Spatial multiplexing for random access channel (RACH) preamble reception

Abstract

A network node establishes a receive antenna pattern for receiving uplink signals from a terminal where the receive antenna pattern is based on a transmission antenna pattern including transmission antenna beams having indices used by the terminal to determine time and frequency resources for transmitting the uplink signals. The uplink signals may include Random Access Channel (RACH) preamble transmissions based on a Synchronization System Block (SSB) index of an SSB of a transmission antenna beam selected by the terminal. Interference resulting from RACH preamble transmissions at the same RACH Occasion (RO) is mitigated. By taking advantage of spatial diversity achieved with narrower receiver beam widths, RACH preambles associated with different SSBs and transmitted by different terminals using the same communication resources can be received.

Description

SPATIAL MULTIPLEXING FOR RANDOM ACCESS CHANNEL (RACH) PREAMBLE RECEPTIONCLAIM OF PRIORITY

[0001] The present application claims priority to Provisional Application No. 63 / 636,533, entitled “Spatial Multiplexing of P-RACH using Time Domain Beamforming,” filed April 19, 2024, assigned to the assignee hereof and hereby expressly incorporated by reference in its entirety.FIELD

[0002] This invention generally relates to wireless communications and more particularly to spatial multiplexing for random access channel (RACH) preamble reception.BACKGROUND

[0003] Many wireless communication systems utilize initial access procedures to allow a terminal (e.g., mobile device) to access a network through a network node (e.g., gNB). Revisions of the Third Generation Partnership Project (3GPP) communication specification, for example, define Random Access Channel (RACH) procedures where a terminal first obtains downlink synchronization with the network node and obtains RACH information. Based on the RACH information, the terminal transmits a RACH preamble to the network node during a RACH Occasion (RO). The set of time and frequency domain resources dedicated by the gNb for the RO is determined by RACH information received in a broadcast message, and is governed by 3GPP communication tables specifying RACH configuration indices and mappings.SUMMARY

[0004] A network node establishes a receive antenna pattern for receiving uplink signals from a terminal where the receive antenna pattern is based on a transmissionantenna pattern including transmission antenna beams having indices used by the terminal to determine time and frequency resources for transmitting the uplink signals. The uplink signals may include Random Access Channel (RACH) preamble transmissions based on a Synchronization System Block (SSB) index of an SSB of a transmission antenna beam selected by the terminal. Interference resulting from RACH preamble transmissions at the same RACH Occasion (RO) is mitigated. By taking advantage of spatial diversity achieved with narrower receiver beam widths, RACH preambles associated with different SSBs and transmitted by different terminals using the same communication resources can be received.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] FIG. 1 A is a block diagram of a communication system for an example of receive antenna management for Random Access Channel (RACH) preamble reception using spatial diversity.

[0006] FIG. 1 B is an illustration of an example of a portion of a transmission antenna radiation pattern and a portion of a reception antenna radiation pattern configured to minimize interference between RACH transmissions received at the network node.

[0007] FIG. 1 C is an illustration of an example in conventional system of the relationship between a transmission antenna radiation pattern and reception antenna radiation pattern.

[0008] FIG. 2 is a block diagram of an example of a base station suitable for use as the network node.

[0009] FIG. 3 is a block diagram of an example of a user equipment (UE) device suitable for use as the terminal.

[0010] FIG. 4 is a flow chart of an example of a method of spatially multiplexing RACH preamble reception.DETAILED DESCRIPTION

[0011] As discussed above, terminals (UEs) initiate connection to a network by sending a preamble signal over RACH to a network node (base station). A terminal receives and measures reference signals transmitted via transmit antenna beams and select a best transmit antenna beam for communication. Based at least partially on information within broadcast message, such an SIB1 message, the terminal determines the time-frequency resources including an RO for transmitting the RACH preamble associated with the selected transmit beam. In conventional systems, the receive antenna pattern typically includes wider receive antenna beams than the transmit beams of the transmit antenna pattern. In conventional systems, therefore, a single receive antenna beam may be used for the reception of two RACH preamble transmissions from two different terminals associated with different transmit beams in the same RO using the same time-frequency resources. In other words, the relatively wider receive antenna beam may form the portion of the receive antenna pattern that is directed to the two terminals even though each terminal selected a different transmit antenna beam for communication. As a result, the two RACH preamble transmissions may suffer from interference where one or both signals may not be successfully received at the network node. For the examples described herein, however, the receive antenna beams are selected to coincide with the transmit antenna beams at least for receiving RACH preamble transmissions associated with different transmit antenna beams but transmitted using the same time-frequency resources.

[0012] A network node is any apparatus, equipment, device, or combination of devices, on the network side of the communication system that is connected to the communication network or is part of communication network. Some examples of a network node include a base station, a node B, an E-UTRA Node B, Evolved Node B, eNodeB, eNB, a New Generation eNB (ng-eNB), a gNodeB (also known as a gNB) in new radio (NR) technology, a macro station, pico station, and a femto station. The network node may form, or be a part of, the radio access network (RAN) that provides a connection between the core network and terminal communication devices. A RAN may be organized into three functional blocks including a Radio Unit (RU), a DistributedUnit (DU) and a Centralized Unit (CU). The RU transmits, receives, amplifies, and digitizes radio frequency signals and typically located near, or integrated into, the antenna. The DU and CU perform computations and / or processing to send and receive digitalized radio signals to and from the core network. The DU is typically located at or near the RU and the CU may be closer to the core network. The infrastructure or connection between the RU and the DU is often referred to as fronthaul and the infrastructure or connection between the DU and the CU is often referred to as a midhaul. The communication node, therefore, may perform the functions of one or more of the RU, DU and / or CU depending on the particular implementation.

[0013] A terminal communication device (terminal), such as a remote terminal and a relay terminal, is a communication device on the terminal side of the communication system and is sometimes referred to as user equipment (UE), a UE device, a terminal device, wireless mobile device, wireless communication device and other terms. Some examples of a terminal communication device include a mobile phone, a smart phone, a personal digital assistant (PDA), tablet, and laptop computer. In some situations, the terminal communication device is a machine type communication (MTC) communication device or Internet-of-Things (IOT) device. In addition, the terminal communication device may be, or may be a part of, a wearable device or a vehicle where the vehicle may be terrestrial vehicle, watercraft, or aircraft (including unmanned aerial vehicles). The terminal communication device, therefore, is any fixed, mobile, or portable equipment that performs the functions of the terminal device (terminal) described herein.

[0014] FIG. 1 A is a block diagram of a communication system 100 for an example of receive antenna management for Random Access Channel (RACH) preamble reception using spatial diversity. For the example, the system 100 includes a network node 102, a first terminal 104, and a second terminal 106. The system 100 may include any number for network nodes connected to a core network and serving any number of terminals in geographic regions. The network node includes a receiver antenna array 108 and a transmitter antenna array 110. In some situations, at least some of the antenna elements of the transmission antenna array 110 may be used by the receiver antenna array 108. Accordingly, a single antenna array may be used for both transmission andreception. A transmitter 112 transmits downlink signals through the transmitter antenna array 110 where antenna processing configures the transmitter antenna array to transmit antenna beams 114, 116 within an antenna pattern 118. For the example of FIG. 1 , a beam forming function 120 in the transmitter 112 facilitates beamforming. The beamforming may be performed by equipment outside of the transmitter 112 or by other electronics in some situations. For the example, the transmit antenna pattern 118 includes broadcasted cell beams 114, 116 that are used for synchronization and broadcasting information within the cell and more focused user beams tailored to individual terminals and primarily used for data transmission. The user beams (not shown in FIG. 1A) may be formed using a precoder (not shown) or other antenna matrix processing equipment.

[0015] For the example, the broadcasted cell beams are transmit antenna beams providing Synchronization Signal Blocks (SSBs) that include a Primary Synchronization Signals (PSS) and Secondary Synchronization Signals (SSS), as well as a Physical Broadcast Channel (PBCH) including demodulation reference signals (DMRS). Each SSB beam 114, 116 conveys a unique SSB index that identifies the SSB beam. The SSB beams are used for network access by terminals where the terminals scan and measure the SSB beams and select an SSB for downlink communication. A terminal accesses the network using a Random Access Channel process which can be used in situations requiring establishment or re-establishment of a connection such as, initial network access, handover, and beam failure recovery.

[0016] RACH procedures include Contention Based Random-Access (CBRA) procedures and Contention Free Random-Access (CFRA) procedures. These types differ in the allocated time, frequency resources as well as the allowed sequence indices. To access the network, a terminal transmits, to the network node, a RACH preamble with the appropriate parameters based on the SSB index. The network node transmits a System Information Block (SIB1 ) message within the cell periodically conveyed over the Physical Downlink Shared Channel (PDSCH) and signaled via the Common Control Resource Set (CORESET). The SIB1 message provides the RACH parameters for each SSB index. A RACH configuration index provides the timefrequency resources for the RACH Occasion (RO) for an SSB index. Based on theSIB1 , therefore, the terminal determines which resources to use for transmitting the RACH preamble for the SSB index that has been selected.

[0017] One or more revisions of the 3GPP communication specification govern RO resources for all RACH indexes and provide a mapping between the ROs and SSB Indexes where the mapping is based on msg1 -FDM and ssb-perRACH- OccasionAndCB-PreamblesPerSSB. The msg1 -FDM parameter specifies how many SSB indices are mapped by frequency domain multiplexing per each time domain resource of an RO. The ssb-perRACH-OccasionAndCB-PreamblesPerSSB parameter specifies how many SSB indexes are mapped into one RO in time domain as well as the number of available preambles for contention resolution. The parameters for each PRACH Config Index include a Preamble format, a System Frame Number (SFN), a slot number, a starting symbol, a number of PRACH slots within a 60 kHz slot, a number of time domain PRACH occasions within a PRACH slot and a PRACH duration. Based on the mapping and parameters, therefore, a particular RO may be the single RO available at a set of communication resources in some situations. In other situations, however, it is possible that more than one RO shares the same time-frequency resources.Therefore, a first RO associated with a first SSB beam may be the same as second RO associated with a second SSB beam adjacent to the first SSB beam.

[0018] For the example of FIG. 1 , the network node transmits a first SSB (SSB01 ) 122 in a first transmit beam 114 and a second SSB (SSB02) 124 in a second transmit beam 116. The first terminal 104 scans the SSBs and selects the first SSB (SSB01 ) 122 as the preferred SSB. The second terminal 106 scans the SSBs and selects the second SSB (SSB02) 124 as the preferred SSB. For the example, the terminals 104, 106 are engaging in a RACH process and have received RACH configuration indexes (not shown) in the SIB1 message (not shown) indicating that the first terminal 104 should send its RACH preamble at an RO having the same time-frequency resources as the RO for the second terminal 106 RACH preamble transmission. For the example, therefore, the RO for RACH transmissions associated with two adjacent transmit antenna beams 114, 116 is the same (i.e. using the same time-frequency resources)

[0019] With conventional systems, it is possible that a single receive antenna beam would receive both the RACH preambles and two RACH transmissions at the same ROwould interfere. This may be the case where the two transmit antenna beams are adjacent as discussed above and a single receive antenna beam covers the geographical area where each of multiple terminals may receive either one of the SSBs. In some situations, two transmit antenna beams associated with the same RO may not be adjacent but are still transmitting within an area covered by a single receive antenna beam which also results in interference between the two RACH transmissions.

[0020] For the examples herein, however, the receive antenna pattern includes two receive antenna beams 128, 130 providing spatial diversity for receiving the two RACH transmissions. After receiving the SIB1 and determining the RO, each terminal 104, 106 transmits a RACH preamble at the RO where the first terminal 104 transmits a first RACH preamble 132 and the second terminal 106 transmits a second RACH preamble 134. The first RACH preamble 132 is received by the receiver 136 via the first receive antenna beam 128 and the second RACH preamble 134 is received by the receiver 136 via the second receive antenna beam 130. Antenna processing in the receiver 136 performs beamforming to form the receive antenna pattern including the two receive antenna beams. Although the antenna processing, such as time domain beamforming, is typically considered to be part of the receiver chain, at least some of the antenna system functions may be formed by equipment considered to be outside of the receiver 136. In the interest of brevity and clarity, FIG. 1A shows only two receive antenna beams of the receive antenna pattern. For the example, the receive antenna pattern includes multiple receive antenna beams where each receive antenna beam coincides with a transmit antenna beam of the transmit antenna pattern 118. In some situations, the receive antenna pattern includes the minimum number of receive antenna beams for avoiding interference between RACH preamble transmissions. The receive antenna beams 128, 130 are drawn with cross-hatched lobes that are smaller than the transmit antenna beams to best illustrate the situation. The sizes of the shapes representing the antenna beams do not convey any information regarding beam strength. In typical situations, the transmit antenna beam pattern and the receive antenna pattern have multiple beams at different azimuth and elevation angles. The multiple lobes shown with dashed lines in FIG. 1A represent the additional beams of both antenna patterns which can have any number of beams.

[0021] FIG. 1 B is an illustration of an example of a portion of a transmission antenna radiation pattern 150 and a portion of a reception antenna radiation pattern 152 configured to minimize interference between RACH transmissions received at the network node 102. Accordingly, the antenna radiations patterns 150, 152 are examples of the antenna patterns in FIG. 1A. The receive antenna beams 128, 130 forming the portion of the reception radiation pattern 152 are represented by cross-hatched shapes where the shape represents a cross-section of a three-dimensional reception coverage space. The reception antenna radiation pattern 152 is a graphical representation of the radiation reception properties of the antenna as a function of space. The reception antenna radiation pattern 152 represents the relative intensity of the receiving energy radiation or the amount of the received electric or magnetic field strength as a function of the direction to the antenna. The reception antenna radiation pattern 152 represents how the antenna receives energy. Therefore, the outline of the shape representing the receive antenna beam can represent the maximum reception gain.

[0022] The transmission antenna radiation pattern 150 is a graphical representation of the radiation transmission properties of the antenna as a function of space. The transmission antenna radiation pattern 150 represents the relative intensity of the transmitted radiation energy or the amount of the transmitted electric or magnetic field strength as a function of the direction to the antenna. The transmission antenna radiation pattern 150 represents how the antenna transmits energy out into space. The shape representing an transmit antenna beam, therefore, can also represent the coverage area of the transmit antenna beam for a given reception power of a signal transmitted via the transmit antenna beam and received by a terminal within the shape. For the examples, the network node establishes the reception pattern 152 to align the receive antenna beams with the transmit antenna coverage areas of the transmit antenna beams of the transmission antenna pattern 150. For the example, the first transmit antenna beam 114 has a first coverage area 154 and the second transmit antenna beam has a second coverage area 156. The reception antenna pattern 152 is established such that each receive antenna beam 128, 130 has a maximum reception gain within only one of the coverage areas 154, 156 of the transmit beams. Therefore, the maximum reception gain of the first receive antenna beam 128 is directed only thefirst coverage area 154 and not any other coverage areas. Similarly, the maximum reception gain of the second receive antenna beam is directed only the second coverage area 156 of the second transmit antenna beam 116.

[0023] FIG. 1 C is an illustration of an example in conventional system of the relationship between a transmission antenna radiation pattern 150 and reception antenna radiation pattern 160. As compared to the examples of FIG. 1A and FIG. 1 B, conventional receive antenna beam 162 has a maximum reception gain that is directed to both coverage areas of the two transmit antenna beams 114, 116. As a result, a first RACH preamble transmitted by a terminal in the first coverage area 154 is likely to interfere with a RACH preamble transmitted by another terminal in the second coverage area 156 at the same RO.

[0024] FIG. 2 is a block diagram of an example of a base station 200 suitable for use as the network node 102. The base station 200 includes electronics (controller) 204, a communication interface 206, the transmitter 112, the receiver 136, the transmit antenna 110 and the receive antenna 108, as well as other electronics, hardware, and code. The base station 200 is any fixed, mobile, or portable equipment that performs the functions described herein. The various functions and operations of the blocks described with reference to the base station 200 and network node 104 may be implemented in any number of devices, circuits, or elements. Two or more of the functional blocks may be integrated in a single device, and the functions described as performed in any single device may be implemented over several devices. The base station 200 may be a fixed device or apparatus that is installed at a particular location at the time of system deployment. Examples of such equipment include fixed base stations or fixed transceiver stations. Although the base station may be referred to by different terms, the base station is typically referred to as a gNodeB or gNB when operating in accordance with one or more communication specifications of 3GPP. In some situations, the base station 200 may be mobile equipment that is temporarily installed at a particular location. Some examples of such equipment include mobile transceiver stations that may include power generating equipment such as electric generators, solar panels, and / or batteries. Larger and heavier versions of such equipment may be transported by trailer.

[0025] The electronics (controller) 204 includes any combination of hardware, software, and / or firmware for executing the functions described herein as well as facilitating the overall functionality of the base station 200. An example of suitable electronics 204 includes code running on a microprocessor or processor arrangement connected to memory. The transmitter 112 includes electronics configured to transmit wireless signals. In some situations, the transmitter 112 may include multiple transmitters. The receiver 136 includes electronics configured to receive wireless signals. In some situations, the receiver 136 may include multiple receivers. As discussed above, the antennas 108, 110 may share at least some antenna elements. Such an implementation may be advantageous in a system utilizing Time Division Duplex (TDD).

[0026] The transmitter 112 and receiver 136 perform radio frequency (RF) processing including modulation and demodulation. The receiver 136, therefore, may include components such as low noise amplifiers (LNAs) and filters. For the example, the receiver includes the time-domain beam forming module 138. The transmitter 112 may include filters and amplifiers as well as the beamforming module 120, a precoder, and other antenna system components. Other components may include isolators, matching circuits, and other RF components. These components in combination or cooperation with other components perform the base station functions. The required components may depend on the particular functionality required by the base station.

[0027] The transmitter 112 includes a modulator (not shown), and the receiver 136 includes a demodulator (not shown). The modulator modulates the signals to be transmitted as part of the downlink signals and can apply any one of a plurality of modulation orders. The demodulator demodulates any uplink signals received at the base station 200 in accordance with one of a plurality of modulation orders. The controller 204 in conjunction with the beamforming module 120 and the transmitter 112 process the signals transmitted through the transmit antenna 110. The controller 204 in conjunction with the beamforming module 138 and the receiver 136 configure the receive antenna pattern of the antenna 108 and process the signals received through the antenna 108.

[0028] The base station 200 includes a communication interface 206 for transmitting and receiving messages with other base stations and / or network entities. The communication interface 206 may be connected to a backhaul or network enabling communication with other base stations. In some situations, the link between base stations may include at least some wireless portions. The communication interface 206, therefore, may include wireless communication functionality and may utilize some of the components of the transmitter 112 and / or receiver 136.

[0029] FIG. 3 is a block diagram of an example of a user equipment (UE) device 300 suitable for use as either of the terminal 104, 106. In some examples, the UE device 300 is any wireless communication device such as a mobile phone, a transceiver modem, a personal digital assistant (PDA), a tablet, or a smartphone. In other examples, the UE device 300 is a machine type communication (MTC) communication device or Internet-of-Things (IOT) device. The UE device 300, therefore is any fixed, mobile, or portable equipment that performs the functions described herein. The various functions and operations of the blocks described with reference to UE device 300 may be implemented in any number of devices, circuits, or elements. Two or more of the functional blocks may be integrated in a single device, and the functions described as performed in any single device may be implemented over several devices.

[0030] The UE device 300 includes at least electronics (controller) 302, a transmitter 304 and a receiver 306. The electronics (controller) 302 include any combination of hardware, software, and / or firmware for executing the functions described herein as well as facilitating the overall functionality of a communication device. An example of a suitable controller 302 includes code running on a microprocessor or processor arrangement connected to memory 310. The transmitter 304 includes electronics configured to transmit wireless signals. In some situations, the transmitter 304 may include multiple transmitters. The receiver 306 includes electronics configured to receive wireless signals. In some situations, the receiver 306 may include multiple receivers. The receiver 306 and transmitter 304 receive and transmit signals, respectively, through antenna 308. The antenna 308 may include separate transmitand receive antennas. In some circumstances, the antenna 308 may include multiple transmit and receive antennas.

[0031] The transmitter 304 and receiver 306 in the example of FIG. 3 perform radio frequency (RF) processing including modulation and demodulation. The receiver 306, therefore, may include components such as low noise amplifiers (LNAs) and filters. The transmitter 304 may include filters and amplifiers. Other components may include isolators, matching circuits, and other RF components. These components in combination or cooperation with other components perform the communication device functions. The required components may depend on the particular functionality required by the communication device.

[0032] The transmitter 304 includes a modulator (not shown), and the receiver 306 includes a demodulator (not shown). The modulator can apply any one of a plurality of modulation orders to modulate the signals to be transmitted as part of the uplink signals. The demodulator demodulates the downlink signals in accordance with one of a plurality of modulation orders.

[0033] The UE device 300 is capable of transmitting and receiving sidelink signals to and from other UE devices as well as communicating with a base station (network node). The receiver 306 and controller 302 also measure signals transmitted by the network node to select a preferred SSB and to perform RACH functions described herein.

[0034] FIG. 4 is a flow chart of an example of a method of spatially multiplexing RACH preamble reception. For the example, the method is performed by a network node, such as the network node 102. The method may be performed using any of several techniques involving any combination of software, hardware, and firmware. For example, software code running on electronics including a processor, computer or other processor arrangement within the network node may facilitate the generation, formatting, reception, and transmission of signals and messages as well as facilitating measurements, evaluations and determinations. One or more of the steps may be omitted, combined, performed in parallel, or performed in a different order than that described herein or shown in FIG. 4. In still further examples, additional steps may beadded that are not explicitly described in connection with the example discussed with reference to FIG. 4.

[0035] At step 402, the network node 102 transmits a first reference signal over a first transmit antenna beam of a plurality of transmit antenna beams. The first reference signal indicates a first index associated with the first transmit antenna beam.

[0036] At step 404, the network node 102 transmits a second reference signal over a second transmit antenna beam of the plurality of transmit antenna beams. The second reference signal indicates a second index associated with the second transmit antenna beam. For the example, the reference signals are SSBs and each index is an SSB index.

[0037] As step 406. the network node 102 establishes a receive antenna pattern having a plurality of receive antenna beams where a first receive antenna beam is associated with the first transmit antenna beam and a second receive antenna beam associated with the second transmit antenna beam. Using time-domain beam forming, the network node 102 configures the first receive antenna beam to be directed to the coverage area of the first transmit antenna beam and configures the second receive antenna beam to be directed to the coverage area of the second transmit antenna beam.

[0038] At step 408, the network node 102 receives, from a first terminal, a first uplink signal over the first receive antenna beam at a time-frequency communication resource. For the example, the network node 102 receives first RACH preamble transmitted from the first terminal at an RO.

[0039] At step 410, the network node 102 receives, from a second terminal, a second uplink signal over the second receive antenna beam at the time-frequency communication resource where the time-frequency communication resource is allocated for uplink transmissions associated with the first index and the second index. Accordingly, the first uplink signal and the second uplink signal are received over the same communication resources but through different receive antenna beams. For the example, the network node 102 receives a second RACH preamble transmitted from the second terminal at the same RO as the first RACH preamble.

[0040] To clearly illustrate this interchangeability of hardware, firmware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware, firmware or software, or a combination of these techniques, depends upon the particular application and design constraints imposed on the overall system. The described functionality may be implemented in various ways for each particular application, but such implementation decisions do not cause a departure from the scope of the present disclosure. In accordance with various embodiments, a processor, device, component, circuit, structure, machine, module, etc. can be configured to perform one or more of the functions described herein. The term "configured to" or "configured for" as used herein with respect to a specified operation or function refers to processors, devices, components, circuits, electronics, and equipment that are physically constructed, programmed, instructed and / or arranged to perform the specified operation or function. Furthermore, the various illustrative logical blocks, modules, devices, components and circuits described herein can be implemented within or performed by an integrated circuit (IC) that can include a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), other electronics or combinations thereof. (ASIC), a field programmable gate array (FPGA) or other programmable logic device, or any combination thereof. The logical blocks, electronics, and circuits can further include antennas and / or transceivers to communicate with various components within the network or within the device. A general-purpose processor can be a microprocessor, but in the alternative, the processor can be any conventional processor, controller, or state machine. A processor can also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other suitable configuration to perform the functions described herein.

[0041] When implemented in software, the functions can be stored as one or more instructions or code on a computer-readable medium. Thus, the steps of a method or algorithm disclosed herein can be implemented as software stored on a computer- readable medium. Computer readable media includes both computer storage mediaand communication media, including any medium that can be enabled to transfer a computer program or code from one place to another. A storage media can be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer.

[0042] Therefore, the methods and apparatus of this invention may take the form, at least partially, of program logic or program code (i.e., instructions) embodied in tangible media, such as a machine-readable storage medium. When the program code is loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the invention. The methods and apparatus of the present invention may also be embodied in the form of program code that is transmitted over some transmission medium, such as over electrical wiring or cabling, through fiber optics, or via any other form of transmission. When the program code is received and loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the invention. When implemented on a general-purpose processor, the program code combines with the processor to provide a unique apparatus that operates analogously to specific logic circuits.

[0043] Additionally, memory or other storage, as well as communication components, may be employed in embodiments of the present disclosure. It will be appreciated that, for clarity purposes, the above description has described embodiments of the present disclosure with reference to different functional units and processors. However, it will be apparent that any suitable distribution of functionality between different functional units, processing logic elements or domains may be used without detracting from the present disclosure. For example, functionality illustrated to be performed by separate processing logic elements, or controllers, may be performed by the same processing logic element, or controller. Therefore, references to specific functional units are only references to a suitable means for providing the described functionality, rather than indicative of a strict logical or physical structure or organization.

[0044] Clearly, other embodiments and modifications of this invention will occur readily to those of ordinary skill in the art in view of these teachings. The above description is illustrative and not restrictive. This invention is to be limited only by the following claims, which include all such embodiments and modifications when viewed in conjunction with the above specification and accompanying drawings. The scope of the invention should, therefore, be determined not with reference to the above description, but instead should be determined with reference to the appended claims along with their full scope of equivalents.

Claims

CLAIMS1 . A method comprising: transmitting a first reference signal over a first transmit antenna beam of a plurality of transmit antenna beams, the first reference signal indicating a first index associated with the first transmit antenna beam; transmitting a second reference signal over a second transmit antenna beam of the plurality of transmit antenna beams, the second reference signal indicating a second index associated with the second transmit antenna beam; establishing a receive antenna pattern of a receive antenna having a plurality of receive antenna beams, a first receive antenna beam associated with the first transmit antenna beam, a second receive antenna beam associated with the second transmit antenna beam; receiving, from a first terminal, a first uplink signal over the first receive antenna beam at a time-frequency communication resource; and receiving, from a second terminal, a second uplink signal over the second receive antenna beam at the time-frequency communication resource, the timefrequency communication resource allocated for uplink transmissions associated with the first index and the second index.

2. The method of claim 1 , wherein establishing the receive antenna pattern comprises: time domain beamforming the first receive antenna beam; and time domain beamforming the second receive antenna beam.

3. The method of claim 1 , wherein: the first reference signal comprises a first Synchronization Signal Block (SSB); the second reference signal comprises a second SSB; the first uplink signal is a first Random Access Channel (RACH) preamble transmission at a RACH Occasion (RO); and the second uplink signal is a second RACH preamble transmission at the RO.

4. The method of claim 3, further comprising: broadcasting a System Information Block 1 (SIB1 ) message over the first transmit antenna beam and the second antenna beam, the SIB1 comprising RACH configuration information identifying the time frequency communication resource and the RO.

5. The method of claim 1 , wherein the second transmit antenna beam is adjacent to the first transmit antenna beam.

6. The method of claim 1 , wherein the plurality of transmit antenna beams are formed by a transmit antenna different from the receive antenna.

7. The method of claim 1 , wherein the plurality of transmit antenna beams are formed by antenna elements of the receive antenna.

8. The method of claim 1 , wherein the first receive antenna beam has a maximum reception gain directed to a first coverage area of the first transmit antenna beam and the second receive antenna beam has a maximum reception gain directed only to a second coverage area of the second transmit antenna beam.

9. The method of claim 1 , wherein the receive antenna pattern comprises a plurality of receive antenna beams and the transmit antenna pattern comprises a plurality of transmit antenna beams, each receive antenna beam having a maximum reception gain directed to only to a coverage area of a single transmit antenna beam.

10. A network node comprising: a transmit antenna array configured for transmissions through a plurality of transmit antenna beams forming a transmit antenna pattern; a receive antenna array configured for reception through a plurality of receive antenna beams;a transmitter configured to transmit a reference signal through each transmit antenna beam of the plurality of transmit antenna beams, each reference signal indicating a unique index; and a receiver configured to receive, from a first terminal, a first uplink signal over a first receive antenna beam at a time-frequency communication resource and to receive from a second terminal, a second uplink signal over the second receive antenna beam at the time-frequency communication resource, the time-frequency communication resource allocated for uplink transmissions associated with a first index of a first reference signal transmitted with a first transmit antenna beam and with a second index of a second reference signal transmitted with a second transmit antenna beam.

11. The network node of claim 10, further comprising an antenna beamforming module configured to: time domain beamform the first receive antenna beam; and time domain beamform the second receive antenna beam.

12. The network node of claim 10, wherein: the first reference signal comprises a first Synchronization Signal Block (SSB); the second reference signal comprises a second SSB; the first uplink signal is a first Random Access Channel (RACH) preamble transmission at a RACH Occasion (RO); and the second uplink signal is a second RACH preamble transmission at the RO.

13. The network node of claim 12, further comprising: broadcasting a System Information Block 1 (SIB1 ) message over the plurality of transmit antenna beams, the SIB1 comprising RACH configuration information identifying the time frequency communication resource and the RO.

14. The network node of claim 10, wherein the second transmit antenna beam is adjacent to the first transmit antenna beam.

15. The network node of claim 10, wherein the plurality of transmit antenna beams are formed by a transmit antenna different from the receive antenna.

16. The network node of claim 10, wherein the plurality of transmit antenna beams are formed by antenna elements of the receive antenna.

17. The network node of claim 10, wherein the first receive antenna beam has a maximum reception gain directed to a first coverage area of the first transmit antenna beam and the second receive antenna beam has a maximum reception gain directed only to a second coverage area of the second transmit antenna beam.

18. The network node of claim 10, wherein the receive antenna pattern comprises a plurality of receive antenna beams and each receive antenna beam has a maximum reception gain directed only to a coverage area of a single transmit antenna beam.

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