WO2024123325A1

WO2024123325A1 - Apparatus and method for timer-based robust header compression for real-time protocol time stamp compression

Info

Publication number: WO2024123325A1
Application number: PCT/US2022/052121
Authority: WO
Inventors: Su-Lin Low; Na CHEN
Original assignee: Zeku Inc
Current assignee: Zeku Inc
Priority date: 2022-12-07
Filing date: 2022-12-07
Publication date: 2024-06-13
Anticipated expiration: 2025-06-07

Abstract

According to one aspect of the present disclosure, a wireless device is provided. The wireless device may include an application processor that generates a real-time protocol (RTP) packet with an RTP header that includes a timestamp (TS) field. The wireless device may include a robust header compression (ROHC) microcontroller (uC). The ROHC uC may receive the RTP packet with the RTP header including the TS field. The ROHC uC may identify a jitter delay associated with the RTP packet based at least in part on the TS field in the RTP header. The ROHC uC may perform a timer-based timestamp ROHC procedure to select a number of bits for compressing the RTP header, where the number of bits covers less than a maximum jitter range associated with RTP-packet traffic. The ROHC uC may compress the RTP header to the number of bits selected by the timer-based timestamp ROHC procedure.

Description

APPARATUS AND METHOD FOR TIMER-BASED ROBUST HEADER COMPRESSION FOR REAL-TIME PROTOCOL TIME STAMP COMPRESSION

BACKGROUND

[0001] Embodiments of the present disclosure relate to apparatus and method for wireless communication.

[0002] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. In cellular communication, such as the 4th-gen eration (4G) Long Term Evolution (LTE) and the 5th- generation (5G) New Radio (NR), the 3rd Generation Partnership Project (3GPP) defines various procedures for robust header compression (ROHC).

SUMMARY

[0003] According to one aspect of the present disclosure, a wireless device is provided. The wireless device may include an application processor configured to generate a real-time protocol (RTP) packet with an RTP header that includes a timestamp (TS) field. The wireless device may include a dataplane (DP) subsystem with a robust header compression (ROHC) microcontroller (uC). The ROHC uC may be configured to receive, from the application processor, the RTP packet with the RTP header including the TS field. The ROHC uC may be configured to identify a jitter delay associated with the RTP packet based at least in part on the TS field in the RTP header. The ROHC uC may be configured to perform a timer-based timestamp ROHC procedure to select a number of bits for compressing the RTP header, the number of bits covering less than a maximum jitter range associated with RTP -packet traffic. The ROHC uC may be configured to compress the RTP header to the number of bits selected by the timer-based timestamp ROHC procedure.

[0004] According to another aspect of the present disclosure, an apparatus for wireless communication of a UE is provided. The apparatus may include a baseband chip. The baseband chip may include an application processor configured to generate an RTP packet with an RTP header that includes a TS field. The baseband chip may include a DP subsystem with a ROHC uC. The ROHC uC may be configured to receive, from the application processor, the RTP packet with the RTP header including the TS field. The ROHC uC may be configured to identify a jitter delay associated with the RTP packet based at least in part on the TS field in the RTP header. The ROHC uC may be configured to perform a timer-based timestamp ROHC procedure to select a number of bits for compressing the RTP header, the number of bits covering less than a maximum jitter range associated with RTP-packet traffic. The ROHC uC may be configured to compress the RTP header to the number of bits selected by the timer-based timestamp ROHC procedure.

[0005] According to yet another aspect of the present disclosure, a method of wireless communication of a wireless device is provided. The method may include generating, by an application processor, an RTP packet with an RTP header that includes a TS field. The method may include receiving, by a ROHC uC of a DP subsystem, the RTP packet with the RTP header including the TS field from the application processor. The method may include identifying, by the ROHC uC of the DL DP subsystem, a jitter delay associated with the RTP packet based at least in part on the TS field in the RTP header. The method may include performing, by the ROHC uC of the DL DP subsystem, a timer-based timestamp ROHC procedure to select a number of bits for compressing the RTP header, the number of bits covering less than a maximum jitter range associated with RTP-packet traffic. The method may include compressing, by the ROHC uC of the DL DP subsystem, the RTP header to the number of bits selected by the timer-based timestamp ROHC procedure.

[0006] These illustrative embodiments are mentioned not to limit or define the present disclosure, but to provide examples to aid understanding thereof. Additional embodiments are discussed in the Detailed Description, and further description is provided there.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate embodiments of the present disclosure and, together with the description, further serve to explain the principles of the present disclosure and to enable a person skilled in the pertinent art to make and use the present disclosure.

[0008] FIG. 1 illustrates an exemplary wireless network, according to some embodiments of the present disclosure.

[0009] FIG. 2 illustrates a block diagram of an exemplary node, according to some embodiments of the present disclosure.

[0010] FIG. 3 illustrates a detailed block diagram of an exemplary baseband chip, according to some embodiments of the present disclosure. [0011] FIG. 4 illustrates an exemplary call flow for operations associated with the timerbased ROHC procedure for RTP header compression by the exemplary baseband chip of FIG. 3, according to some embodiments of the present disclosure

[0012] FIG. 5 illustrates an exemplary RTP packet header with compressible fields, according to some embodiments of the present disclosure.

[0013] FIG. 6 illustrates a target jitter range used in the timer-based ROHC procedure for RTP header compression by the exemplary baseband chip of FIG. 3, according to some embodiments of the present disclosure.

[0014] FIG. 7 illustrates an exemplary technique for deriving jitter statistics of windowbased least significant bits (WLSB) values used in the timer-based ROHC procedure for RTP header compression by the exemplary baseband chip of FIG. 3, according to some embodiments of the present disclosure.

[0015] FIG. 8 illustrates a exemplary technique for identifying bounds of a target quality - of-service (QoS) confidence interval range, according to some embodiments of the present disclosure.

[0016] FIG. 9 illustrates an exemplary technique for identifying outliers in the target QoS confidence interval range, according to some embodiments of the present disclosure.

[0017] FIGs. 10A-10C are a flowchart of an exemplary method of wireless communication, according to some aspects of the present disclosure.

[0018] Embodiments of the present disclosure will be described with reference to the accompanying drawings.

DETAILED DESCRIPTION

[0019] Although specific configurations and arrangements are discussed, it should be understood that this is done for illustrative purposes only. A person skilled in the pertinent art will recognize that other configurations and arrangements can be used without departing from the spirit and scope of the present disclosure. It will be apparent to a person skilled in the pertinent art that the present disclosure can also be employed in a variety of other applications.

[0020] It is noted that references in the specification to “one embodiment,” “an embodiment,” “an example embodiment,” “some embodiments,” “certain embodiments,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases do not necessarily refer to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it would be within the knowledge of a person skilled in the pertinent art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0021] In general, terminology may be understood at least in part from usage in context. For example, the term “one or more” as used herein, depending at least in part upon context, may be used to describe any feature, structure, or characteristic in a singular sense or may be used to describe combinations of features, structures or characteristics in a plural sense. Similarly, terms, such as “a,” “an,” or “the,” again, may be understood to convey a singular usage or to convey a plural usage, depending at least in part upon context. In addition, the term “based on” may be understood as not necessarily intended to convey an exclusive set of factors and may, instead, allow for existence of additional factors not necessarily expressly described, again, depending at least in part on context.

[0022] Various aspects of wireless communication systems will now be described with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, modules, units, components, circuits, steps, operations, processes, algorithms, etc. (collectively referred to as “elements”). These elements may be implemented using electronic hardware, firmware, computer software, or any combination thereof. Whether such elements are implemented as hardware, firmware, or software depends upon the particular application and design constraints imposed on the overall system.

[0023] The techniques described herein may be used for various wireless communication networks, such as code division multiple access (CDMA) system, time division multiple access (TDMA) system, frequency division multiple access (FDMA) system, orthogonal frequency division multiple access (OFDMA) system, single-carrier frequency division multiple access (SC- FDMA) system, wireless local area network (WLAN) system, and other networks. The terms “network” and “system” are often used interchangeably. A CDMA network may implement a radio access technology (RAT), such as Universal Terrestrial Radio Access (UTRA), evolved UTRA (E-UTRA), CDMA 1000, etc. A TDMA network may implement a RAT, such as the Global System for Mobile Communications (GSM). An OFDMA network may implement a RAT, such as LTE or NR. A WLAN system may implement a RAT, such as Wi-Fi. The techniques described herein may be used for the wireless networks and RATs mentioned above, as well as other wireless networks and RATs.

[0024] Small-packet communication services, e.g., such as voice over internet protocol (VoIP), voice over RN (VoNR), internet-of-things (loT), industrial loT (IIoT), interactive games, virtual reality (VR), augmented reality (AR), messaging, etc., in the 5G NR network may use ROHC to compress the headers (e.g., Robust Header Compression (ROHC) is a standardized method to compress the headers of small packets such as IP packets, user datagram protocol (UDP), real-time protocol (RTP), etc. ROHC may reduce header the overhead of voice packet transmissions, which lowers the block error rate (BER), reduces latency, and limits resource block (RB) consumption.

[0025] In the context of VoIP communications, ROHC may be useful since the header of the VoIP packets is much larger than the payload data it carries. For example, the payload of a VoIP packet may include around 32 bytes of payload voice data and 60 bytes of header. Thus, VoIP is a good candidate for ROHC to reduce the size of the header that is transmitted over the air. Moreover, while voice traffic tends to be very small in terms of data size, it has very frequent transmission. So, ROHC provides an efficient solution to reduce the number of RBs sent over the air.

[0026] In the ROHC compression procedure, the ROHC protocol analyzes the incoming IP/UDP/RTP headers for compression. These headers include static and semi-static fields, which never or seldom change or can be inferred, and hence there is no need to send these fields every time to the decompressor. On the other hand, there are 3 main dynamic changing fields which are the main targets for compression by the ROHC protocol, e.g., namely, the RTP Sequence Number (SN), RTP TimeStamp (TS), and IP Identification (IPID) fields. Specifically, the 32-bit TS field can be compressed effectively via the ROHC Timer-based TS compression technique, if there are unavoidable random packet jitter delays and multiple silent gaps in the interarrival times.

[0027] In this Timer-based TS compression scheme, the number of k bits used to encode the TS field needs to cover the jitter delay range, such that the peer decompressor on the network side can recover the full header successfully. In essence, if the random interarrival times and jitter delays are large, the number of k bits may be very large, close to 32 bits if necessary, even if there are only a few occasional outliers. This causes unnecessary compression and a low, inefficient compression ratio, while increasing the consumption of transmission resources and power. On the other hand, if the number of k bits is limited to a fixed number, there may be insufficient bits to cover the nominal jitter range of the IP multimedia subsystem (IMS) application traffic, which may lead to decompression failure and/or high error rates. For example, in some systems, the Timerbased TS ROHC technique uses a fixed number of k bits, which covers the maximum jitter range for incoming packets, which may be a large value if there are large jitters in the input stream. In some other systems, the fixed number k bits may not cover the full jitter range, thereby causing decompression error with truncated bits or transmitting more bits than necessary if the jitter range is low.

[0028] These Timer-based TS ROHC techniques from 1) an inefficient and unnecessary transmission of long compression bits for delay sensitive traffic, 2) an inability to differentiate the compression requirements of different quality-of-service (QoS) flows, 3) an unnecessary consumption of central processing unit (CPU) resources for small-packet, low-throughput traffic such as VoIP and IIOT traffic, 4) undesirable power consumption for VoIP and IIoT traffic, 5) a large memory and/or processor footprint, 6) a large number of microcontroller (uC) million instructions per second (MIPs) cycles, 7) an inability to adjust resource utilization based on traffic patterns and/or throughput, and 8) an inefficient utilization of baseband chip resources to process the VoIP protocol stack across multiple processors and resources, just to name a few.

[0029] Thus, there exists an unmet need for a Timer-based TS ROHC technique that optimizes the number of bits selected for TS compression to reduce signaling overhead, while at the same time lowering the power consumption at the baseband chip.

[0030] To overcome these and other challenges, the present disclosure provides an exemplary Timer-based TS ROHC technique that optimizes the small-packet transmission with a high-compression ratio. This may be achieved by selecting the number of bits used to compress the TS header based on the QoS flow of the packet, thereby reducing the power consumption at the baseband chip. To that end, the present Timer-based TS ROHC technique may derive/calculate jitter statistics associated with a window-based least significant bits (LSB) (WLSB) WLSB history of RTP -packet traffic. These statistics may provide dynamic insights into the jitter delay distribution as a function of time for each incoming packet. The jitter statistics may be used as inputs to discard outlier RTP packets with large jitters, as well as the selection algorithm for QoSbased TS compression. Once the jitter pattern statistics are derived, the bounds for the target QoS confidence interval within the jitter range is mapped. Based on the maximum and minimum bounds, the smallest number of k bits for TS compression may be identified. In this way, the exemplary Timer-based TS ROHC technique provides a dynamic selection of TS field compression bits based on the QoS flow associated with the RTP packet. Additional details of the exemplary Timer-based TS ROHC technique are provided below in connection with FIGs. 1-10C. [0031] FIG. 1 illustrates an exemplary wireless network 100, in which some aspects of the present disclosure may be implemented, according to some embodiments of the present disclosure. As shown in FIG. 1, wireless network 100 may include a network of nodes, such as user equipment 102, an access node 104, and a core network element 106. User equipment 102 may be any terminal device, such as a mobile phone, a desktop computer, a laptop computer, a tablet, a vehicle computer, a gaming console, a printer, a positioning device, a wearable electronic device, a smart sensor, or any other device capable of receiving, processing, and transmitting information, such as any member of a vehicle to everything (V2X) network, a cluster network, a smart grid node, or an Internet-of-Things (loT) node. It is understood that user equipment 102 is illustrated as a mobile phone simply by way of illustration and not by way of limitation.

[0032] Access node 104 may be a device that communicates with user equipment 102, such as a wireless access point, a base station (BS), a Node B, an enhanced Node B (eNodeB or eNB), a next-generation NodeB (gNodeB or gNB), a cluster master node, or the like. Access node 104 may have a wired connection to user equipment 102, a wireless connection to user equipment 102, or any combination thereof. Access node 104 may be connected to user equipment 102 by multiple connections, and user equipment 102 may be connected to other access nodes in addition to access node 104. Access node 104 may also be connected to other user equipments. When configured as a gNB, access node 104 may operate in millimeter wave (mmW) frequencies and/or near mmW frequencies in communication with the user equipment 102. When access node 104 operates in mmW or near mmW frequencies, the access node 104 may be referred to as an mmW base station. Extremely high frequency (EHF) is part of the radio frequency (RF) in the electromagnetic spectrum. EHF has a range of 30 GHz to 200 GHz and a wavelength between 1 millimeter and 10 millimeters. Radio waves in the band may be referred to as a millimeter wave. Near mmW may extend down to a frequency of 3 GHz with a wavelength of 100 millimeters. The super high frequency (SHF) band extends between 3 GHz and 30 GHz, also referred to as centimeter wave. Communications using the mmW or near mmW radio frequency band have extremely high path loss and a short range. The mmW base station may utilize beamforming with user equipment 102 to compensate for the extremely high path loss and short range. It is understood that access node 104 is illustrated by a radio tower by way of illustration and not by way of limitation.

[0033] Access nodes 104, which are collectively referred to as E-UTRAN in the evolved packet core network (EPC) and as NG-RAN in the 5G core network (5GC), interface with the EPC and 5GC, respectively, through dedicated backhaul links (e.g., SI interface). In addition to other functions, access node 104 may perform one or more of the following functions: transfer of user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment trace, RAN information management (RIM), paging, positioning, and delivery of warning messages. Access nodes 104 may communicate directly or indirectly (e.g., through the 5GC) with each other over backhaul links (e.g., X2 interface). The backhaul links may be wired or wireless.

[0034] Core network element 106 may serve access node 104 and user equipment 102 to provide core network services. Examples of core network element 106 may include a home subscriber server (HSS), a mobility management entity (MME), a serving gateway (SGW), or a packet data network gateway (PGW). These are examples of core network elements of an evolved packet core (EPC) system, which is a core network for the LTE system. Other core network elements may be used in LTE and in other communication systems. In some embodiments, core network element 106 includes an access and mobility management function (AMF), a session management function (SMF), or a user plane function (UPF) of the 5GC for the NR system. The AMF may be in communication with a Unified Data Management (UDM). The AMF is the control node that processes the signaling between the user equipment 102 and the 5GC. Generally, the AMF provides QoS flow and session management. All user Internet protocol (IP) packets are transferred through the UPF. The UPF provides user equipment (UE) IP address allocation as well as other functions. The UPF is connected to the IP Services. The IP Services may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), a PS Streaming Service, and/or other IP services. It is understood that core network element 106 is shown as a set of rack-mounted servers by way of illustration and not by way of limitation.

[0035] Core network element 106 may connect with a large network, such as the Internet 108, or another Internet Protocol (IP) network, to communicate packet data over any distance. In this way, data from user equipment 102 may be communicated to other user equipments connected to other access points, including, for example, a computer 110 connected to Internet 108, for example, using a wired connection or a wireless connection, or to a tablet 112 wirelessly connected to Internet 108 via a router 114. Thus, computer 110 and tablet 112 provide additional examples of possible user equipments, and router 114 provides an example of another possible access node. [0036] A generic example of a rack-mounted server is provided as an illustration of core network element 106. However, there may be multiple elements in the core network including database servers, such as a database 116, and security and authentication servers, such as an authentication server 118. Database 116 may, for example, manage data related to user subscription to network services. A home location register (HLR) is an example of a standardized database of subscriber information for a cellular network. Likewise, authentication server 118 may handle authentication of users, sessions, and so on. In the NR system, an authentication server function (AUSF) device may be the entity to perform user equipment authentication. In some embodiments, a single server rack may handle multiple such functions, such that the connections between core network element 106, authentication server 118, and database 116, may be local connections within a single rack.

[0037] Each element in FIG. 1 may be considered a node of wireless network 100. More detail regarding the possible implementation of a node is provided by way of an example in the description of a node 200 in FIG. 2. Node 200 may be configured as user equipment 102, access node 104, or core network element 106 in FIG. 1. Similarly, node 200 may also be configured as computer 110, router 114, tablet 112, database 116, or authentication server 118 in FIG. 1. As shown in FIG. 2, node 200 may include a processor 202, a memory 204, and a transceiver 206. These components are shown as connected to one another by a bus, but other connection types are also permitted. When node 200 is user equipment 102, additional components may also be included, such as a user interface (UI), sensors, and the like. Similarly, node 200 may be implemented as a blade in a server system when node 200 is configured as core network element 106. Other implementations are also possible.

[0038] Transceiver 206 may include any suitable device for sending and/or receiving data. Node 200 may include one or more transceivers, although only one transceiver 206 is shown for simplicity of illustration. An antenna 208 is shown as a possible communication mechanism for node 200. Multiple antennas and/or arrays of antennas may be utilized for receiving multiple spatially multiplex data streams. Additionally, examples of node 200 may communicate using wired techniques rather than (or in addition to) wireless techniques. For example, access node 104 may communicate wirelessly to user equipment 102 and may communicate by a wired connection (for example, by optical or coaxial cable) to core network element 106. Other communication hardware, such as a network interface card (NIC), may be included as well.

[0039] As shown in FIG. 2, node 200 may include processor 202. Although only one processor is shown, it is understood that multiple processors can be included. Processor 202 may include microprocessors, microcontroller units (MCUs), digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functions described throughout the present disclosure. Processor 202 may be a hardware device having one or more processing cores. Processor 202 may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Software can include computer instructions written in an interpreted language, a compiled language, or machine code. Other techniques for instructing hardware are also permitted under the broad category of software. [0040] As shown in FIG. 2, node 200 may also include memory 204. Although only one memory is shown, it is understood that multiple memories can be included. Memory 204 can broadly include both memory and storage. For example, memory 204 may include random-access memory (RAM), read-only memory (ROM), static RAM (SRAM), dynamic RAM (DRAM), ferroelectric RAM (FRAM), electrically erasable programmable ROM (EEPROM), compact disc readonly memory (CD-ROM) or other optical disk storage, hard disk drive (HDD), such as magnetic disk storage or other magnetic storage devices, Flash drive, solid-state drive (SSD), or any other medium that can be used to carry or store desired program code in the form of instructions that can be accessed and executed by processor 202. Broadly, memory 204 may be embodied by any computer-readable medium, such as a non-transitory computer-readable medium.

[0041] Processor 202, memory 204, and transceiver 206 may be implemented in various forms in node 200 for performing wireless communication functions. In some embodiments, at least two of processor 202, memory 204, and transceiver 206 are integrated into a single system- on-chip (SoC) or a single system-in-package (SiP). In some embodiments, processor 202, memory 204, and transceiver 206 of node 200 are implemented (e.g., integrated) on one or more SoCs. In one example, processor 202 and memory 204 may be integrated on an application processor (AP) SoC (sometimes known as a “host,” referred to herein as a “host chip”) that handles application processing in an operating system (OS) environment, including generating raw data to be transmitted. In another example, processor 202 and memory 204 may be integrated on a baseband processor (BP) SoC (sometimes known as a “modem,” referred to herein as a “baseband chip”) that converts the raw data, e.g., from the host chip, to signals that can be used to modulate the carrier frequency for transmission, and vice versa, which can run a real-time operating system (RTOS). In still another example, processor 202 and transceiver 206 (and memory 204 in some cases) may be integrated on an RF SoC (sometimes known as a “transceiver,” referred to herein as an “RF chip”) that transmits and receives RF signals with antenna 208. It is understood that in some examples, some or all of the host chip, baseband chip, and RF chip may be integrated as a single SoC. For example, a baseband chip and an RF chip may be integrated into a single SoC that manages all the radio functions for cellular communication.

[0042] Referring back to FIG. 1, in some embodiments, user equipment 102 may perform the exemplary Timer-based TS ROHC technique to optimize the small-packet transmission with a high-compression ratio. This may be achieved by selecting the number of bits used to compress the TS header based on the QoS flow of the packet, thereby reducing the power consumption at its baseband chip.

[0043] FIG. 3 illustrates a detailed block diagram of an exemplary baseband chip 300, according to some embodiments of the present disclosure. FIG. 4 illustrates an exemplary call flow for operations 400 associated with the timer-based ROHC procedure for RTP header compression by the exemplary baseband chip 300 of FIG. 3, according to some embodiments of the present disclosure. FIG. 5 illustrates an exemplary RTP packet header 500 with compressible fields, according to some embodiments of the present disclosure. FIG. 6 illustrates a target jitter range 600 used in the timer-based ROHC procedure for RTP header compression by the exemplary baseband chip 300 of FIG. 3, according to some embodiments of the present disclosure. FIG. 7 illustrates an exemplary technique for deriving jitter statistics 700 based on WLSB values used in the timer-based ROHC procedure for RTP header compression by the exemplary baseband chip 300 of FIG. 3, according to some embodiments of the present disclosure. FIG. 8 illustrates an exemplary technique 800 for identifying bounds of a target QoS confidence interval range, according to some embodiments of the present disclosure. FIG. 9 illustrates an exemplary technique 900 for identifying outliers in the target QoS confidence interval range, according to some embodiments of the present disclosure. FIGs. 3-9 will be described together.

[0044] Referring to FIG. 3, exemplary baseband chip 300 (referred to hereinafter as “baseband chip 300”) may include, e.g., a downlink (DL) physical layer (PHY) subsystem 302a, an uplink (UL) PHY subsystem 302b, a DP subsystem 304, a control plane subsystem 312, an application processor (AP)/host 314, and external connectivity network applications 316. AP/host 314 may be part of baseband chip 300 or external to baseband chip 300.

[0045] Still referring to FIG. 3, the DP subsystem 304 may include a DL dataplane (DP) subsystem 306a, which includes a ROHC uC 308a with a ROHC compressor 310a and a ROHC decompressor 310b. The DP subsystem 304 may also include a UL DP subsystem 306b with a logical channel prioritization (LCP) uC 308b.

[0046] ROHC compressor 310a may communicate with the IMS applications (e.g., voice application) on AP/host 314, the Layer 2 layers, and the PHY layers. The connection between AP/host 314 may be achieved through various communication link protocols, e.g., such as universal serial bus (USB), peripheral component interconnect express (PCIe), or proprietary connections, where uncertainties in the link delays are unavoidable and unpredictable.

[0047] AP/host 314 may host multiple IMS applications, e.g., such as Voice coder-decoder (codec) over the RTP/UDP/IP stack, and may also include other audio, video, or IIoT applications (not shown) whose sources may be from external connect! vity/network applications 316 (e.g., an external IMS source) connected to AP/host 314. External connect! vity/network applications 316 may have payloads encapsulated in IP/UDP/RTP layers. When RTP packets arrive at ROHC compressor 310a, the arrival times of these packets may include jitter delays associated with unpredictable link connection and network delays.

[0048] Once the RTP packets for a QoS flow arrive at ROHC compressor 310a, the ROHC protocol compresses the RTP packet’s IP/UDP/RTP header for this QoS flow via an associated ROHC context flow, and sends out the replaced compressed ROHC header and payload to the layers (PDCP, RLC, MAC) of DL DP subsystem 306a, and DL PHY subsystem 302a for transmission to the network. On the network side, the peer ROHC decompressor (not shown) for this ROHC context flow will decode the corresponding ROHC headers and decompress it back to the full IP header.

[0049] In the exemplary Timer-based ROHC procedure, ROHC compressor 310a may analyze the incoming IP/UDP/RTP headers for compression. These headers comprise static and semi-static fields, which never or seldom change or can be inferred, and hence there is no need to send these fields every time to the network-side decompressor. On the other hand, as shown in FIG. 7, there are three main dynamic changing fields that are the main targets for compression by the ROHC protocol. These targets include the RTP Sequence Number (SN), RTP TimeStamp (TS), and IP Identification (IPID) fields. The 32-bit TS field can be compressed effectively via the exemplary Timer-based TS ROHC technique, if there are unavoidable random packet jitter delays and multiple silent gaps in the interarrival times between RTP packets.

[0050] Using this exemplary technique, ROHC compressor 310a may select the minimum number of k bits with which to encode/compress the TS field so that the full jitter delay range is covered, thereby enabling the peer decompressor on the network-side to recover the full header successfully. To that end, ROHC compressor 310a may derive/calculate the optimal number of k bits according to the jitter statistics of the RTP packets in its WLSB history. ROHC compressor 310a may store the WLSB history to track the random variable distribution of the dynamic traffic jitter pattern. In addition, ROHC compressor 310a may use the QoS target requirement (e.g., packet delay, error rate, etc.) for each application flow to derive/calculate the confidence interval for compression success. In other words, if the QoS target confidence interval range ([Ymin, Ymax]) is well less than the full random jitter range, the number of k bits for compression can be as small as possible while still covering this QoS target range. This will allow baseband chip 300 to transmit bits more efficiently (e.g., since the number is reduced) and at a higher compression ratio, thereby reducing power consumption and the amount of transmission resources.

[0051] Referring to FIGs. 3 and 4, the voice codec of AP/host 314 may send an audio encoded packet to the RTP/UDP/IP layers. The RTP/UDP/IP layers may encode (at 403) the ender to generate an RTP packet, which may be sent to ROHC compressor 310a. ROHC compressor 310a may compress (at 304) the header of the RTP packet and attach (at 407) the compressed header to the RTP payload in an external double-data rate (DDR) memory (not shown). An example of the compressible fields in the header is depicted in FIG. 5. These fields may include the IP ID field, the SN field, and the TS field. FIG. 6 depicts an example TS compression using the exemplary Timer-based ROHC technique for selecting the optimal number of k bits according to QoS depicted in FIG. 6. ROHC compressor 310a may enqueue (at 409) the RTP packet with the compressed header in ROHC queue of UL DP subsystem 306b. The UL Layer 2 layers (e.g., cipher layer, packet data convergence protocol (PDCP) layer, radio link control (RLC) layer, media access control (MAC) layer) may process the RTP packet with the compressed header to generate a MACPDU for transmission over the air by UL PHY subsystem 302b.

[0052] Referring to FIGs. 3 and 7, the jitter statistics of RTP packet may be maintained by ROHC compressor 310a in its WLSB (window-based LSB) window history, where it tracks the random variable distribution of traffic jitter pattern dynamically. Note that the TS is manipulated in a scaled TS unit since, by default, most IMS applications are encoded in regular time strides. The scaled RTP TS (T’) may be calculated according to expressions ( 1 )-(4) shown below.

T S_S TRIDE = (TS_n - TS_n-l) (1);

TIME STRIDE = equivalent time interval of TS STRIDE (2);

TS OFFSET = (TS) mod(TS STRIDE) (3); and

TS SCALED (TJ = floor (TS/TS S TRIDE) (4), where TS_n is the TS of a first RTP packet, TS_n-l is the TS of a second RTP packet received contiguous from the first RTP packet, and T’ is the scaled TS.

[0053] Once T’ is calculated, ROHC compressor 310a may maintain the RTP packet’s TS (TJ) and arrival times (AJ) in the WLSB window history, regardless of whether it is compressed, sent to a base station, not compressed, or not sent. Using the WLSB window history, ROHC compressor 310a may derive/calcul ate jitter statistics, which may provide insights into the traffic jitter delay patterns.

[0054] For instance, the random variable, distance, captures the jitter difference between the current RTP packet and a specific RTP packet in the WLSB window history. If the TJ and AJ of TSJ correlate well with most of the WLSB window history data points, the median may be around 0.

[0055] Distance value calculations may include the bounded jitter range of the link channel between ROHC compressor 310a and the network-side ROHC decompressor, as well as the clock quantization error (e.g., +/- 2). The MaxJitterCD is the bounded jitter range of the link channel between the compressor and decompressor, which is in the order of 2-5ms depending on the UL channel conditions. With the distance values calculated, ROHC compressor 310a may derive/calcul ate the jitter statistics (e.g., distance, maximum distance (DistMax), minimum distance (DistMin) of the WLSB window history according to expressions (5)-(7), shown below.

Distance = { (T’_n - T’ J) - ((A_n - AJ) / TIME STRIDE) } +/- MaxJitterCD +/- 2 (5), where T’_n is the scaled TS of the current RTP packet, T’ J is the scaled TS of a previous RTP packet, A n is the arrival time of the current RTP packet, and AJ is the arrival time of the previous RTP packet. = Timestamp (Scaled).

DistMax = Max{ (TS’_n - TS’ J) - ((A_n - AJ)/TIME_S TRIDE) } + MaxJitterCD + 2 (6); and DistMin = Min{ (TS’ n - TS’ J) - ((A n - AJ)/TIME_S TRIDE) } - MaxJitterCD - 2 (7).

[0056] ROHC compressor 310a may calculate the above jitter statistics for every RTP data point in the WLSB window history when a new RTP packet is received. DistMax and DistMin indicate the worst case positive and negative deviations of the jitter between the current packet and the window values, respectively. The median distance indicates the main offset of the current RTP packet from the bulk of the RTP data points in the WLSB window history. These simple yet tedious mathematical calculations may be easily implemented as customized instructions in a custom processor at ROHC compressor 310a or ROHC uC 308a, leading to lightweight and efficient CPU cycles.

[0057] Referring to FIGs. 3 and 8, once the jitter statistics are derived/calculated, ROHC compressor 310a may identify the bounds of the target QoS confidence interval range [Ymin, Ymax], The key idea is that with different QoS flow requirements for different QoS flows, the required target range to represent the jitter variation can be customized dynamically according to the traffic jitter delay distribution. The goal is to then select the smallest number of k bits for TS’ compression within [Ymin, Ymax],

[0058] In the example depicted in FIG. 8, the probability distribution of the jitter distance random variable is mapped for each distance value, and an example target QoS confidence interval (S%) of 90% is needed. The target QoS confidence interval may be identified based on the packet error rate associated with the current RTP packet’ s QoS profile. The packet delay budget may also tune the bound limits of the target QoS confidence interval range. With the target QoS confidence interval range calculated, ROHC compressor 310a may eliminate the outliers from the dataset symmetrically from the DistMax and DistMin values, until the target QoS confidence interval S% is reached with the rest of the data set. In this way, the [Ymin, Ymax] values may be derived. From here, ROHC compressor 310a may select the smallest number of k bits to represent this covered range within 2^A(k)-l for the most efficient compression/transmission.

[0059] In some embodiments, the k bit interpretation interval range is from [-p, 2^A(k)-l-p], where p = 2^A(k- 1), and the jitter distance various symmetrically around 0, which is the majority of the cases where a normal distribution peaks at 0, e.g., namely, the current RTP packet’s jitter value is consistent with the bulk of the data points in the WLSB window history.

[0060] Referring to FIGs. 3 and 9, the probability distribution of the jitter distance random variable from the perspective of an outlier is shown, where a large offset peak from the data set is detected. To determine whether the current RTP packet is an outlier, ROHC compressor 310a may determine whether the median value of the current RTP packet’s [Ymin, Ymax] is outside of the last RTP packet’s [Ymin, Ymax], When this happens, the current RTP packet may be discarded from the target QoS confidence interval and transmission so that the number of k bits is not increased dramatically/unnecessarily. However, the jitter variables and [Ymin, Ymax] may be stored in the WLSB window history as a new data point.

[0061] If the packet is not an outlier, and if Ymin and Ymax grow outwards from the previous [Ymin, Ymax] of the target QoS confidence interval, the new [Ymin, Ymax] for the target QoS confidence interval becomes effective, because ROHC compressor 310a needs to capture the jitter range change for successful decompression within the target QoS confidence interval. If the Ymin and Ymax for the target QoS confidence interval grow inward, though desired for efficient compression, ROHC compressor 310a may evaluate this inward trend for some time before actually taking effect. This is because ROHC compressor 310a needs to wait until the networkside decompressor is sufficiently trained to successfully decompress the RTP header with the most recent jitter values and the smaller k bit range, which it uses for reference. Hence, a counter value and threshold may be checked before replacing the new smaller Ymin and Ymax for the target QoS confidence interval.

[0062] FIGs. 10 A- 10C are a flowchart of an exemplary method 1000 (referred to hereinafter as “method 1000”) of wireless communication, according to some aspects of the present disclosure. Method 1000 may be performed by an apparatus, e.g., such as user equipment 102, node 200, baseband chip 300, ROHC uC 308a, ROHC compressor 310a, LCP uC 308b, UL PHY subsystem 302b, just to name a few. Method 1000 may include steps 1002-1040 as described below. It is to be appreciated that some of the steps may be optional, and some of the steps may be performed simultaneously, or in a different order than shown in FIGs. 10A-10C.

[0063] Referring to FIG. 10, at 1002, the apparatus may decide to perform the exemplary Timer-based TS ROHC technique described herein. At 1004, the apparatus may derive/calculate the scaled TS (T’), e.g., using expressions (l)-(4) shown above. At 1006, the apparatus may derive/calculate jitter statistics. For example, at 1008, the apparatus may derive the distance, DistMax, and DistMin according to expressions (5)-(7) shown above. At 1010, the apparatus may determine whether all jitter statistic values in the entire WLSB window history data set have been calculated. If not, the operations may return to 1008. If so, the operations may move to 1012 in FIG. 10B.

[0064] Referring to FIG. 10B, at 1012, the apparatus may derive/calculate the target QoS confidence interval range. For example, at 1014, the apparatus may determine whether the median of [Ymin, Ymax] of the current RTP packet is outside of the [Ymin, Ymax] of the previous RTP packet. If yes, the operations move to 1016, where the apparatus discards the current RTP packet but may include it’s jitter statistics and [Ymin, Ymax] in the WLSB window history dataset. If no, the operations move to 1008, where the apparatus looks up the target QoS confidence interval (S%) associated with the current RTP packet’s QoS flow, eliminate outlies symmetrically from Ymin and Ymax, and find a new [Ymin, Ymax] for the target QoS confidence interval. At 1020, the apparatus may start from Ymax, then alternatively Ymin to symmetrically discard RTP packet data points from the target QoS confidence interval calculation. At 1022, the apparatus may determine whether a counter value of discarded RTP packets is greater than a counter threshold. If no, the operations return to 1020. If yes, the operations move to 1024, where the apparatus may determine whether the Ymax of the current RTP packet is greater than or equal to the Ymax of the previous RTP packet and whether the Ymin of the current RTP packet is less than or equal to the Ymin of the previous RTP packet. If yes, the operations move to 1030 in FIG. 10C. If no, the operations may move to 1026, where the apparatus may determine whether the number of “No’s” at 1024 is greater than a QoS interval reduction threshold. If yes, the reduction in [Ymin, Ymax] takes effect, and the Ymax counter and the Ymin counter at 1024 are reset. If no, the operations move to 1028, where the apparatus does not yet decrease [Ymin, Ymax] for the target QoS target interval. The operations may move from 1028 to 1030 in FIG. 10C.

[0065] Referring to FIG. 10C, at 1030, the apparatus may select the smallest number of k bits for TS’ compression within the [Ymin, Ymax] (also referred to herein as the “jitter variation target range”) of the target QoS confidence interval. For example, at 1032, the apparatus may select the smallest number of k bits for TS’ compression such that the interpretation interval = 2^A(k)-l covers [Ymin, Ymax], At 1034, the apparatus may determine whether Ymin is greater than p and Ymax is less than 2^A(k)-l-p, where p is equal to 2^A(k-l)-l. If no, the operations move to 1036, where the apparatus may increment k to the next supported number of bits in the allowed packet types. If yes, the operations move to 1038, where the apparatus adds the T’_n and A n values to the WLSB window history data set. Then, the apparatus may compress the RTP packet header to k bits.

[0066] In various aspects of the present disclosure, the functions described herein may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or encoded as instructions or code on a non-transitory computer-readable medium. Computer-readable media includes computer storage media. Storage media may be any available media that can be accessed by a computing device, such as node 200 in FIG. 2. By way of example, and not limitation, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, HDD, such as magnetic disk storage or other magnetic storage devices, Flash drive, SSD, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a processing system, such as a mobile device or a computer. Disk and disc, as used herein, includes CD, laser disc, optical disc, digital video disc (DVD), and floppy disk where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media. [0067] According to one aspect of the present disclosure, a wireless device is provided. The wireless device may include an application processor configured to generate an RTP packet with an RTP header that includes a TS field. The wireless device may include a DP subsystem with a ROHC uC. The ROHC uC may be configured to receive, from the application processor, the RTP packet with the RTP header including the TS field. The ROHC uC may be configured to identify a jitter delay associated with the RTP packet based at least in part on the TS field in the RTP header. The ROHC uC may be configured to perform a timer-based timestamp ROHC procedure to select a number of bits for compressing the RTP header, the number of bits covering less than a maximum jitter range associated with RTP -packet traffic. The ROHC uC may be configured to compress the RTP header to the number of bits selected by the timer-based timestamp ROHC procedure.

[0068] In some embodiments, to perform the timer-based timestamp ROHC procedure to compress the RTP header to a number of bits that covers less than the maximum jitter range associated with previous RTP packets, the ROHC uC may be configured to calculate windowbased jitter statistics associated with a WLSB history of RTP-packet traffic. In some embodiments, the WLSB history may dynamically track a random variable distribution of a jitter pattern of the RTP-packet traffic in a WLSB window. In some embodiments, the random variable distribution may be associated with a TS value and an arrival-time value for each RTP packet of the RTP- packet traffic.

[0069] In some embodiments, to calculate the jitter statistics associated with the RTP- packet traffic based on its WLSB history, the ROHC uC may be configured to calculate, for each data point in the WLSB window, a distance from the RTP packet and a previous RTP packet. In some embodiments, the distance may be associated with a jitter difference.

[0070] In some embodiments, the distance between the RTP packet and the previous RTP packet may be calculated based on a difference between a first scaled TS value associated with the RTP packet and a second scaled TS value associated with the previous RTP packet, a difference between a first arrival-time value associated with the RTP packet and a second arrival-time value associated with the previous RTP packet, a time stride value associated with a TS difference between a plurality of consecutive RTP packets in the WLSB window, and a bounded jitter range of a link channel between a ROHC compressor and a network-side ROHC decompressor.

[0071] In some embodiments, to calculate the jitter statistics associated with the RTP- packet traffic based on its WLSB history, the ROHC uC may be configured to identity a maximum distance statistic and a minimum distance statistic based on the distance from the RTP packet to each data point in the WLSB window. In some embodiments, the maximum distance statistic may be calculated based on a difference between a first TS value associated with the RTP packet and a second TS value associated with a second RTP packet that is a maximum distance from the first TS value, a difference between a first arrival-time value associated with the RTP packet and a second arrival -time value associated with the second RTP packet that is a maximum distance from the first arrival-time value, the time stride value associated with the TS difference between the plurality of consecutive RTP packets in the WLSB window, and the bounded jitter range of the link channel between a ROHC compressor and a network-side ROHC decompressor. In some embodiments, the minimum distance statistic may be calculated for each data point in the WLSB window based on a difference between the first TS value associated with the RTP packet and a third TS value associated with a third RTP packet that is a minimum distance from the first TS value, a difference between the first arrival-time value associated with the RTP packet and a third arrival-time value associated with the third RTP packet that is a minimum distance from the first arrival-time value, the time stride value associated with the TS difference between the plurality of consecutive RTP packets in the WLSB window, and the bounded jitter range of the link channel between the ROHC compressor and the network-side ROHC decompressor..

[0072] In some embodiments, to perform the timer-based timestamp ROHC procedure to compress the RTP header to a number of bits that covers less than the maximum jitter range associated with previous RTP packets, the ROHC uC may be configured to calculate a QoS confidence interval range based on the WLSB history and the jitter statistics associated with the RTP packet. In some embodiments, the jitter statistics may include the maximum distance statistic and the minimum distance statistic.

[0073] In some embodiments, to perform the timer-based timestamp ROHC procedure to select the number of bits for compressing the RTP header, the ROHC uC may be configured to generate a probability distribution based on the random variable distribution of the jitter pattern of the RTP-packet traffic in the WLSB window, a maximum distance value for each RTP packet in the WLSB window, and a minimum distance value for each RTP packet in the WLSB window. In some embodiments, to perform the timer-based timestamp ROHC procedure to select the number of bits for compressing the RTP header, the ROHC uC may be configured to identify a jitter variation target range within the probability distribution based on a QoS profile of the RTP packet. In some embodiments, the number of bits for compressing the RTP header may be selected based on the jitter variation target range within the probability distribution.

[0074] In some embodiments, to perform the timer-based timestamp ROHC procedure to select the number of bits for compressing the RTP header, the ROHC uC may be configured to generate a probability distribution based on the random variable distribution of the jitter pattern of the RTP-packet traffic in the WLSB window, the maximum distance value for each RTP packet in the WLSB window, and the minimum distance value for each RTP packet in the WLSB window. In some embodiments, to perform the timer-based timestamp ROHC procedure to select the number of bits for compressing the RTP header, the ROHC uC may be configured to identify a median value of the probability distribution. In some embodiments, to perform the timer-based timestamp ROHC procedure to select the number of bits for compressing the RTP header, the ROHC uC may be configured to, in response to determining that the QoS confidence interval range including the jitter statistics of the RTP packet is outside of a previous QoS confidence interval range associated with a previous RTP packet, eliminate the jitter statistics of the RTP packet from the QoS confidence interval range. In some embodiments, to perform the timer-based timestamp ROHC procedure to select the number of bits for compressing the RTP header, the ROHC uC may be configured to, in response to determining that the QoS confidence interval range including the jitter statistics of the RTP packet is within the previous QoS confidence interval range associated with the previous RTP packet, include the jitter statistics of the RTP packet from the QoS confidence interval range. In some embodiments, the number of bits for compressing the RTP header may be selected based on the QoS confidence interval range within the probability distribution.

[0075] According to another aspect of the present disclosure, an apparatus for wireless communication of a UE is provided. The apparatus may include a wireless device. The wireless device may include an application processor configured to generate an RTP packet with an RTP header that includes a TS field. The wireless device may include a DP subsystem with a ROHC uC. The ROHC uC may be configured to receive, from the application processor, the RTP packet with the RTP header including the TS field. The ROHC uC may be configured to identify a jitter delay associated with the RTP packet based at least in part on the TS field in the RTP header. The ROHC uC may be configured to perform a timer-based timestamp ROHC procedure to select a number of bits for compressing the RTP header, the number of bits covering less than a maximum jitter range associated with RTP-packet traffic. The ROHC uC may be configured to compress the RTP header to the number of bits selected by the timer-based timestamp ROHC procedure.

[0076] In some embodiments, to perform the timer-based timestamp ROHC procedure to compress the RTP header to a number of bits that covers less than the maximum jitter range associated with previous RTP packets, the ROHC uC may be configured to calculate windowbased jitter statistics associated with a WLSB history of RTP-packet traffic. In some embodiments, the WLSB history may dynamically track a random variable distribution of a jitter pattern of the RTP-packet traffic in a WLSB window. In some embodiments, the random variable distribution may be associated with a TS value and an arrival-time value for each RTP packet of the RTP- packet traffic.

[0077] In some embodiments, to calculate the jitter statistics associated with the RTP- packet traffic based on its WLSB history, the ROHC uC may be configured to calculate, for each data point in the WLSB window, a distance from the RTP packet and a previous RTP packet. In some embodiments, the distance may be associated with a jitter difference.

[0078] In some embodiments, the distance between the RTP packet and the previous RTP packet may be calculated based on a difference between a first scaled TS value associated with the RTP packet and a second scaled TS value associated with the previous RTP packet, a difference between a first arrival-time value associated with the RTP packet and a second arrival-time value associated with the previous RTP packet, a time stride value associated with a TS difference between a plurality of consecutive RTP packets in the WLSB window, and a bounded jitter range of a link channel between a ROHC compressor and a network-side ROHC decompressor.

[0079] In some embodiments, to calculate the jitter statistics associated with the RTP- packet traffic based on its WLSB history, the ROHC uC may be configured to identity a maximum distance statistic and a minimum distance statistic based on the distance from the RTP packet to each data point in the WLSB window. In some embodiments, the maximum distance statistic may be calculated based on a difference between a first TS value associated with the RTP packet and a second TS value associated with a second RTP packet that is a maximum distance from the first TS value, a difference between a first arrival-time value associated with the RTP packet and a second arrival -time value associated with the second RTP packet that is a maximum distance from the first arrival-time value, the time stride value associated with the TS difference between the plurality of consecutive RTP packets in the WLSB window, and the bounded jitter range of the link channel between the ROHC compressor and the network-side ROHC decompressor. In some embodiments, the minimum distance statistic may be calculated for each data point in the WLSB window based on a difference between the first TS value associated with the RTP packet and a third TS value associated with a third RTP packet that is a minimum distance from the first TS value, a difference between the first arrival-time value associated with the RTP packet and a third arrival-time value associated with the third RTP packet that is a minimum distance from the first arrival-time value, the time stride value associated with the TS difference between the plurality of consecutive RTP packets in the WLSB window, and the bounded jitter range of the link channel between the ROHC compressor and the network-side ROHC decompressor.

[0080] In some embodiments, to perform the timer-based timestamp ROHC procedure to compress the RTP header to a number of bits that covers less than the maximum jitter range associated with previous RTP packets, the ROHC uC may be configured to calculate a QoS confidence interval range based on the WLSB history and the jitter statistics associated with the RTP packet. In some embodiments, the jitter statistics may include the maximum distance statistic and the minimum distance statistic.

[0081] In some embodiments,, to perform the timer-based timestamp ROHC procedure to select the number of bits for compressing the RTP header, the ROHC uC may be configured to generate a probability distribution based on the random variable distribution of the jitter pattern of the RTP-packet traffic in the WLSB window, a maximum distance value for each RTP packet in the WLSB window, and a minimum distance value for each RTP packet in the WLSB window. In some embodiments, to perform the timer-based timestamp ROHC procedure to select the number of bits for compressing the RTP header, the ROHC uC may be configured to identify a jitter variation target range within the probability distribution based on a QoS profile of the RTP packet. In some embodiments, the number of bits for compressing the RTP header may be selected based on the jitter variation target range within the probability distribution. [0082] In some embodiments, to perform the timer-based timestamp ROHC procedure to select the number of bits for compressing the RTP header, the ROHC uC may be configured to generate a probability distribution based on the random variable distribution of the jitter pattern of the RTP -packet traffic in the WLSB window, the maximum distance value for each RTP packet in the WLSB window, and the minimum distance value for each RTP packet in the WLSB window. In some embodiments, to perform the timer-based timestamp ROHC procedure to select the number of bits for compressing the RTP header, the ROHC uC may be configured to identify a median value of the probability distribution. In some embodiments, to perform the timer-based timestamp ROHC procedure to select the number of bits for compressing the RTP header, the ROHC uC may be configured to, in response to determining that the QoS confidence interval range including the jitter statistics of the RTP packet is outside of a previous QoS confidence interval range associated with a previous RTP packet, eliminate the jitter statistics of the RTP packet from the QoS confidence interval range. In some embodiments, to perform the timer-based timestamp ROHC procedure to select the number of bits for compressing the RTP header, the ROHC uC may be configured to, in response to determining that the QoS confidence interval range including the jitter statistics of the RTP packet is within the previous QoS confidence interval range associated with the previous RTP packet, include the jitter statistics of the RTP packet from the QoS confidence interval range. In some embodiments, the number of bits for compressing the RTP header may be selected based on the QoS confidence interval range within the probability distribution.

[0083] According to yet another aspect of the present disclosure, a method of wireless communication of a wireless device is provided. The method may include generating, by an application processor, an RTP packet with an RTP header that includes a TS field. The method may include receiving, by a ROHC uC of a DP subsystem, the RTP packet with the RTP header including the TS field from the application processor. The method may include identifying, by the ROHC uC of the DL DP subsystem, a jitter delay associated with the RTP packet based at least in part on the TS field in the RTP header. The method may include performing, by the ROHC uC of the DL DP subsystem, a timer-based timestamp ROHC procedure to select a number of bits for compressing the RTP header, the number of bits covering less than a maximum jitter range associated with RTP-packet traffic. The method may include compressing, by the ROHC uC of the DL DP subsystem, the RTP header to the number of bits selected by the timer-based timestamp ROHC procedure. [0084] In some embodiments, the performing, by the ROHC uC of the DL DP subsystem, the timer-based timestamp ROHC procedure to compress the RTP header to a number of bits that covers less than the maximum jitter range associated with previous RTP packets may include calculating jitter statistics associated with a WLSB history of RTP-packet traffic. In some embodiments, the WLSB history may dynamically track a random variable distribution of a jitter pattern of the RTP-packet traffic in a WLSB window. In some embodiments, the random variable distribution may be associated with a TS value and an arrival-time value for each RTP packet of the RTP-packet traffic. In some embodiments, the calculating the jitter statistics associated with the RTP-packet traffic based on its WLSB history may include calculating, for each data point in the WLSB window, a distance from the RTP packet and a previous RTP packet, the distance being associated with a jitter difference. In some embodiments, the distance between the RTP packet and the previous RTP packet may be calculated based on a difference between a first scaled TS value associated with the RTP packet and a second scaled TS value associated with the previous RTP packet, a difference between a first arrival-time value associated with the RTP packet and a second arrival-time value associated with the previous RTP packet, a time stride value associated with a TS difference between a plurality of consecutive RTP packets in the WLSB window, and a bounded jitter range of a link channel between a ROHC compressor and a network-side ROHC decompressor. In some embodiments, the calculating the jitter statistics associated with the RTP- packet traffic based on its WLSB history may include identifying a maximum distance statistic and a minimum distance statistic based on the distance from the RTP packet to each data point in the WLSB window. In some embodiments, the maximum distance statistic may be calculated based on a difference between a first TS value associated with the RTP packet and a second TS value associated with a second RTP packet that is a maximum distance from the first TS value, a difference between a first arrival-time value associated with the RTP packet and a second arrivaltime value associated with the second RTP packet that is a maximum distance from the first arrivaltime value, the time stride value associated with the TS difference between the plurality of consecutive RTP packets in the WLSB window, and the bounded jitter range of the link channel between the ROHC compressor and the network-side ROHC decompressor. In some embodiments, the minimum distance statistic may be calculated for each data point in the WLSB window based on a difference between the first TS value associated with the RTP packet and a third TS value associated with a third RTP packet that is a minimum distance from the first TS value, a difference between the first arrival-time value associated with the RTP packet and a third arrival-time value associated with the third RTP packet that is a minimum distance from the first arrival-time value, the time stride value associated with the TS difference between the plurality of consecutive RTP packets in the WLSB window, and the bounded jitter range of the link channel between the ROHC compressor and the network-side ROHC decompressor.

[0085] In some embodiments, the performing the timer-based timestamp ROHC procedure to compress the RTP header to a number of bits that covers less than the maximum jitter range associated with previous RTP packets may include calculating a QoS confidence interval range based on the WLSB history and the jitter statistics associated with the RTP packet. In some embodiments, the jitter statistics may include the maximum distance statistic and the minimum distance statistic.

[0086] In some embodiments, the performing the timer-based timestamp ROHC procedure to select the number of bits for compressing the RTP header may include generating a probability distribution based on the random variable distribution of the jitter pattern of the RTP-packet traffic in the WLSB window, a maximum distance value for each RTP packet in the WLSB window, and a minimum distance value for each RTP packet in the WLSB window. In some embodiments, the performing the timer-based timestamp ROHC procedure to select the number of bits for compressing the RTP header may include identifying a jitter variation target range within the probability distribution based on a QoS profile of the RTP packet. In some embodiments, the number of bits for compressing the RTP header may be selected based on the jitter variation target range within the probability distribution.

[0087] In some embodiments, the performing the timer-based timestamp ROHC procedure to select the number of bits for compressing the RTP header may include generating a probability distribution based on the random variable distribution of the jitter pattern of the RTP-packet traffic in the WLSB window, the maximum distance value for each RTP packet in the WLSB window, and the minimum distance value for each RTP packet in the WLSB window. In some embodiments, the performing the timer-based timestamp ROHC procedure to select the number of bits for compressing the RTP header may include identifying a median value of the probability distribution. In some embodiments, the performing the timer-based timestamp ROHC procedure to select the number of bits for compressing the RTP header may include, in response to determining that the QoS confidence interval range including the jitter statistics of the RTP packet is outside of a previous QoS confidence interval range associated with a previous RTP packet, the method further comprises eliminating the jitter statistics of the RTP packet from the QoS confidence interval range. In some embodiments, the performing the timer-based timestamp ROHC procedure to select the number of bits for compressing the RTP header may include, in response to determining that the QoS confidence interval range including the jitter statistics of the RTP packet is within the previous QoS confidence interval range associated with the previous RTP packet, the method further comprises including the jitter statistics of the RTP packet from the QoS confidence interval range. In some embodiments, the number of bits for compressing the RTP header may be selected based on the QoS confidence interval range within the probability distribution.

[0088] The foregoing description of the specific embodiments will so reveal the general nature of the present disclosure that others can, by applying knowledge within the skill of the art, readily modify and/or adapt for various applications such specific embodiments, without undue experimentation, without departing from the general concept of the present disclosure. Therefore, such adaptations and modifications are intended to be within the meaning and range of equivalents of the disclosed embodiments, based on the teaching and guidance presented herein. It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by the skilled artisan in light of the teachings and guidance.

[0089] Embodiments of the present disclosure have been described above with the aid of functional building blocks illustrating the implementation of specified functions and relationships thereof. The boundaries of these functional building blocks have been arbitrarily defined herein for the convenience of the description. Alternate boundaries can be defined so long as the specified functions and relationships thereof are appropriately performed.

[0090] The Summary and Abstract sections may set forth one or more but not all exemplary embodiments of the present disclosure as contemplated by the inventor(s), and thus, are not intended to limit the present disclosure and the appended claims in any way.

[0091] Various functional blocks, modules, and steps are disclosed above. The particular arrangements provided are illustrative and without limitation. Accordingly, the functional blocks, modules, and steps may be re-ordered or combined in different ways than in the examples provided above. Likewise, certain embodiments include only a subset of the functional blocks, modules, and steps, and any such subset is permitted. The breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

Claims

WHAT IS CLAIMED IS:

1. A wireless device, comprising: an application processor configured to: generate a real-time transport protocol (RTP) packet with an RTP header that includes a timestamp (TS) field; and a dataplane (DP) subsystem, comprising: a robust header compression (ROHC) microcontroller (uC) configured to: receive, from the application processor, the RTP packet with the RTP header including the TS field; identify a jitter delay associated with the RTP packet based at least in part on the TS field in the RTP header; perform a timer-based timestamp ROHC procedure to select a number of bits for compressing the RTP header, the number of bits covering less than a maximum jitter range associated with RTP-packet traffic; and compress the RTP header to the number of bits selected by the timer-based timestamp ROHC procedure.

2. The wireless device of claim 1, wherein, to perform the timer-based timestamp ROHC procedure to compress the RTP header to a number of bits that covers less than the maximum jitter range associated with previous RTP packets, the ROHC uC is configured to: calculate jitter statistics associated with a window-based least significant bits (LSB) (WLSB) history of RTP-packet traffic, wherein the WLSB history dynamically tracks a random variable distribution of a jitter pattern of the RTP-packet traffic in a WLSB window, and wherein the random variable distribution is associated with a TS value and an arrival-time value for each RTP packet of the RTP-packet traffic.

3. The wireless device of claim 2, wherein, to calculate the jitter statistics associated with the RTP-packet traffic based on its WLSB history, the ROHC uC is configured to: calculate, for each data point in the WLSB window, a distance from the RTP packet and a previous RTP packet, wherein the distance is associated with a jitter difference.

4. The wireless device of claim 3, wherein the distance from the RTP packet and the previous RTP packet is calculated based on a difference between a first scaled TS value associated with the RTP packet and a second scaled TS value associated with the previous RTP packet, a difference between a first arrival-time value associated with the RTP packet and a second arrival-time value associated with the previous RTP packet, a time stride value associated with a TS difference between a plurality of consecutive RTP packets in the WLSB window, and a bounded jitter range of a link channel between a ROHC compressor and a network-side ROHC decompressor.

5. The wireless device of claim 4, wherein, to calculate the jitter statistics associated with the RTP-packet traffic based on its WLSB history, the ROHC uC is configured to: identity a maximum distance statistic and a minimum distance statistic based on the distance from the RTP packet to each data point in the WLSB window, wherein the maximum distance statistic is calculated based on a difference between a first TS value associated with the RTP packet and a second TS value associated with a second RTP packet that is a maximum distance from the first TS value, a difference between a first arrival-time value associated with the RTP packet and a second arrival-time value associated with the second RTP packet that is a maximum distance from the first arrival-time value, the time stride value associated with the TS difference between the plurality of consecutive RTP packets in the WLSB window, and the bounded jitter range of the link channel between the ROHC compressor and the network-side ROHC decompressor, and wherein the minimum distance statistic is calculated for each data point in the WLSB window based on a difference between the first TS value associated with the RTP packet and a third TS value associated with a third RTP packet that is a minimum distance from the first TS value, a difference between the first arrival-time value associated with the RTP packet and a third arrival-time value associated with the third RTP packet that is a minimum distance from the first arrival-time value, the time stride value associated with the TS difference between the plurality of consecutive RTP packets in the WLSB window, and the bounded jitter range of the link channel between the ROHC compressor and the network-side ROHC decompressor.

6. The wireless device of claim 5, wherein, to perform the timer-based timestamp ROHC procedure to compress the RTP header to a number of bits that covers less than the maximum jitter range associated with previous RTP packets, the ROHC uC is configured to: calculate a quality-of-service (QoS) confidence interval range based on the WLSB history and the jitter statistics associated with the RTP packet, wherein the jitter statistics include the maximum distance statistic and the minimum distance statistic.

7. The wireless device of claim 6, wherein, to perform the timer-based timestamp ROHC procedure to select the number of bits for compressing the RTP header, the ROHC uC is configured to: generate a probability distribution based on the random variable distribution of the jitter pattern of the RTP -packet traffic in the WLSB window, a maximum distance value for each RTP packet in the WLSB window, and a minimum distance value for each RTP packet in the WLSB window; and identify a jitter variation target range within the probability distribution based on a QoS profile of the RTP packet, wherein the number of bits for compressing the RTP header is selected based on the jitter variation target range within the probability distribution.

8. The wireless device of claim 6, wherein, to perform the timer-based timestamp ROHC procedure to select the number of bits for compressing the RTP header, the ROHC uC is configured to: generate a probability distribution based on the random variable distribution of the jitter pattern of the RTP-packet traffic in the WLSB window, the maximum distance value for each RTP packet in the WLSB window, and the minimum distance value for each RTP packet in the WLSB window; identify a median value of the probability distribution; in response to determining that the QoS confidence interval range including the jitter statistics of the RTP packet is outside of a previous QoS confidence interval range associated with a previous RTP packet, eliminate the jitter statistics of the RTP packet from the QoS confidence interval range; and in response to determining that the QoS confidence interval range including the jitter statistics of the RTP packet is within the previous QoS confidence interval range associated with the previous RTP packet, include the jitter statistics of the RTP packet from the QoS confidence interval range, wherein the number of bits for compressing the RTP header is selected based on the QoS confidence interval range within the probability distribution.

9. An apparatus for wireless communication of a user equipment (UE), comprising: a baseband chip, comprising: an application processor configured to: generate a real-time transport protocol (RTP) packet with an RTP header that includes a timestamp (TS) field; and a dataplane (DP) subsystem, comprising: a robust header compression (ROHC) microcontroller (uC) configured to: receive, from the application processor, the RTP packet with the

RTP header including the TS field; identify a jitter delay associated with the RTP packet based at least in part on the TS field in the RTP header; perform a timer-based timestamp ROHC procedure to select a number of bits for compressing the RTP header, the number of bits covering less than a maximum jitter range associated with RTP-packet traffic; and compress the RTP header to the number of bits selected by the timerbased timestamp ROHC procedure.

10. The apparatus of claim 9, wherein, to perform the timer-based timestamp ROHC procedure to compress the RTP header to a number of bits that covers less than the maximum jitter range associated with previous RTP packets, the ROHC uC is configured to: calculate jitter statistics associated with a window-based least significant bits (LSB) (WLSB) history of RTP-packet traffic, wherein the WLSB history dynamically tracks a random variable distribution of a jitter pattern of the RTP-packet traffic in a WLSB window, and wherein the random variable distribution is associated with a TS value and an arrival-time value for each RTP packet of the RTP -packet traffic.

11. The apparatus of claim 10, wherein, to calculate the jitter statistics associated with the RTP- packet traffic based on its WLSB history, the ROHC uC is configured to: calculate, for each data point in the WLSB window, a distance from the RTP packet and a previous RTP packet, wherein the distance is associated with a jitter difference.

12. The apparatus of claim 11, wherein the distance from the RTP packet and the previous RTP packet is calculated based on a difference between a first scaled TS value associated with the RTP packet and a second scaled TS value associated with the previous RTP packet, a difference between a first arrival-time value associated with the RTP packet and a second arrival -time value associated with the previous RTP packet, a time stride value associated with a TS difference between a plurality of consecutive RTP packets in the WLSB window, and a bounded jitter range of a link channel between a ROHC compressor and a network-side ROHC decompressor.

13. The apparatus of claim 12, wherein, to calculate the jitter statistics associated with the RTP- packet traffic based on its WLSB history, the ROHC uC is configured to: identity a maximum distance statistic and a minimum distance statistic based on the distance from the RTP packet to each data point in the WLSB window, wherein the maximum distance statistic is calculated based on a difference between a first TS value associated with the RTP packet and a second TS value associated with a second RTP packet that is a maximum distance from the first TS value, a difference between a first arrival-time value associated with the RTP packet and a second arrival-time value associated with the second RTP packet that is a maximum distance from the first arrival-time value, the time stride value associated with the TS difference between the plurality of consecutive RTP packets in the WLSB window, and the bounded jitter range of the link channel between the ROHC compressor and the network-side ROHC decompressor, and wherein the minimum distance statistic is calculated for each data point in the WLSB window based on a difference between the first TS value associated with the RTP packet and a third TS value associated with a third RTP packet that is a minimum distance from the first TS value, a difference between the first arrival-time value associated with the RTP packet and a third arrival-time value associated with the third RTP packet that is a minimum distance from the first arrival-time value, the time stride value associated with the TS difference between the plurality of consecutive RTP packets in the WLSB window, and the bounded jitter range of the link channel between the ROHC compressor and the network-side ROHC decompressor.

14. The apparatus of claim 13, wherein, to perform the timer-based timestamp ROHC procedure to compress the RTP header to a number of bits that covers less than the maximum jitter range associated with previous RTP packets, the ROHC uC is configured to: calculate a quality-of-service (QoS) confidence interval range based on the WLSB history and the jitter statistics associated with the RTP packet, wherein the jitter statistics include the maximum distance statistic and the minimum distance statistic.

15. The apparatus of claim 14, wherein, to perform the timer-based timestamp ROHC procedure to select the number of bits for compressing the RTP header, the ROHC uC is configured to: generate a probability distribution based on the random variable distribution of the jitter pattern of the RTP -packet traffic in the WLSB window, a maximum distance value for each RTP packet in the WLSB window, and a minimum distance value for each RTP packet in the WLSB window; and identify a jitter variation target range within the probability distribution based on a QoS profile of the RTP packet, wherein the number of bits for compressing the RTP header is selected based on the jitter variation target range within the probability distribution.

16. The apparatus of claim 15, wherein, to perform the timer-based timestamp ROHC procedure to select the number of bits for compressing the RTP header, the ROHC uC is configured to: generate a probability distribution based on the random variable distribution of the jitter pattern of the RTP-packet traffic in the WLSB window, the maximum distance value for each RTP packet in the WLSB window, and the minimum distance value for each RTP packet in the WLSB window; identify a median value of the probability distribution; in response to determining that the QoS confidence interval range including the jitter statistics of the RTP packet is outside of a previous QoS confidence interval range associated with a previous RTP packet, eliminate the jitter statistics of the RTP packet from the QoS confidence interval range; and in response to determining that the QoS confidence interval range including the jitter statistics of the RTP packet is within the previous QoS confidence interval range associated with the previous RTP packet, include the jitter statistics of the RTP packet from the QoS confidence interval range, wherein the number of bits for compressing the RTP header are selected based on the QoS confidence interval range within the probability distribution.

17. A method of wireless communication of a wireless device, comprising: generating, by an application processor, a real-time transport protocol (RTP) packet with an RTP header that includes a timestamp (TS) field; receiving, by a robust header compression (ROHC) microcontroller (uC) of a dataplane (DP) subsystem, the RTP packet with the RTP header including the TS field from the application processor; identifying, by the ROHC uC of the DP subsystem, a jitter delay associated with the RTP packet based at least in part on the TS field in the RTP header; and performing, by the ROHC uC of the DP subsystem, a timer-based timestamp ROHC procedure to select a number of bits for compressing the RTP header, the number of bits covering less than a maximum jitter range associated with RTP-packet traffic; and compressing, by the ROHC uC of the DP subsystem, the RTP header to the number of bits selected by the timer-based timestamp ROHC procedure.

18. The method of claim 17, wherein the performing, by the ROHC uC of the DP subsystem, the timer-based timestamp ROHC procedure to compress the RTP header to a number of bits that covers less than the maximum jitter range associated with previous RTP packets comprises: calculating jitter statistics associated with a window-based least significant bits (LSB) (WLSB) history of RTP-packet traffic, wherein the WLSB history dynamically tracks a random variable distribution of a jitter pattern of the RTP-packet traffic in a WLSB window, and wherein the random variable distribution is associated with a TS value and an arrival-time value for each RTP packet of the RTP-packet traffic, and wherein the calculating the jitter statistics associated with the RTP-packet traffic based on its WLSB history comprises: calculating, for each data point in the WLSB window, a distance from the RTP packet and a previous RTP packet, the distance being associated with a jitter difference, wherein the distance from the RTP packet and the previous RTP packet is calculated based on a difference between a first scaled TS value associated with the RTP packet and a second scaled TS value associated with the previous RTP packet, a difference between a first arrival-time value associated with the RTP packet and a second arrival-time value associated with the previous RTP packet, a time stride value associated with a TS difference between a plurality of consecutive RTP packets in the WLSB window, and a bounded jitter range of a link channel between a ROHC compressor and a network-side ROHC decompressor, wherein the calculating the jitter statistics associated with the RTP-packet traffic based on its WLSB history comprises: identifying a maximum distance statistic and a minimum distance statistic based on the distance from the RTP packet to each data point in the WLSB window, wherein the maximum distance statistic is calculated based on a difference between a first TS value associated with the RTP packet and a second TS value associated with a second RTP packet that is a maximum distance from the first TS value, a difference between a first arrival-time value associated with the RTP packet and a second arrival-time value associated with the second RTP packet that is a maximum distance from the first arrival-time value, the time stride value associated with the TS difference between the plurality of consecutive RTP packets in the WLSB window, and the bounded jitter range of the link channel between the ROHC compressor and the network-side ROHC decompressor, and wherein the minimum distance statistic is calculated for each data point in the WLSB window based on a difference between the first TS value associated with the RTP packet and a third TS value associated with a third RTP packet that is a minimum distance from the first TS value, a difference between the first arrival-time value associated with the RTP packet and a third arrival-time value associated with the third RTP packet that is a minimum distance from the first arrival-time value, the time stride value associated with the TS difference between the plurality of consecutive RTP packets in the WLSB window, and the bounded jitter range of the link channel between the ROHC compressor and the network-side ROHC decompressor.

19. The method of claim 18, wherein the performing the timer-based timestamp ROHC procedure to compress the RTP header to a number of bits that covers less than the maximum jitter range associated with previous RTP packets comprises: calculating a quality-of-service (QoS) confidence interval range based on the WLSB history and the jitter statistics associated with the RTP packet, wherein the jitter statistics include the maximum distance statistic and the minimum distance statistic.

20. The method of claim 19, wherein: the performing the timer-based timestamp ROHC procedure to select the number of bits for compressing the RTP header comprises: generating a probability distribution based on the random variable distribution of the jitter pattern of the RTP -packet traffic in the WLSB window, a maximum distance value for each RTP packet in the WLSB window, and a minimum distance value for each RTP packet in the WLSB window; and identifying a jitter variation target range within the probability distribution based on a QoS profile of the RTP packet, wherein the number of bits for compressing the RTP header is selected based on the jitter variation target range within the probability distribution, or the performing the timer-based timestamp ROHC procedure to select the number of bits for compressing the RTP header comprises: generating a probability distribution based on the random variable distribution of the jitter pattern of the RTP-packet traffic in the WLSB window, the maximum distance value for each RTP packet in the WLSB window, and the minimum distance value for each RTP packet in the WLSB window; identifying a median value of the probability distribution; in response to determining that the QoS confidence interval range including the jitter statistics of the RTP packet is outside of a previous QoS confidence interval range associated with a previous RTP packet, the method further comprises eliminating the jitter statistics of the RTP packet from the QoS confidence interval range; and in response to determining that the QoS confidence interval range including the jitter statistics of the RTP packet is within the previous QoS confidence interval range associated with the previous RTP packet, the method further comprises including the jitter statistics of the RTP packet from the QoS confidence interval range, wherein the number of bits for compressing the RTP header are selected based on the QoS confidence interval range within the probability distribution.