each UE has its own beam set and there are multiple beams in the cell. In general, the method outlined in the flow chart 2400 could be applied by a base station in a centralized setting and to a UE-specific RS period.
In step 2405, each UE is allocated with periodic RS resources on the cell for RS transmissions, wherein a RS period of the UE is a multiple of a nominal RS period. In step 2410, a base station of the cell uses all beams of the cell to receive RSs transmitted from UEs on each occasion with RS resources in each tracking period.
In one embodiment, the RS resources in each tracking period for UEs which need to be tracked are located in one subframe. Furthermore, there is at least one occasion with RS resources in each tracking period.
In one embodiment, the tracking period is determined according to the RS periods of UEs which need to be tracked in the cell. Furthermore, the tracking period is a multiple of the nominal RS period. In addition, the tracking period is equal to the nominal RS period.
In step 2415, the base station determines the beam set used by the UE according to the beam(s) via which RS(s) is (are) received from the UE. In one embodiment, the base station could transmit a message to allocate the RS resources to the UE (for single connectivity). Furthermore, a second base station of a second cell serving the UE could transmit a message to allocate the RS resources to the UE (for dual connectivity).
Referring back to FIGS. 3 and 4, in one embodiment from the perspective of a base station, the device 300 includes a program code 312 stored in memory 310 of the transmitter. The CPU 308 could execute program code 312 (i) to allocate each UE with periodic RS resources on the cell for RS transmissions, wherein a RS period of the UE is a multiple of a nominal RS period, and (ii) to enable a base station of the cell to use all beams of the cell to receive RSs transmitted from UEs on each occasion with RS resources in each tracking period.
FIG. 25 is a flow chart 2500, in accordance with one exemplary embodiment, outlining a method for defining a subframe structure for beam detection. In step 2505, a cell communicates with UEs in the cell via downlink transmissions and uplink receptions, wherein the downlink transmissions and uplink receptions are organized into radio frames. In step 2510, a radio frame is constructed with multiple subframes, wherein a subframe in the radio frame includes at least an uplink control part, and the uplink control part includes at least: (1) a first symbol, which is allocated with resources for the UEs to transmit reference signals for the cell to determine beam sets of the UEs, and (2) a second symbol, which is not allocated with resources for the UEs to transmit the reference signals for the cell to determine beam set of the UEs.
In one embodiment, a first symbol is allocated with resources for HARQ ACK/NACK (Hybrid Automatic Repeat Request Acknowledgement/Negative Acknowledgement) signaling in step 2515. Furthermore, a second symbol is allocated with resources for HARQ ACK/NACK signaling in step 2520.
Referring back to FIGS. 3 and 4, in one embodiment from the perspective of a cell, the device 300 includes a program code 312 stored in memory 310 of the transmitter. The CPU 308 could execute program code 312 (i) to enable a cell to communicate with UEs via downlink transmissions and uplink receptions, wherein the downlink transmissions and uplink receptions are organized into radio frames, and (ii) to construct a radio frame with multiple subframes, wherein a subframe in the radio frame includes at least an uplink control part, and the uplink control part includes at least: (1) a first symbol, which is allocated with resources for the UEs to transmit reference signals for the cell to determine beam sets of the UEs, and (2) a second symbol, which is not allocated with resources for the UEs to transmit the reference signals for the cell to determine beam sets of the UEs.
In one embodiment, the CPU 308 could further execute program code 312 to allocate the first symbol and the second symbol with resources for HARQ ACK/NACK signaling. In addition, the CPU 308 can execute the program code 312 to perform all of the above-described actions and steps or others described herein.
FIG. 26 is a flow chart 2600, in accordance with one exemplary embodiment, outlining a method for defining a subframe structure for beam detection. In step 2605, a UE communicates with a cell via uplink transmissions and downlink receptions, wherein the uplink transmissions and downlink receptions are organized into radio frames. In step 2610, a radio frame is constructed with multiple subframes, wherein a subframe in the radio frame includes at least an uplink control part, and the uplink control part includes at least: (1) a first symbol, which is allocated with resources for the UE to transmit reference signals for the cell to determine a beam set of the UE, and (2) a second symbol, which is not allocated with resources for the UE to transmit the reference signals for the cell to determine the beam set of the UE.
In one embodiment, a first symbol is allocated with resources for HARQ ACK/NACK signaling in step 2615. Furthermore, a second symbol is allocated with resources for HARQ ACK/NACK signaling in step 2520.
Referring back to FIGS. 3 and 4, in one embodiment from the perspective of a UE, the device 300 includes a program code 312 stored in memory 310 of the transmitter. The CPU 308 could execute program code 312 (i) to enable a UE to communicate with a cell via uplink transmissions and downlink receptions, wherein the uplink transmissions and downlink receptions are organized into radio frames, and (ii) to construct a radio frame with multiple subframes, wherein a subframe in the radio frame includes at least an uplink control part, and the uplink control part includes at least: (1) a first symbol, which is allocated with resources for the UE to transmit reference signals for the cell to determine a beam set of the UE, and (2) a second symbol, which is not allocated with resources for the UE to transmit the reference signals for the cell to determine the beam set of the UE.
With respect to the methods outlined in FIGS. 25 and 26, in one embodiment, the subframe in the radio frame could contain a downlink control part and/or a data part. Furthermore, the subframe structure could be used in a TDD (Time Division Duplex) mode.
In one embodiment, the downlink transmissions and uplink receptions relevant to the UE could be performed by the cell on multiple beams in a beam set of the UE. Furthermore, a total number of beams in the cell could be fixed. In addition, the direction and/or the width of each beam in the cell could be fixed.
In one embodiment, there is a period associated with transmissions of the reference signals and there are multiple resources for reference signal transmissions at different occasions (or timings) in each period.
1. A method for determining a beam set used by a user equipment (UE) in a cell of a wireless communication system, wherein there are multiple beams in the cell, comprising:
a base station of the cell determines an initial beam set of the UE via a contention based random access procedure;
the base station of the cell transmits a message indicating reference signal (RS) resources on a cell to the UE after the initial beam set of the UE has been determined,
wherein the RS resources define periodic resources for RS transmissions, and
wherein there are multiple contiguous symbols with resources for transmissions of multiple RSs by the UE in each RS period, and a length of each RS period is greater than a length of the multiple contiguous symbols with resources for transmissions of multiple RSs by the UE in each RS period; and
the base station of the cell uses at least one beam to receive a RS transmitted from the UE on each symbol of the multiple contiguous symbols in each RS period.
the base station uses different sets of beams to receive RSs transmitted from the UE on different symbols in the RS period.
3. The method of claim 1, wherein the total beams used to receive RSs transmitted from the UE in the RS period cover all beams of the cell.
4. The method of claim 1, wherein the multiple contiguous symbols with resources for RS transmissions are UE specific.
5. The method of claim 1, wherein the RSs are dedicated to the UE.
6. The method of claim 5, wherein the RSs dedicated to the UE means the RSs of the UE are distinguishable from RSs of other UEs in the cell in at least one of following domains: time domain, frequency domain, and sequence domain.
7. A method for reference signal (RS) transmissions by a user equipment (UE) in a cell of a wireless communication system, comprising:
the UE performs a contention based random access procedure for a base station of the cell to determine an initial beam set of the UE;
the UE receives a message indicating RS resources on a cell after the initial beam set of the UE has been determined by the base station of the cell,
the UE transmits multiple RSs on the multiple contiguous symbols in each RS period to the base station of the cell.
8. The method of claim 7, wherein the multiple contiguous symbols with resources for RS transmissions are UE specific.
9. The method of claim 7, wherein the RSs are dedicated to the UE.
10. method of claim 9, wherein the RSs dedicated to the UE means the RSs of the UE are distinguishable from RSs of other UEs in the cell in at least one of following domains: time domain, frequency domain, and sequence domain.
wherein the processor is configured to execute a program code stored in the memory to: perform a contention based random access procedure for a base station of the cell to determine an initial beam set of the UE; receive a message indicating reference signal (RS) resources on a cell after the initial beam set of the UE has been determined by the base station of the cell, wherein the RS resources define periodic resources for RS transmissions, and wherein there are multiple contiguous symbols with resources for transmissions of multiple RSs by the UE in each RS period, and a length of each RS period is greater than a length of the multiple contiguous symbols with resources for transmissions of multiple RSs by the UE in each RS period; and transmit multiple RSs on the multiple contiguous symbols in each RS period to the base station of the cell.
12. The UE of claim 11, wherein the multiple contiguous symbols with resources for RS transmissions are UE specific.
13. The UE of claim 11, wherein the RSs are dedicated to the UE.
14. The UE of claim 13, wherein the RSs dedicated to the UE means the RSs of the UE are distinguishable from RSs of other UEs in the cell in at least one of following domains: time domain, frequency domain, and sequence domain.
15. The method of claim 1, wherein there are at least 3 periods of RS resources for RS transmissions.
16. The method of claim 7, wherein there are at least 3 periods of RS resources for RS transmissions.
17. The UE of claim 11, wherein there are at least 3 periods of RS resources for RS transmissions.
20130337822 December 19, 2013 Rubin
20140185481 July 3, 2014 Seol
20140254515 September 11, 2014 Kim
European Search Report from corresponding EP Application No. 18152087.5, dated Apr. 11, 2018.
Patent number: 10477554
Patent Publication Number: 20180146468
Inventor: Richard Lee-Chee Kuo (Taipei)
Application Number: 15/858,926
International Classification: H04B 7/06 (20060101); H04W 72/04 (20090101); H04W 74/08 (20090101); H04W 74/00 (20090101); H04W 88/02 (20090101); H04W 88/08 (20090101);