Patent Description:
The present disclosure relates to communication systems, in particular, to techniques to provide link establishment between a radio equipment controller (REC) and radio equipment (RE) in a fronthaul network.

Mobile networking architectures have grown increasingly complex in communication environments. In particular, access network configurations for mobile networking architectures have become more complex. As access network configurations become more complex, facilitating communications among access network elements such as a radio equipment controller and radio equipment becomes more critical. Accordingly, there are significant challenges in facilitating communications between a radio equipment controller and radio equipment in a network.

<CIT> describes, according to its abstract, a protocol conversion method and device, used for implementing compatibility with traditional radio equipment (RE) for an Ethernet protocol-based network. The method comprises: a protocol conversion device receiving a first Ethernet message sent by a radio equipment controller (REC), the first Ethernet message carrying first common public radio interface (CPRI) data; and the protocol conversion device carrying out traffic shaping for the first CPRI data, and sending the first CPRI data to radio equipment (RE).

Provided herein are techniques associated with link establishment between a radio equipment controller (REC) and a radio equipment (RE) in a fronthaul network. Using techniques discussed for embodiments described herein, a network operator can deploy Common Public Radio Interface (CPRI)-based REC and RE of varied capabilities in a fronthaul network and the techniques discussed for embodiments herein can be used to achieve deterministic end-to-end CPRI link synchronization between the REC and RE.

In one embodiment, a computer-implemented method is provided and may include receiving, by a proxy node, a Common Public Radio Interface (CPRI) bit stream transmitted by a radio equipment controller, wherein the CPRI bit stream is transmitted within a transmit time interval of the radio equipment controller; and fast-sampling, by the proxy node, the CPRI bit stream to determine whether a hyper frame number synchronization with the radio equipment controller at a common matching link bit rate is achievable, wherein the fast-sampling comprises attempting to decode the received CPRI bit stream and achieve the hyper frame number synchronization for each of a plurality of link bit rates configured for a fast-sampling time period during at least one fast-sampling time interval configured for the proxy node.

In another embodiment, another computer implemented method is provided and may include performing, for one or more link bit rates of a plurality of link bit rates configured for a fronthaul network, Common Public Radio Interface (CPRI) Layer <NUM> link auto-negotiation operations to establish a CPRI link between a radio equipment controller and a radio equipment of the fronthaul network, the CPRI Layer <NUM> link auto-negotiation operations comprising: fast-sampling, by a proxy slave, a CPRI bit stream transmitted by a radio equipment controller to achieve a hyper frame number synchronization with the radio equipment controller at a matching link bit rate, wherein the fast-sampling comprises attempting to achieve the hyper frame number synchronization for each of a plurality of link bit rates configured for a fast-sampling time period during at least one fast-sampling time interval configured for the proxy slave. Upon the proxy slave achieving the hyper frame number synchronization with the radio equipment controller, the proxy slave starts transmitting the CPRI bit stream after mapping into RoE frames as per the matching link bit rate along with the matching link bit rate information in the RoE frame header from the proxy slave to a proxy master.

The proxy master begins transmitting the CPRI bit stream to the radio equipment immediately and the radio equipment attempts to achieve a hyper frame number synchronization. On achieving a hyper frame number synchronization with this proxy master transmitted stream which was originated at radio equipment controller, the radio equipment also starts playing out CPRI bit stream towards the proxy master at the same link bit rate; the proxy master transmits this received CPRI bit stream towards the proxy slave after mapping to RoE frames which is then played out as CPRI bit stream towards the radio equipment controller by the proxy slave. All this occurring within a fixed transmit time interval for a link bit rate on the radio equipment controller ensures the Layer <NUM> link auto-negotiation operations are completed and the CPRI link is established between the radio equipment controller and the radio equipment when the radio equipment controller achieves a hyper frame number synchronization for the CPRI bit stream transmitted by the proxy slave.

Techniques associated with link establishment in a fronthaul network are described herein. In one embodiment, a method includes receiving, by a proxy node, a Common Public Radio Interface (CPRI) bit stream transmitted by a radio equipment controller, wherein the CPRI bit stream is transmitted within a transmit time interval of the radio equipment controller; and fast-sampling, by the proxy node, the CPRI bit stream to determine whether a hyper frame number synchronization with the radio equipment controller at a common matching link bit rate is achievable, wherein the fast-sampling comprises attempting to decode the received CPRI bit stream and achieve the hyper frame number synchronization for each of a plurality of link bit rates configured for a fast-sampling time period during at least one fast-sampling time interval configured for the proxy node.

Communications in a network environment can be referred to herein as 'messages', 'messaging', 'signaling', 'data', 'content', 'objects', 'requests', 'queries', 'responses', 'replies', etc. which may be inclusive of packets. As referred to herein and in the claims, the term 'packet' may be used in a generic sense to include packets, frames, segments, datagrams, and/or other generic data units that may be used to transmit communications (e.g., data and/or commands) in a network. A packet is a formatted unit of data that can contain control or routing information (e.g., source and destination address, etc.) and data, which is also sometimes referred to as a payload or data payload. In some embodiments, control or routing information, management information, or the like can be included in packet fields, such as within header(s) and/or trailer(s) of packets.

The terms 'data', 'information', 'parameters,' and the like as used herein can refer to any type of binary, numeric, voice, video, textual or script data or information or any type of source or object code, or any other suitable data or information in any appropriate format that can be communicated from one point to another in electronic devices and/or networks. Additionally, messages, requests, responses, replies, queries, etc. are forms of network traffic and, therefore, may comprise one or more packets.

Communications in a network environment can be sent and received according to any suitable communication protocols. Suitable communication protocols can include a multi-layered scheme such as the Open Systems Interconnection (OSI) Model, or any derivations or variants thereof. Internet Protocol (IP) addresses discussed herein and in the claims can include IP version <NUM> (IPv4) and/or IP version <NUM> (IPv6) addresses. For example, various Layer <NUM> (L1) and/or Layer <NUM> (L2) communications/operations may be referenced herein.

Architectures that facilitate network communications generally rely upon three basic components: a data or user plane, a control plane, and a management plane. Typically, the user plane carries data traffic (e.g., user data traffic), while the control plane and the management plane serve the data plane. As referred to herein and in the claims, the term 'plane' can refer to a separation of traffic, operations, etc. for a network and/or network element or node.

In general, 3rd Generation Partnership Project (3GPP) mobile network architectures such as 3GPP Long Term Evolution (LTE) architectures, sometimes referred to as 4th Generation (<NUM>)/LTE architectures, as well as 3GPP 5th Generation (<NUM>) architectures can be implemented via a core network and one or more 3GPP access networks in which user equipment (UEs) connect to a core network via over-the-air Radio Frequency (RF) communications with radio units or radio equipment (RE) of the access networks. Some 3GPP access networks can be implemented in a configuration that includes a radio equipment controller (REC) that interfaces with the core network and also that interfaces with one or more RE. In some instances, an REC may also be referred to as a Baseband Unit (BBU) and an RE may be referred to as a Remote Radio Head (RRH). Both the REC and RE are two basic building blocks of a radio base station. The REC is concerned with the Network Interface transport, the radio base station control and management as well as the digital baseband processing. The RE provides the analogue and radio frequency functions via a radio head such as filtering, modulation, frequency conversion and amplification or, more generally, RE serves as the air interface, to the user equipment.

In current deployments of co-located REC and RE, the Common Public Radio Interface (CPRI) is used as directly connected bi-directional point-to-point over fiber. In general, CPRI is a point to point bit synchronous serial data link between the co-located REC and the RE providing an 'always ON constant bit rate' steady data stream. As referred to herein, the terms 'data link' and 'link' can be used interchangeably.

Referring to <FIG> is a simplified diagram <NUM> illustrating example details associated with CPRI link bit rate negotiation. <FIG> illustrates the transmit link bit rates <NUM> for a CPRI bit stream transmitted by the master port (REC) and receive/decode link bit rates <NUM> at which a slave port (RE) attempts to receive and decode the master port (REC) transmitted CPRI bit stream in relation to times <NUM>(<NUM>)-<NUM>(<NUM>), as represented along a time axis <NUM>.

A CPRI link negotiation is performed to negotiate a common matching link bit rate for establishing the bi-directional CPRI data link between co-located REC and RE. <NPL>, describes the current procedure for link negotiation between REC and RE in direct connected deployments, in which the master port (REC) drives the link bring-up with the slave port (RE) and link bit rate auto negotiation, L1 synchronization, and frame synchronization/alignment all happen together directly between the co-located REC and RE. For CPRI Specification v7. <NUM>, bit rate is referred to as 'line bit rate'; however, for purposes of discussions herein, the term 'link bit rate' will be used. Further as referred to herein, the terms 'link auto-negotiation', 'link negotiation', and 'link bit-rate negotiation', may be used interchangeably. Further as referred to herein, the terms 'synchronization' and 'sync' may be used interchangeably.

CPRI L1 synchronization accomplishes two things between the master and slave ports: byte alignment and hyper frame alignment for CPRI bit streams transmitted via the data link between the co-located REC and RE at a common matching link bit rate for the master and slave. Following frame synchronization/alignment, negotiations associated with protocol setup and control and management (C&M) setup, also referred to as L2 negotiations, are performed to determine a highest common matching link bit rate for the master and slave (if not already selected during the L1 sync) and also to determine a CPRI (in-band) C&M channel bit rate, C&M protocol, and vendor specific negotiations/signaling.

The following procedure is used to arrive at a common matching link bit rate as per CPRI Specification v7.

The above <NUM> steps are repeated until a common link bit rate match is achieved between the co-located REC and RE. Per CPRI Specification v7. <NUM> Section <NUM>. <NUM>, the above steps/actions are associated with a start-up process that is implemented via a CPRI port state machine configured for the CPRI interface elements/ports of the REC and RE in which operations, events, and transitions through states of the CPRI port state machine are prescribed according to CPRI Specification v7.

Consider an example as illustrated in <FIG>. If the master port (REC) has a capability set in which it is capable of {<NUM>, <NUM>, <NUM>, and <NUM>} Gigabits per second (Gbps) CPRI link bit rates and the slave port (RE) is capable of {<NUM> and <NUM>} Gbps CPRI link bit rates, the following occurs:.

While the link negotiation procedure can be performed according CPRI Specification v7. <NUM> when the REC and RE are co-located and directly connected, the procedure cannot work in fronthaul networks in which the REC and RE are interconnected through one or more intermediate nodes via a packet-based network, such as an Ethernet network.

The presence of the intermediate nodes in a fronthaul network poses a discontinuity problem for establishing the CPRI link negotiation (e.g., comprising link bit rate negotiation, L1 synchronization, and frame synchronization/alignment) between the REC and RE using the process prescribed by CPRI Specification v7. In fronthaul networks, the REC and RE endpoints cannot communicate directly with each other due to presence of CPRI interfacing Ethernet nodes as all these nodes may be running at different rates. Without having a commonly understandable CPRI link bit rate across the entire CPRI path for the CPRI interfacing nodes, the end-to-end CPRI link negotiation cannot be achieved.

In a fronthaul network, the REC and RE do not interact directly; rather Ethernet nodes capable of CPRI mapping and de-mapping (e.g., mapping and de-mapping between a CPRI bit stream and Ethernet frames and vice-versa, depending on the direction of communications) interface with the REC and RE. The Ethernet node capable of CPRI mapping/de-mapping connected directly to the REC is referred to herein as a 'Proxy Slave' or a 'CPRI Proxy Slave' and the Ethernet node capable of CPRI mapping/de-mapping connected directly to the RE is referred to herein as a 'Proxy Master' or a 'CPRI Proxy Master'. The Proxy Master and the Proxy Slave nodes may be referred to generally as 'proxy nodes'.

In a typical fronthaul network, the Proxy Master and Proxy Slave can communicate over a packet-based network, such as an Ethernet network, using Radio over Ethernet (RoE) communications, as prescribed by the Institute of Electrical and Electronics Engineers (IEEE) <NUM> and IEEE <NUM> Specifications, approved September <NUM>, <NUM>. IEEE <NUM> and <NUM> (referred to herein as 'IEEE <NUM> standards') provide standards for encapsulation and mapping/de-mapping of radio data, such as CPRI bit streams, and/or potentially control and/or management packets within Ethernet frames. For a given Ethernet frame, radio data and/or potentially control and/or management packets can be included within a RoE frame that is encapsulated in the Ethernet frame. As discussed in further detail herein, a RoE frame can include an RoE header and an RoE payload.

The IEEE <NUM> standards define different RoE mappers/de-mappers, including: structure-aware, structure-agnostic, and native mode in which structure-aware mapping/de-mapping operations can be used for CPRI data, structure-agnostic mapping/de-mapping operations can be used for any digitized radio data, and native mode mapping/de-mapping operations can be used for digitized radio In-phase/Quadrature (I/Q) payload data.

The structure-agnostic RoE mapper is considered for embodiments described herein. While the IEEE <NUM> and IEEE <NUM> Specifications provide standards for encapsulation and mapping/de-mapping of CPRI bit streams over packet-based fronthaul transport networks, the standards do not cover how end-to-end link negotiations can be performed between an REC and RE in fronthaul networks.

Further, current CPRI link negotiation processes as prescribed by CPRI Specification v7. <NUM> will not work in fronthaul networks. Recall, the key points for end-to-end CPRI link negotiation as prescribed by CPRI Specification v7. <NUM> are:.

However, in a fronthaul network, when using current CPRI link negotiation processes as prescribed by CPRI Specification v7. <NUM>, the following can occur:.

One possible solution arriving at a common link rate on all nodes including the REC and RE in the CPRI path flow may be to use a manual static configuration at all CPRI endpoints and the intermediate CPRI interfacing nodes; however, such a solution is error prone, inefficient at times, and not scalable.

Example embodiments described herein provide techniques to overcome these hurdles by providing a mechanism to provide CPRI link establishment between an REC and an RE in an Ethernet-based fronthaul network. A CPRI link for a fronthaul network is a cross product of CPRI and Ethernet as the end-to-end nodes (REC/RE) use CPRI only to communicate with each other via the proxy nodes, which perform mapping/de-mapping and link monitoring operations. Thus, embodiments described herein may facilitate end-to-end CPRI link synchronization between an REC and an RE in which the REC represents one end and the RE represents another end of the end-to-end CPRI link synchronization.

Referring to <FIG> is a simplified diagram illustrating example details associated with a fronthaul network <NUM> in which techniques to provide link establishment between an REC <NUM> and RE <NUM> may be implemented, according to an example embodiment. <FIG> includes REC <NUM>, RE <NUM>, a Proxy Slave <NUM>, a Proxy Master <NUM>, and an Ethernet network <NUM>. As referred to herein, REC <NUM> may also be referred to as the 'CPRI Master' and RE <NUM> may be referred to as the 'CPRI Slave'. Further as referred to herein, fronthaul network <NUM> may also be referred to as an Ethernet-based fronthaul network <NUM>.

In at least one embodiment, at least one CPRI interface element/port may be configured for each of Proxy Slave <NUM> and Proxy Master <NUM> in which the CPRI port state machine may be configured for the CPRI interface element/port for each of Proxy Slave <NUM> and Proxy Master <NUM>. As discussed for embodiments herein, some operations of Proxy Slave <NUM> involving L1 link negotiations/sync with REC <NUM> may differ from the standard negotiation/sync processes as described by CPRI Specification v7. <NUM>, while other operations, such as updating internal states of the CPRI port state machine for REC <NUM> may follow the processes described by CPRI Specification v7. In at least one embodiment, at least one Ethernet interface element/port may also be configured for each of Proxy Slave <NUM> and Proxy Master <NUM> to facilitate communications via Ethernet network <NUM>.

As illustrated in <FIG>, the interconnection between REC <NUM> and Proxy Slave <NUM> is a CPRI interconnection, the interconnection between Proxy Slave <NUM> and Ethernet network <NUM> is an Ethernet interconnection, the interconnection between RE <NUM> and Proxy Master <NUM> is a CPRI interconnection, and the interconnection between Proxy Master <NUM> and Ethernet network <NUM> is an Ethernet interconnection. REC <NUM> may further interface with a 3GPP mobile core network (not shown).

Proxy Slave <NUM> is an Ethernet node connected directly to REC <NUM> and also to Ethernet network <NUM>. Proxy Slave <NUM> is capable of performing CPRI mapping and de-mapping for various communications/operations within fronthaul network <NUM>, as discussed herein. Proxy Master <NUM> is an Ethernet node connected directly to RE <NUM> and also to Ethernet network <NUM>. Proxy Master <NUM> is capable of performing CPRI mapping and de-mapping for various communications/operations, as discussed herein. Proxy Slave <NUM> and Proxy Master <NUM> may interface with each other using Ethernet-based communications using Ethernet network <NUM>.

RoE frames encapsulated within Ethernet frames may be utilized for communications of radio data to/from REC <NUM> and RE <NUM> in which Proxy Slave <NUM> and Proxy Master <NUM> can map/de-map CPRI bit streams to/from RoE frames for communications across Ethernet network <NUM> and with each of REC <NUM> and RE <NUM> (e.g., via the CPRI interconnection between Proxy Slave <NUM> and REC <NUM> and also via the CPRI interconnection between Proxy Master <NUM> and RE <NUM>) to facilitate end-to-end communications between REC <NUM> and RE <NUM>.

As noted above, the structure-agnostic RoE mapper is considered for embodiments described herein.

In at least one embodiment, as discussed in further detail herein, a RoE header of an RoE frame may be enhanced to include link bit rate information to facilitate end-to-end L1 link auto-negotiation operations and CPRI link establishment between REC <NUM> and RE <NUM> for fronthaul network <NUM>.

Referring to <FIG> is a simplified diagram <NUM> illustrating example details associated with fast-sampling a CPRI bit stream by a proxy node during link establishment operations, according to an example embodiment. Reference is also made to <FIG> in connection with the description of <FIG>.

For the embodiment of <FIG>, consider that REC <NUM> is configured with a capability set including link bit rates of {<NUM>, <NUM>, <NUM>, <NUM>} Gbps and Proxy Slave <NUM> is configured with a capability set including link bit rates of {<NUM>, <NUM>, <NUM>, <NUM>} Gbps. Example details illustrated in <FIG> are illustrated reference to time, represented by a time axis <NUM>. As illustrated in <FIG>, REC <NUM> transmits a CPRI bit stream at link bit rates <NUM> according to its capability set starting at <NUM>.

As per CPRI Specification v7. <NUM>, in a non-fronthaul deployment REC begins to transmit a CPRI bit stream at a given link bit rate for <NUM>-<NUM> seconds while the RE (slave) tries to receive and decode for <NUM>-<NUM> seconds and the procedure is repeated.

Embodiments herein, however, provide techniques for an enhanced procedure in which Proxy Slave <NUM> can achieve HFN sync within a shorter period of time than the procedure as prescribed per CPRI Specification v7. For example, embodiments herein provide that Proxy Slave <NUM> may perform oversampling or fast-sampling of a REC <NUM> transmitted CPRI bit stream multiple times using its own supported link rates starting with the highest rate, next highest rate, and so on, and then repeating the same starting with the highest rate until a common matching link bit rate is achieved for the REC <NUM> transmitted stream. Assuming a that a matching link bit rate is configured for Proxy Slave <NUM> and for REC <NUM>, this will result in achieving a link bit rate match between the REC and the Proxy Slave within a first complete fast-sampling time interval (<NUM>-<NUM> seconds) of the Proxy Slave.

As illustrated in <FIG>, Proxy Slave <NUM> attempts to receive and decode for one or more fast-sampling time periods <NUM> of a fast-sampling time interval <NUM> in which the fast-sampling time interval is set to <NUM>-<NUM> seconds in duration, which is based on the transmit time interval (<NUM>-<NUM> seconds) for REC <NUM>. For a particular fast-sampling time period <NUM>, Proxy Slave <NUM> switches between link bit rates of a link bit rate fast-sampling set <NUM>, which is configured with link bit rate values in an order that is based on the capability set configured for Proxy Slave <NUM>. For example, as illustrated in <FIG>, the link bit rate fast-sampling set <NUM> includes link bit rates <NUM> Gbps, <NUM> Gbps, <NUM> Gbps, and <NUM> Gbps in which the values and the order of the values are set to the same values and order of values of the capability set configured for Proxy Slave <NUM> for the embodiment of <FIG>.

In one iteration of the fast-sampling time period <NUM>, Proxy Slave <NUM> will use all of the configured rates of link bit rate fast-sampling set <NUM>, one by one, to attempt to receive and decode a CPRI bit stream transmitted by REC <NUM> (assuming the REC has begun transmissions). The number of iterations of fast-sampling periods time <NUM> that may be utilized within the fast-sampling time interval <NUM> may vary depending on the configuration and hardware-based capabilities (e.g., Field Programmable Gate Array (FPGA) capabilities, etc.) to switch among different link bit rates and achieve clocking locks for each rate in order to attempt decoding at each rate. In at least one embodiment, the number of iterations of fast-sampling time periods <NUM> may be set to at least one iteration such that all link bit rates of a configured a link bit rate fast-sampling set <NUM> are utilized for at least one full fast-sampling time period <NUM> within a fast-sampling time interval <NUM>. Although a complete single iteration of fast-sampling time period <NUM> is sufficient for determining a common matching link bit rate, it may be preferable in some embodiments, depending on configuration and hardware-based capabilities, to set the number of intervals to some other small number (e.g., <NUM>, <NUM>, etc.) such that multiple iterations may be utilized within a fast-sampling time interval <NUM>.

In at least one embodiment, the following fast-sampling procedure may be used by Proxy Slave <NUM> to achieve a HFN sync for a CPRI bit stream transmitted by REC <NUM>.

Consider example details illustrated in <FIG> in which REC <NUM> starts transmitting a CPRI bit stream at a time <NUM>(<NUM>). At a time <NUM>(<NUM>), Proxy Slave <NUM> starts attempting to receive and decode the CPRI bit stream for an N number of fast-sampling time periods <NUM> within fast-sampling time intervals <NUM> such that a common matching link bit rate with REC <NUM> is achieved at <NUM>(<NUM>).

Thus, for fronthaul network <NUM>, embodiments herein provide that Proxy Slave <NUM> will try to receive the CPRI stream using all its configured rates one or multiple times within the fast-sampling time interval <NUM> of <NUM>-<NUM> seconds so that if there is a common matching link bit rate transmitted by REC <NUM> and available with Proxy Slave <NUM>, the common matching link bit rate is found with a fast-sampling time interval <NUM> of <NUM>-<NUM> seconds. Using fast-sampling by Proxy Slave <NUM>, embodiments herein provide for the ability to achieve deterministic end-to-end CPRI link synchronization between the REC <NUM> and RE <NUM>, as discussed in further detail herein.

<FIG> is a simplified flowchart illustrating example operations <NUM> to perform CPRI bit stream fast-sampling by a proxy node, according to an example embodiment. In at least one embodiment, operations <NUM> may be performed by a proxy node, such as Proxy Slave <NUM> for fronthaul network <NUM> of <FIG>. Reference is also made to <FIG> and <FIG> in connection with the description of <FIG>.

In at least one embodiment, operations <NUM> may begin at <NUM> and may include receiving, by the proxy node (e.g., Proxy Slave <NUM>), a CPRI bit stream transmitted by a radio equipment controller (e.g., REC <NUM>) in which the CPRI bit stream is transmitted within a transmit time interval of the radio equipment controller.

At <NUM>, the operations may include fast-sampling, by the proxy node, the CPRI bit stream to attempt to decode the CPRI bit stream using one of a plurality of link bit rates configured for the proxy node and achieve a hyper frame number synchronization with the radio equipment controller. At <NUM>, the operations include determining whether the hyper frame number synchronization is achieved for a common matching link bit rate. The hyper frame number synchronization can be achieved on successful decode of the received CPRI bit stream at a common matching link bit rate.

Based on a determination at <NUM> that the hyper frame number synchronization is not achieved, the operations include selecting, at <NUM>, a different link bit rate of the plurality of configured link bit rates (e.g., the next highest link bit rate are re-starting from the lowest link bit rate) and continuing the fast-sampling at <NUM>. For example, the proxy node may attempt to decode the CPRI bit stream and achieve the hyper frame number synchronization for each of a plurality of link bit rates configured for a fast-sampling time period by performing fast-sampling during at least one fast-sampling time interval configured for the proxy node (e.g., link bit rates configured for link bit rate fast-sampling set <NUM> based on the Proxy Slave <NUM> capability set, which are used to attempt HFN sync with REC during fast-sampling time period <NUM> of fast-sampling time interval <NUM>).

Based on a determination at <NUM> that the hyper frame number synchronization is achieved, the operations continue to <NUM> at which the fast-sampling by the proxy node is stopped. At <NUM>, the operations may include the proxy node performing one or more other operations.

Referring to <FIG> is a simplified diagram illustrating example details associated with operations <NUM> to provide link establishment between the REC <NUM> and RE <NUM> of the fronthaul network <NUM> of <FIG>, according to an example embodiment.

In at least one embodiment, operations <NUM> to provide L1 link auto-negotiation and link establishment between the REC <NUM> and RE <NUM> may be generally performed as follows:.

Operations <NUM> do not guarantee a highest or optimal link bit rate for the CPRI link between REC <NUM> and RE <NUM>. However, these operations will help in achieving the highest or optimal link rate eventually. As per CPRI Specification v7. <NUM>, once the CPRI link is established, the REC and RE may negotiate using the C&M protocol and decide to re-establish the link using a better rate. Thus, in some embodiments, REC <NUM> can issue a RESET on the link and re-start the link synchronization using a 'target' best rate. The Proxy Slave <NUM> will notice LOS on the link during this time and will re-initiate its start-up state machine using fast-sampling for the link synchronization. Thereafter, using the operations <NUM> will result in link synchronization at the new link rate.

Additional details related to operations <NUM> are provided herein, below. Before discussing the additional details associated with operations <NUM>, various pre-requisites for L1 link auto-negotiation may be considered. In various embodiments, pre-requisites for starting operations <NUM> associated with L1 link auto-negotiation between REC <NUM> and RE <NUM> may include, but not be limited to: that Proxy Slave <NUM> and Proxy Master <NUM> are configured or otherwise synchronized using a control protocol to have common subset of link bit rates (e.g., they do not necessarily have to have the same set of link bit rates); the same RoE mapperType value is set to be the same at both Proxy Slave <NUM> and Proxy Master <NUM> (i.e., both support the same mapperType mode of either the Tunneling mode or the Line coding aware mode, as specified in the IEEE <NUM> standards); that packet-based communication between Proxy Slave <NUM> and Proxy Master <NUM> via Ethernet network <NUM> is operational; and that REC <NUM> and RE <NUM> of varied link bit rate capabilities are set up and ready for L1 link negotiation in fronthaul network <NUM>. Other pre-requisites for starting operations <NUM> may be considered, as discussed herein.

In at least one embodiment, operations <NUM> may begin at <NUM> at which Proxy Slave <NUM> will try to establish HFN sync with REC <NUM>. Proxy Slave <NUM> will follow the standard procedure described in CPRI v7. <NUM> Specification for the operations at <NUM> in which REC <NUM> will transmit a CPRI bit stream and change its transmit link bit rate every T1 time interval (i.e., <NUM>-<NUM> seconds). Proxy Slave <NUM> performs fast-sampling on the stream and may find a common matching link bit rate within its fast-sampling time interval (i.e., <NUM>-<NUM> seconds) for the REC transmit time interval T1; otherwise, it may take multiple fast-sampling time intervals (e.g., depending on the number of rates configured for the capability set of the REC <NUM>, for example, <NUM>*T1 time interval in the worst case for four rates configured) to complete the rate matching with a match found or lack of a common match. For the operations of <FIG>, it is assumed that Proxy Slave <NUM> determines common matching link bit rate with REC <NUM>.

Further differing from standard link negotiation operations described in CPRI v7. <NUM> Specification, on reaching HFN sync at <NUM>, Proxy Slave <NUM> will not transmit back towards REC <NUM> at the link bit rate. Rather, the operations may include, at <NUM>, Proxy Slave <NUM> packetizing/encapsulating the CPRI bit stream received from REC <NUM> into RoE frames (e.g., into the RoE payload of RoE frames) and transmitting the RoE frames encapsulated within Ethernet frames (towards the RE <NUM> direction) to Proxy Master <NUM> via Ethernet network <NUM>. In the RoE header of the RoE frames, Proxy Slave <NUM> will indicate the current CPRI link bit rate with which it has achieved the HFN sync with REC <NUM>. For example, in at least one embodiment, <NUM>-bits from the optional reserved bits field in the orderInfo - seqNum field in the RoE header can be used for carrying the CPRI link bit rate information from Proxy Slave <NUM> to Proxy Master <NUM> during L1 link auto-negotiation operations. Additional details related to use of the RoE header to communicate link bit rate information are discussed below with reference to <FIG>.

Referring again to <FIG>, the operations may further include, at <NUM>, Proxy Master <NUM>, on receiving the RoE frames from Proxy Slave <NUM>, determining the CPRI link bit rate information from the RoE header and begin playing out (e.g., transmitting) the CPRI bit stream towards the RE <NUM> as per the same CPRI link bit rate determined from the RoE header of the RoE frames. For example, Proxy Master <NUM> can use the received RoE frames and extract out/de-map the radio data from the received RoE frames to transmit the CPRI bit stream to RE <NUM> at <NUM>.

It should be noted that Proxy Master <NUM> will receive the RoE frames after a propagation delay from REC <NUM> to Proxy Master <NUM>. However, the propagation delay will be very small (less than a millisecond) as compared to the overall time window of T1 time (<NUM>-<NUM> seconds) that occurs before REC <NUM> will move to a new link bit rate.

As Proxy Master <NUM> is transmitting the CPRI bit stream at <NUM>, the operations may include, simultaneously at the other end of the CPRI interconnection with Proxy Master <NUM>, the CPRI port of RE <NUM> is attempting, at <NUM>, to receive and decode the CPRI bit stream directly at the highest available link bit rate for the capability set configured for RE <NUM>.

As per the standard CPRI v7. <NUM> Specification procedure, RE <NUM> will be selecting, at <NUM>, different line bit rates after every T2 time interval (<NUM>-<NUM> seconds) and will be repeating the same procedure of attempting to receive the CPRI bit stream until RE <NUM> achieves the HFN sync (i.e., four consecutive successful detections of the SYNC byte in the received CPRI bit stream). Thus, the operations at <NUM>, <NUM>, <NUM>, and <NUM> will be repeated again and again for different link bit rates at REC <NUM> and RE <NUM> as per the REC T1 time intervals (<NUM>-<NUM> seconds) and REC <NUM> T2 time intervals (<NUM>-<NUM> seconds) in which REC <NUM> continues selecting a new link bit rate for transmission and reception after every T1 time interval (<NUM>-<NUM> seconds) until RE <NUM> achieves the HFN sync for the CPRI bit stream transmitted by Proxy Master <NUM>.

Upon RE <NUM> reaching HFN sync, the operations may include, at <NUM>(<NUM>), RE <NUM> starting to transmit a CPRI bit stream to Proxy Master <NUM> using the same link bit rate at which the HFN sync was achieved by RE <NUM>. Proxy Master <NUM>, on receiving the CPRI bit stream transmitted by RE <NUM>, determines, at <NUM>(<NUM>), that the end-to-end L1 synchronization has been reached between REC <NUM> and RE <NUM> and updates the internal state of the CPRI port state machine as per CPRI Specification v7. The operations at <NUM>(<NUM>) may further include Proxy Master <NUM> starting to map the CPRI bit stream received from RE <NUM> into RoE frames (e.g., into the RoE payload of the frames) and transmitting the RoE frames encapsulated within Ethernet frames to Proxy Slave <NUM> via Ethernet network <NUM>.

Recall, Proxy Slave <NUM>, via operations at <NUM>/<NUM>, has been continuing to fast-sample, sync, and frame the REC <NUM> transmitted CPRI bit stream for a CPRI link bit rate (as varied by REC <NUM> through the T1 time intervals) in RoE frames with the link bit rate information included in the RoE header of the frames and transmitting the RoE frames (encapsulated within Ethernet frames) towards Proxy Master <NUM>/RE <NUM>. At <NUM>(<NUM>), the operations include Proxy Slave <NUM> receiving the RoE frames from Proxy Master <NUM> and, on receiving the RoE frames, Proxy Slave <NUM> beginning to de-map the received RoE frames and start playing out (e.g., transmitting) the CPRI bit stream from the RoE frames towards REC <NUM>. Proxy Slave <NUM> also updates the internal state of the CPRI port state machine per CPRI Specification v7. <NUM> indicating L1 sync is achieved from the RE <NUM> side.

When REC <NUM> is be able to receive and decode the Proxy Slave <NUM> transmitted CPRI bit stream, which was originally initiated by RE <NUM>, the L1 link auto-negotiations will be considered complete as both REC <NUM> and RE <NUM> are able to communicate with each other via an established CPRI link. The operations may further include REC <NUM> and RE <NUM> performing CPRI higher layer (e.g., L2 frame alignment/sync, vendor specific negotiations, etc.) synchronization following completion of the L1 link negotiations culminating in the established CPRI link.

As illustrated in <FIG>, Proxy Slave <NUM> and Proxy Master <NUM> may facilitate L1 link auto-negotiation between REC <NUM> and RE <NUM> to facilitate deterministic link synchronization and CPRI link establishment between REC <NUM> and RE <NUM> for fronthaul network <NUM>. An optimal link rate, if not achieved through operations <NUM>, can also be achieved depending on C&M negotiations.

Features associated with operations <NUM> for facilitating the L1 link auto-negotiation operations between REC <NUM> and RE <NUM> may include, as discussed at <NUM>, performing fast-sampling by Proxy Slave <NUM> for the REC <NUM> transmitted CPRI bit stream and, after reaching HFN sync with REC <NUM>, Proxy Slave <NUM> does not transmit a CPRI bit stream back to REC <NUM> at the link bit rate, rather Proxy Slave <NUM> starts packetizing the CPRI bit stream received from REC <NUM> in RoE frames and transmits the RoE frames towards RE <NUM> by way of Proxy Master <NUM>. Such operations are a change in the general CPRI port state machine configured for Proxy Slave <NUM> in that Proxy Slave <NUM> should not transmit back towards the REC <NUM> at <NUM> as that would enable achieving HFN sync with REC <NUM>. Rather Proxy Slave <NUM> waits until RoE frames are received from Proxy Master <NUM> before it transmits a CPRI bit stream towards REC <NUM> (e.g., <NUM>(<NUM>) and <NUM>(<NUM>)).

Thus, Proxy Slave <NUM> and Proxy Master <NUM> play specific roles to enable the L1 link auto-negotiation operations; thereby providing for the ability for HFN sync by REC <NUM> to be achieved for the CPRI bit stream as is transmitted by RE <NUM>.

By providing changes in operations of the CPRI port state machine at Proxy Slave <NUM> rather than REC <NUM>, features associated with L1 link auto-negotiation as described herein may be achieved without affecting proprietary vendor developed REC and RE units.

As discussed at <NUM>, Proxy Slave <NUM> also indicates the current CPRI link bit rate in the RoE header of RoE frames transmitted toward Proxy Master <NUM>, which indicates the link bit rate that Proxy Master <NUM> is to use for the CPRI bit stream transmitted to RE <NUM> (at <NUM>). By decoding the CPRI link bit rate information from the RoE header, Proxy Master <NUM> can transmit a CPRI bit stream to RE <NUM> as per the determined link bit rate using the radio data contents of the received RoE frame; thereby providing for the ability for RE <NUM> to achieve HFN sync at the link bit rate transmitted by REC <NUM>.

As noted previously, operations <NUM> do not guarantee a highest or optimal link bit rate for the CPRI link between REC <NUM> and RE <NUM>. However, operations <NUM> will help in achieving the highest or optimal link rate eventually. As per CPRI Specification v7. <NUM>, once the CPRI link is established, the REC and RE may negotiate using the C&M protocol and decide to re-establish the link using a better rate. Thus, in some embodiments, REC <NUM> can issue a RESET on the link and re-start the link synchronization using a 'target' best rate. The Proxy Slave <NUM> will notice LOS on the link during this time and will re-initiate its start-up state machine using fast-sampling for the link synchronization. Thereafter, using the operations <NUM> will result in link synchronization at the new link rate.

Referring to <FIG> are simplified diagrams illustrating example details associated with an Ethernet frame <NUM> including a RoE frame <NUM> that may be used to communicate link bit rate information, according to an example embodiment. Reference is also made to preceding FIGs. in connection with the description of <FIG>.

<FIG> includes Ethernet frame <NUM> within which RoE frame <NUM> is encapsulated, according to an example embodiment. Ethernet frame <NUM> include various fields including, but not limited to, a Destination Address (DA) field <NUM>, a Source Address (SA) field <NUM>, an Ethernet Type (EtherType) field <NUM>, and a Frame Check Sequence (FCS) field <NUM>. Ethernet frame <NUM> includes RoE frame <NUM> encapsulated therein. RoE frame <NUM> includes a RoE header <NUM> and a RoE payload <NUM>.

In at least one embodiment of Ethernet frame <NUM>, DA field <NUM> may be set to the destination Media Access Control (MAC) address for the destination node (e.g., Proxy Master <NUM> or Proxy Slave <NUM>), depending on whichever node to which the RoE frame is to be transmitted; the SA field <NUM> may be set to the source MAC address for the source node (e.g., Proxy Master <NUM> or Proxy Slave <NUM>), depending on whichever node from which the RoE frame is transmitted; the EtherType field <NUM> may be set to type '0xFC3D', indicating an RoE EtherType; and the FCS field <NUM> may be set according to a cyclic redundancy check value, which can be set/computed based on various fields, data, etc. of the Ethernet frame <NUM>.

In at least one embodiment, RoE header <NUM> includes various fields including a Packet Sub Type (subType) field <NUM>, a Flow Identifier (flowID) field <NUM>, a Length field <NUM>, and an Ordering Information (orderInfo) field <NUM>.

<FIG> illustrates other example details associated with RoE frame <NUM> including RoE header <NUM> and RoE payload <NUM>, according to an example embodiment. In at least one embodiment, subType field <NUM> may be set to indicate a RoE structure-agnostic data sub type indicating that RoE payload <NUM> includes a radio data payload packet, flowID field <NUM> may be set to a value indicating a flow/connection between Proxy Slave <NUM> and Proxy Master <NUM>, and Length field <NUM> may be set to a value based on the RoE payload <NUM> size. The RoE payload <NUM> includes packetized radio data (e.g., CPRI bit stream) mapped therein.

According to the IEEE <NUM> standards, the orderInfo field <NUM> is a <NUM>-bit field that can contain sequence number information or timestamp information carried with each RoE frame <NUM>. In general, the sequence number information can be used to identify the order of successive packets. For sequence number information contained in RoE header <NUM>, orderInfo field <NUM> contains a <NUM>-bit Sequence Number (seqNum) field 626a, as illustrated in <FIG>. Thus, orderInfo field <NUM> can be configured as seqNum field 626a, in at least one embodiment.

As illustrated in <FIG>, seqNum field 626a (of orderInfo field <NUM>) includes a p-counter field <NUM> having a number of p-bits that can be used to indicate a p-counter value, a q-counter field <NUM> having number of q-bits that can be used to indicate a q-counter value, and an optional reserved bits field <NUM> having <NUM>-bits that can be used, in at least one embodiment, to carry CPRI link bit rate information.

For structure-agnostic CPRI mapping, the RoE frame header field is the ideal place to carry CPRI link bit rate information. The information about the link bit rate is to be carried in data plane because usage of any out-of-band control plane channel will cause un-deterministic delays for this byte and frame alignment centric time sensitive link negotiation procedure.

The contents of the p-counter field <NUM> and the q-counter field <NUM> are specified by the IEEE <NUM> Specification. However, the contents of the optional reserved bits field <NUM> are not specified by the IEEE <NUM> Specification. Additionally, as per the IEEE <NUM> Specification, the number of p-bits that can be used for the p-counter field <NUM> and the number of q-bits that can be used for the q-counter field <NUM>, which indicate the size of p and q-counter fields <NUM>, <NUM>, respectively, is flexible (e.g., the values/sizes can be varied). Any values that can clearly indicate the start of a radio frame boundary and the sequencing of the frames can be used in a RoE mapper/de-mapper implementation.

Accordingly, in at least one embodiment, the <NUM>-bits of the optional reserved bits field <NUM> of the sequNum field 626a (of the orderInfo field <NUM>) in the RoE header <NUM> can be used to carry CPRI link bit rate information within RoE frames transmitted from Proxy Slave <NUM> to Proxy Master <NUM> during L1 link auto-negotiation operations.

In at least one embodiment, CPRI link bit rate information carried in the optional reserved bits field <NUM> may be a value indicating a CPRI link bit rate option. Per CPRI Specification v7. <NUM>, currently supported CPRI link bit rate options (in Megabits per second (Mbit/s) include eleven (<NUM>) link bit rate options, as follows:.

In at least one embodiment, the binary value of '0000b' for the <NUM>-bits of the optional reserved bits field <NUM> may be reserved and the values from one (<NUM>) (e.g., binary '0001b') onwards may be used for mapping to a CPRI link bit rate option. Considering <NUM> rates currently supported by CPRI Specification v7. <NUM>, use of the <NUM>-bits of the optional reserved bits field <NUM> may be sufficient and also allow for support of <NUM> additional rates in the future. Thus, the value indicating the CPRI link bit rate option may be included within <NUM> to <NUM>-bits of the optional reserved bits field <NUM> (e.g., depending on the value to be included).

Use of the <NUM>-bits of the of the optional reserved bits field <NUM> are only to be used during link negotiation operations and are not to be used for this purpose when the CPRI link is up (e.g., established) between REC <NUM> and RE <NUM>.

In at least one embodiment, each of the Proxy Slave <NUM> and the Proxy Master <NUM> can be configured with a CPRI link bit rate options table that identifies each of a given value (e. g, values <NUM>-<NUM>) that is associated with each of a given CPRI link bit rate option for each of a given CPRI link bit rate that may be used within fronthaul network <NUM>. For example, during L1 link auto-negotiation operations, Proxy Slave <NUM> can use its CPRI link bit rate options table to determine a value for a given link bit rate in use (e.g., the rate of the CPRI bit stream transmitted by REC <NUM> for which a HFN sync is achieved by Proxy Slave <NUM> using fast-sampling) in order for Proxy Slave <NUM> to include the value in the optional reserved bits field of a seqNum field for an orderInfo field of an RoE header of an RoE frame for each Ethernet frame that is transmitted to Proxy Master <NUM>. Proxy Master <NUM>, upon receiving an Ethernet frame during L1 link auto-negotiation operations can determine (e.g., decode or identify) the link bit rate in use (by the REC <NUM>) by performing a look-up on its CPRI bit rate options table using the value included in an RoE header of the RoE frame within the Ethernet frame in order to transmit (after de-mapping from the RoE payload) the CPRI bit stream to RE <NUM> at the identified link bit rate.

This use of <NUM> optional reserved bits does not violate the IEEE <NUM> standard and also leaves enough bits for use as p/q-bits, which should be sufficient for the desired objective of orderInfo field <NUM> (e.g., for carrying sequence number information via the p/q-bits of the p-counter field <NUM> and the q-counter field <NUM>).

Thus, use of reserved bits in the seqNum field 626a from orderInfo field <NUM> in the RoE header <NUM> provides for the ability for Proxy Slave <NUM> to indicate the link bit rate in use to Proxy Master <NUM> during L1 link auto-negotiation operations such as operations as discussed above at <NUM> and <NUM> of <FIG>.

Referring to <FIG> is a simplified flowchart illustrating example operations <NUM> to provide link establishment between a radio equipment controller and a radio equipment in a fronthaul network, according to an example embodiment. In at least one embodiment, operations <NUM> can be performed via a Proxy Master, a Proxy Slave, a radio equipment controller (REC), a radio equipment (RE), and an Ethernet network for a fronthaul network, such as Proxy Master <NUM>, Proxy Slave <NUM>, REC <NUM>, RE <NUM>, and Ethernet network <NUM> for fronthaul network <NUM> as discussed herein.

In at least one embodiment prior to the start of operations <NUM>, it is assumed that: the Proxy Slave and the Proxy Master are configured or otherwise synchronized using a control protocol to have common subset of link bit rates (e.g., they do not necessarily have to have the same set of link bit rates); the same RoE mapperType value is set to be the same at both the Proxy Slave and the Proxy Master (i.e., both support the same mapperType mode of either the Tunneling mode or the Line coding aware mode, as specified in the IEEE <NUM> standards); packet-based communication between the Proxy Slave and the Proxy Master via the Ethernet network is operational; the radio equipment controller and the Radio Equipment of varied link bit rate capabilities are set up and ready for Layer <NUM> link negotiations in the fronthaul network; and a CPRI link bit rate options table is configured for each of the Proxy Slave and the Proxy Master in which each table is configured to identify each of a given value that is to be associated with each of a given CPRI link bit rate option for each of a given CPRI link bit rate that may be used within the fronthaul network.

In at least one embodiment, operations <NUM> may begin at <NUM> and may include performing, for one or more link bit rates of a plurality of link bit rates configured for the fronthaul network, CPRI Layer <NUM> link auto-negotiation operations (<NUM>) to establish a CPRI link between the radio equipment controller and the radio equipment of the fronthaul network.

In at least one embodiment, the CPRI Layer <NUM> link auto-negotiation operations <NUM> may include at <NUM>, fast-sampling, by the Proxy Slave, a first CPRI bit stream transmitted by the radio equipment controller to achieve a hyper frame number synchronization with the radio equipment controller at a link bit rate. The fast-sampling by the Proxy Slave can be performed for one or more fast-sampling intervals, as discussed herein.

The operations at <NUM> are an iterative process that continue to be performed between the Proxy Slave and the radio equipment controller during the transmit time interval of the radio equipment controller until a hyper frame number synchronization is achieved for a second CPRI bit stream transmitted from the Proxy Slave to the radio equipment controller, as discussed further below. The Proxy Slave does not transmit back to the radio equipment controller when the hyper frame number synchronization is achieved at <NUM>; rather the operations can include the Proxy Slave waiting until RoE frames are received from the Proxy Master before transmitting back to the radio equipment controller (e.g., transmitting the second CPRI bit stream contained in the RoE frames received from the Proxy Master, discussed below) at the link bit rate for which the hyper frame number synchronization is achieved for the first CPRI bit stream received from the radio equipment controller.

At <NUM>, the operations may include, upon the proxy slave achieving the hyper frame number synchronization with the radio equipment controller for the first bit stream at the link bit rate, communicating the first CPRI bit stream and the link bit rate from the Proxy Slave to the Proxy Master. In at least one embodiment, the operations at <NUM> can include the Proxy Slave mapping the first CPRI bit stream into the RoE payload of RoE frames using structure-agnostic RoE mapping operations and including link bit rate information associated with the link bit rate within each RoE header of each RoE frame during the L1 link auto-negotiation operations <NUM>. In at least one embodiment, the link bit rate information can be included as a value indicating a link bit rate option in which the value can be included within <NUM> to <NUM>-bits (e.g., depending on the value to be included) of an optional reserved bits field of a seqNum field for a orderInfo field of an RoE header. The operations at <NUM> can further include encapsulating each RoE frame within an Ethernet frame and communicating each Ethernet frame to the Proxy Master from the Proxy Slave via the Ethernet network.

At <NUM>, the operations may include transmitting, by the proxy master, the first CPRI bit stream to the radio equipment at the link bit rate. The operations at <NUM> may be performed provided that the proxy master has the link bit rate configured in its link bit rate table. If the link bit rate received is not something that it supports, it will not transmit the CPRI bit stream towards the radio equipment. In at least one embodiment, the operations at <NUM> can include the Proxy Master receiving each RoE frame and determining the link bit rate via the RoE header for the RoE frame (e.g., by performing a look-up using the value included in the optional reserved bits field of the seqNum field for the orderInfo field), determining that it supports the link bit rate, and de-mapping the CPRI bit stream from the RoE payload for the RoE frame (e.g., using structure-agnostic RoE de-mapping operations) in order to transmit the first CPRI bit stream to the radio equipment at the link bit rate identified in the RoE header. At <NUM>, the operations may include, the radio equipment, upon achieving a hyper frame number synchronization for the received first CPRI bit stream at the link bit rate, transmitting a second CPRI bit stream to the Proxy Master.

At <NUM>, the operations may include, upon the Proxy Master achieving a hyper frame number synchronization with the radio equipment for the second CPRI bit stream transmitted by the radio equipment at the link bit rate, communicating the second CPRI bit stream from the Proxy Master to the Proxy Slave. In at least one embodiment, the operations at <NUM> can include the Proxy Master mapping the second CPRI bit stream received from the radio equipment into the RoE payload of RoE frames using structure-agnostic RoE mapping operations, encapsulating each RoE frame into an Ethernet frame, and communicating each Ethernet frame to the Proxy Slave via the Ethernet network.

At <NUM>, the operations may include, transmitting, by the Proxy Slave, the second CPRI bit stream to the radio equipment controller. In at least one embodiment, the operations at <NUM> may include the Proxy Slave de-mapping the second CPRI bit stream from the RoE payload for each RoE frame (e.g., using structure-agnostic RoE de-mapping operations) received from the Proxy Master and transmitting the second CPRI bit stream to the radio equipment controller at the link bit rate at which the Proxy Slave has achieved a hyper frame number synchronization for the CPRI first bit stream transmitted from the radio equipment controller to the Proxy Slave.

At <NUM>, the operations may include determining, by the radio equipment controller, whether a hyper frame number synchronization is achieved by the radio equipment controller for the second CPRI bit stream received from the Proxy Slave at the link bit rate. In at least one embodiment, the operations at <NUM> can include the radio equipment controller attempting to perform four consecutive detections of the SYNC byte within the received second CPRI bit stream. If the radio equipment controller is unable to perform the four consecutive detections within the T1 transmit time interval (e.g., <NUM>-<NUM> seconds), it is determined at <NUM> that the hyper frame number synchronization is not achieved and the radio equipment controller begins to transmit the first CPRI bit stream at the next link bit rate from its configured capability set (e.g., the next highest rate, if available, in the round robin manner, as discussed above), and the operations continue to be performed at <NUM> at which the Proxy Slave continues Layer <NUM> link negotiations with the radio equipment controller to achieve a hyper frame number synchronization with the radio equipment controller at the next link bit rate for the first CPRI bit stream transmitted by the radio equipment controller and the operations continue therefrom as discussed above.

If, at <NUM>, the radio equipment controller determines that the hyper frame number synchronization is achieved, the operations can continue to <NUM>, at which the Layer <NUM> link auto-negotiations are completed and the CPRI link is established between the radio equipment controller and the radio equipment that allows bi-directional traffic (e.g., radio data) to be communicated between the radio equipment controller and the radio equipment when the radio equipment controller achieves a hyper frame number synchronization for the second CPRI bit stream transmitted by the proxy slave at a particular link bit rate.

At <NUM>, the operations may include the Proxy Slave and the Proxy Master performing normal operations (e.g., performing higher layer CPRI and/or vendor specific negotiation operations, transmitting/receiving CPRI bit streams, performing mapping/de-mapping operations, transmitting/receiving Ethernet frames, monitoring for Layer <NUM> link alarms, etc.) to facilitate radio data communications between the radio equipment controller and the radio equipment. In at least one embodiment, operations at <NUM> include, the Proxy Slave not communicating the link bit rate to the Proxy Master during normal operations.

Referring to <FIG> is a simplified flow chart illustrating example operations to communicate link bit rate information using a RoE header of a RoE frame, according to an example embodiment. In at least one embodiment, operations <NUM> can be performed via a first proxy node (e.g., a Proxy Slave), a second proxy node (e.g., a Proxy Master), and an Ethernet network for a fronthaul network, such as Proxy Slave <NUM>, Proxy Master <NUM>, and Ethernet network <NUM> for fronthaul network <NUM> as illustrated herein.

For operations <NUM>, it is assumed that link auto-negotiation operations are being performed to establish a CPRI link between a radio equipment controller and a radio equipment in the fronthaul network and that a CPRI link bit rate options table is configured for each of the first proxy node and the proxy node in which each table is configured to identify each of a given value that is to be associated with each of a given CPRI link bit rate option for each of a given CPRI link bit rate that may be used or supported within the fronthaul network.

In at least one embodiment, operations <NUM> may begin at <NUM> and may include determining CPRI link bit rate information to communicate from the first proxy node to the second proxy node. In at least one embodiment, the CPRI link bit rate information may be a value that is associated with to a particular CPRI link bit rate option that is associated with a particular CPRI link bit rate within the CPRI link bit rate options table configured for the first proxy node. For example, the first proxy node can determine CPRI link bit rate information to communicate to the second proxy node based on a CPRI link bit rate at which the first proxy node has achieved a hyper frame number sync for a CPRI bit stream received by the first proxy node (e.g., a CPRI bit stream transmitted from the radio equipment controller to the first proxy node, which is fast-sampled by the first proxy node to achieve the hyper frame number sync) and the first proxy node performing a look-up using the CPRI link bit rate options table to determine a corresponding value (e.g., option number) that is associated with the CPRI link bit rate.

The operations may include, at <NUM>, the first proxy node providing the CPRI link bit rate information within a RoE header of a RoE frame. In at least one embodiment, the link bit rate information may be provided within the optional reserved bits field of a seqNum field for an orderInfo field within the RoE frame. For example, the first proxy node can include the value determined from the CPRI link bit rate options table look-up within the optional reserved bits field of a seqNum field for an orderInfo field within the RoE frame.

At <NUM>, the operations may include the first proxy node mapping a CPRI bit stream into the RoE payload of the RoE frame. In at least one embodiment, the first proxy node can map the CPRI bit stream into the RoE payload using structure-agnostic RoE mapping operations, as prescribed by the IEEE <NUM> standards. At <NUM>, the operations may include the first proxy node encapsulating the RoE frame into an Ethernet frame. At <NUM>, the operations may include the first proxy node transmitting the Ethernet frame to the second proxy node.

At <NUM>, the operations may include the second proxy node determining the CPRI link bit rate information from the RoE header. In at least one embodiment, the operations at <NUM> can include the second proxy node de-encapsulating the RoE frame from the Ethernet frame and performing a look-up on its CPRI link bit rate options table based on the value included in the optional reserved bits field of the seqNum field for the orderInfo field within the RoE frame to determine the CPRI link bit rate. In at least one embodiment, the determined CPRI link bit rate can be used by the second proxy node to transmit the CPRI bit stream included in the RoE payload (once de-mapped from the RoE payload) to a radio equipment in order to facilitate other link auto-negotiation operations, as discussed herein.

Referring to <FIG> is a simplified block diagram illustrating example details associated with a proxy node such as a Proxy Master <NUM> for implementing operations described herein, according to an example embodiment. Proxy Master <NUM> may provide operations associated with a Proxy Master within a fronthaul network as discussed herein such as, for example, Proxy Master <NUM> of fronthaul network <NUM>.

The embodiment of <FIG> illustrates Proxy Master <NUM>, which includes one or more processor(s) <NUM>, one or more memory element(s) <NUM>, a bus <NUM>, one or more network interface element(s) <NUM>, and storage <NUM>. Memory element(s) <NUM> may include instructions for proxy master logic <NUM> and master link auto-negotiation logic <NUM>. Memory element(s) <NUM> may also include a CPRI link bit rate options table <NUM>.

In at least one embodiment, processor(s) <NUM> is/are at least one hardware processor configured to execute various tasks, operations, and/or functions for Proxy Master <NUM> according to software and/or instructions configured for Proxy Master <NUM>. In at least one embodiment, memory element(s) <NUM> is/are configured to store data, information, software and/or instructions associated with Proxy Master <NUM> and logic configured for memory element(s) <NUM>. In at least one embodiment, bus <NUM> can be configured as an interface that enables one or more elements of Proxy Master <NUM> (e.g., network interface element(s) <NUM>, processor(s) <NUM>, memory element(s) <NUM> (and logic, etc. configured therein), etc.) to communicate in order to exchange information and/or data, to perform operations, etc. In at least one embodiment, a fast kernel-hosted interconnect may be employed for Proxy Master <NUM>, potentially using shared memory between processes (e.g., logic, etc.), which can enable efficient communication paths between the processes.

In various embodiments, network interface element(s) <NUM> enables communications (wired or wireless) between Proxy Master <NUM> and other network elements or nodes, via one or more input/output (I/O) elements <NUM> (e.g., any number/combination of CPRI ports, Ethernet ports, transceivers, etc.) at which data, information, etc. is received and transmitted to facilitate operations discussed for various embodiments described herein. In various embodiments, network interface element(s) <NUM> (e.g., hardware, software, firmware, logic, etc.) can be configured to include any combination of Ethernet interface elements, CPRI interface elements, Radio Frequency (RF) interface elements (e.g., for WiFi or any other unlicensed spectrum communications, for 3GPP or any other licensed spectrum communications, and/or or any other similar network interface elements to enable communications (e.g., CPRI bit stream/RoE frame mapping/de-mapping, Ethernet frame encapsulation/de-encapsulation, etc.) for Proxy Master <NUM> within a fronthaul network (e.g., fronthaul network <NUM>). Proxy Master <NUM> can include any suitable interfaces for receiving, transmitting, and/or otherwise communicating data and/or information in a network environment.

In various embodiments, storage <NUM> can be configured to store data, information and/or instructions associated with Proxy Master <NUM> and/or logic configured for memory element(s) <NUM>. Note that in certain examples, storage <NUM> can be consolidated with memory elements <NUM> (or vice versa), and/or the storage/memory elements can overlap/exist in any other suitable manner.

In at least one embodiment, CPRI link bit rate options table <NUM> may include a table in which each of a given value that is to be associated with each of a given CPRI link bit rate option for each of a CPRI link bit rate that may be used or supported within a fronthaul network (e.g., each of values <NUM>-<NUM> associated with each of <NUM>-<NUM> CPRI link bit rate options for each of <NUM>-<NUM> supported CPRI link bit rates as prescribed by CPRI Specification v7.

In various embodiments, proxy master logic <NUM> can include instructions that, when executed (e.g., by processor(s) <NUM>) cause Proxy Master <NUM> to perform operations, which can include, but not be limited to: performing control, management, etc. operations associated with Proxy Master <NUM> (e.g., for CPRI bit steam/RoE frame mapping/de-mapping operations, Ethernet frame encapsulations/de-encapsulations, monitoring operations, and/or any other normal operations); cooperating and/or interacting with other logic (internal and/or external to Proxy Master <NUM>) and/or network interface element(s) <NUM> (e.g., for CPRI bit stream/RoE frame mapping/de-mapping operations, Ethernet frame encapsulations/de-encapsulations, monitoring operations, and/or any other normal operations); maintaining and/or interacting with stored data, information, and/or parameters (e.g., link bit rates); combinations thereof; and/or the like to facilitate operations as discussed for various embodiments described herein.

In various embodiments, master link auto-negotiation logic <NUM> may include instructions that, when executed (e.g., by processor(s) <NUM>) may facilitate various link auto-negotiation operations described herein including, but not limited to: operations associated with link auto-negotiations performed by a Proxy Master described herein; determining a link bit rate based on link bit rate information included in an RoE header; cooperating and/or interacting with other logic (internal and/or external to Proxy Master <NUM>) and/or network interface element(s) <NUM>; maintaining and/or interacting with stored data, information, and/or parameters; combinations thereof; and/or the like to facilitate operations as discussed for various embodiments described herein.

In various embodiments, memory element(s) <NUM> may include any suitable memory element such as random access memory (RAM), dynamic RAM (DRAM), static RAM (SRAM), and/or cache memory. In general, memory element(s) <NUM> can include any suitable volatile or non-volatile computer readable storage media, which may be inclusive of non-transitory tangible media and/or non-transitory computer readable storage media that is capable of storing program/logic/software instructions and/or digital information.

In various embodiments, storage <NUM> may include any suitable storage such as persistent storage, which may be a magnetic disk drive, a solid state hard drive, a semiconductor storage device, read only memory (ROM), an erasable programmable read only memory (EPROM), flash memory, or any other computer readable storage media, which may be inclusive of non-transitory tangible media and/or non-transitory computer readable storage media, that is capable of storing program/logic/software instructions and/or digital information. In some embodiments, the media used by storage <NUM> may also be removable. For example, a removable hard drive may be used for storage <NUM>. Other examples include optical and magnetic disks, thumb drives, and smart cards that are inserted into a drive for transfer onto another computer readable storage medium that is also part of storage <NUM>.

Referring to <FIG> is a simplified block diagram illustrating example details associated with a proxy node such as a Proxy Slave <NUM> for implementing operations described herein, according to an example embodiment. Proxy Slave <NUM> may provide operations associated with a Proxy Slave within a fronthaul network as discussed herein such as, for example, Proxy Slave <NUM> of fronthaul network <NUM>.

The embodiment of <FIG> illustrates Proxy Slave <NUM>, which includes one or more processor(s) <NUM>, one or more memory element(s) <NUM>, a bus <NUM>, one or more network interface element(s) <NUM>, and storage <NUM>. Memory element(s) <NUM> may include instructions for proxy slave logic <NUM> and slave link auto-negotiation logic <NUM>.

In at least one embodiment, processor(s) <NUM> is/are at least one hardware processor configured to execute various tasks, operations, and/or functions for Proxy Slave <NUM> according to software and/or instructions configured for Proxy Slave <NUM>. In at least one embodiment, memory element(s) <NUM> is/are configured to store data, information, software and/or instructions associated with Proxy Slave <NUM> and logic configured for memory element(s) <NUM>. In at least one embodiment, bus <NUM> can be configured as an interface that enables one or more elements of Proxy Slave <NUM> (e.g., network interface element(s) <NUM>, processor(s) <NUM>, memory element(s) <NUM> (and logic etc. configured therein), etc.) to communicate in order to exchange information and/or data, to perform operations, etc. In at least one embodiment, a fast kernel-hosted interconnect may be employed for Proxy Slave <NUM>, potentially using shared memory between processes (e.g., logic, etc.), which can enable efficient communication paths between the processes.

In various embodiments, network interface element(s) <NUM> enables communications (wired or wireless) between Proxy Slave <NUM> and other network elements or nodes, via one or more input/output (I/O) elements <NUM> (e.g., any number/combination of CPRI ports, Ethernet ports, transceivers, etc.) at which data, information, etc. is received and transmitted to facilitate operations discussed for various embodiments described herein. In various embodiments, network interface element(s) <NUM> (e.g., hardware, software, firmware, logic, etc.) can be configured to include any combination of Ethernet interface elements, CPRI interface elements, RF interface elements (e.g., for WiFi or any other unlicensed spectrum communications, for 3GPP or any other licensed spectrum communications, and/or or any other similar network interface elements to enable communications (e.g., CPRI bit stream/RoE frame mapping/de-mapping, etc.) for Proxy Slave <NUM> within a fronthaul network (e.g., fronthaul network <NUM>). Proxy Slave <NUM> can include any suitable interfaces for receiving, transmitting, and/or otherwise communicating data and/or information in a network environment.

In various embodiments, storage <NUM> can be configured to store data, information and/or instructions associated with Proxy Slave <NUM> and/or logic configured for memory element(s) <NUM>. Note that in certain examples, storage <NUM> can be consolidated with memory elements <NUM> (or vice versa), and/or the storage/memory elements can overlap/exist in any other suitable manner.

In various embodiments, proxy slave logic <NUM> can include instructions that, when executed (e.g., by processor(s) <NUM>) cause Proxy Slave <NUM> to perform operations, which can include, but not be limited to: performing control, management, etc. operations associated with Proxy Slave <NUM> (e.g., for CPRI bit steam/RoE frame mapping/de-mapping operations, Ethernet frame encapsulations/de-encapsulations, monitoring operations, and/or any other normal operations); cooperating and/or interacting with other logic (internal and/or external to Proxy Slave <NUM>) and/or network interface element(s) <NUM> (e.g., for CPRI bit stream/RoE frame mapping/de-mapping operations, Ethernet frame encapsulations/de-encapsulations, monitoring operations, and/or any other normal operations); maintaining and/or interacting with stored data, information, and/or parameters (e.g., link bit rates); combinations thereof; and/or the like to facilitate operations as discussed for various embodiments described herein.

In various embodiments, slave link auto-negotiation logic <NUM> may include instructions that, when executed (e.g., by processor(s) <NUM>) may facilitate various link auto-negotiation operations described herein including, but not limited to: operations associated with link auto-negotiations performed by a Proxy Slave described herein (e.g., fast-sampling, etc.); including link bit rate information within RoE headers of RoE frames during link auto-negotiation operations, not including link bit rate information within RoE headers of RoE frames when link auto-negotiation operations are complete; cooperating and/or interacting with other logic (internal and/or external to Proxy Slave <NUM>) and/or network interface element(s) <NUM>; maintaining and/or interacting with stored data, information, and/or parameters; combinations thereof; and/or the like to facilitate operations as discussed for various embodiments described herein.

In various embodiments, memory element(s) <NUM> may include any suitable memory element such as RAM, DRAM, SRAM, and/or cache memory. In general, memory element(s) <NUM> can include any suitable volatile or non-volatile computer readable storage media, which may be inclusive of non-transitory tangible media and/or non-transitory computer readable storage media that is capable of storing program/logic/software instructions and/or digital information.

In various embodiments, storage <NUM> may include any suitable storage such as persistent storage, which may be a magnetic disk drive, a solid state hard drive, a semiconductor storage device, ROM, an EPROM, flash memory, or any other computer readable storage media, which may be inclusive of non-transitory tangible media and/or non-transitory computer readable storage media, that is capable of storing program/logic/software instructions and/or digital information. In some embodiments, the media used by storage <NUM> may also be removable. For example, a removable hard drive may be used for storage <NUM>. Other examples include optical and magnetic disks, thumb drives, and smart cards that are inserted into a drive for transfer onto another computer readable storage medium that is also part of storage <NUM>.

Referring to <FIG> is a simplified block diagram illustrating example details associated with a radio equipment controller <NUM> for implementing operations described herein, according to an example embodiment. In at least one embodiment, radio equipment controller <NUM> may provide operations associated with a radio equipment controller within a fronthaul network as discussed herein such as, for example, REC <NUM> of fronthaul network <NUM>.

The embodiment of <FIG> illustrates radio equipment controller <NUM>, which includes one or more processor(s) <NUM>, one or more memory element(s) <NUM>, a bus <NUM>, one or more network interface element(s) <NUM>, and storage <NUM>. Memory element(s) <NUM> may include instructions for radio equipment controller logic <NUM>.

In at least one embodiment, processor(s) <NUM> is/are at least one hardware processor configured to execute various tasks, operations, and/or functions for radio equipment controller <NUM> according to software and/or instructions configured for radio equipment controller <NUM>. In at least one embodiment, memory element(s) <NUM> is/are configured to store data, information, software and/or instructions associated with radio equipment controller <NUM> and logic configured for memory element(s) <NUM>. In at least one embodiment, bus <NUM> can be configured as an interface that enables one or more elements of radio equipment controller <NUM> (e.g., network interface element(s) <NUM>, processor(s) <NUM>, memory element(s) <NUM> (and logic etc. configured therein), etc.) to communicate in order to exchange information and/or data, to perform operations, etc. In at least one embodiment, a fast kernel-hosted interconnect may be employed for radio equipment controller <NUM>, potentially using shared memory between processes (e.g., logic, etc.), which can enable efficient communication paths between the processes.

In various embodiments, network interface element(s) <NUM> enables communications (wired or wireless) between radio equipment controller <NUM> and other network elements or nodes, via one or more input/output (I/O) elements <NUM> (e.g., any number/combination of CPRI ports, Ethernet ports, transceivers, etc.) at which data, information, etc. is received and transmitted to facilitate operations discussed for various embodiments described herein. In various embodiments, network interface element(s) <NUM> (e.g., hardware, software, firmware, logic, etc.) can be configured to include Ethernet interface elements, CPRI interface elements, RF interface elements (e.g., for WiFi or any other unlicensed spectrum communications, for 3GPP or any other licensed spectrum communications, and/or or any other similar network interface elements to enable communications for radio equipment controller <NUM> within a fronthaul network (e.g., fronthaul network <NUM>). Radio equipment controller <NUM> can include any suitable interfaces for receiving, transmitting, and/or otherwise communicating data and/or information in a network environment.

In various embodiments, storage <NUM> can be configured to store data, information and/or instructions associated with radio equipment controller <NUM> and/or logic configured for memory element(s) <NUM>. Note that in certain examples, storage <NUM> can be consolidated with memory elements <NUM> (or vice versa), and/or the storage/memory elements can overlap/exist in any other suitable manner.

In various embodiments, radio equipment controller logic <NUM> can include instructions that, when executed (e.g., by processor(s) <NUM>) cause radio equipment controller <NUM> to perform operations, which can include, but not be limited to: performing control, management, etc. operations associated with radio equipment controller <NUM> (e.g., CPRI link negotiation operations, radio equipment controller operations, and/or any other normal operations); cooperating and/or interacting with other logic (internal and/or external to radio equipment controller <NUM>) and/or network interface element(s) <NUM> (e.g., for CPRI link negotiation operations, radio equipment controller operations, and/or any other normal operations); maintaining and/or interacting with stored data, information, and/or parameters (e.g., link bit rates); combinations thereof; and/or the like to facilitate operations as discussed for various embodiments described herein.

In various embodiments, storage <NUM> may include any suitable storage such as persistent storage, which may be a magnetic disk drive, a solid state hard drive, a semiconductor storage device, ROM, EPROM, flash memory, or any other computer readable storage media, which may be inclusive of non-transitory tangible media and/or non-transitory computer readable storage media, that is capable of storing program/logic/software instructions and/or digital information. In some embodiments, the media used by storage <NUM> may also be removable. For example, a removable hard drive may be used for storage <NUM>. Other examples include optical and magnetic disks, thumb drives, and smart cards that are inserted into a drive for transfer onto another computer readable storage medium that is also part of storage <NUM>.

Referring to <FIG> is a simplified block diagram illustrating example details associated with a radio equipment <NUM> for implementing operations described herein, according to an example embodiment. In at least one embodiment, radio equipment <NUM> may provide operations associated with radio equipment within a fronthaul network as discussed herein such as, for example, RE <NUM> of fronthaul network <NUM>.

The embodiment of <FIG> illustrates radio equipment <NUM>, which includes one or more processor(s) <NUM>, one or more memory element(s) <NUM>, a bus <NUM>, one or more network interface element(s) <NUM>, storage <NUM>, and a radio head <NUM>. Memory element(s) <NUM> may include instructions for radio equipment logic <NUM>. In at least one embodiment, radio head <NUM> can include circuitry, hardware, antennas, software, firmware, combinations thereof, and/or the like to provide one or more radio transmitters and receivers to facilitate over-the-air radio access connectivity for user equipment.

In at least one embodiment, processor(s) <NUM> is/are at least one hardware processor configured to execute various tasks, operations, and/or functions for radio equipment <NUM> according to software and/or instructions configured for radio equipment <NUM>. In at least one embodiment, memory element(s) <NUM> is/are configured to store data, information, software and/or instructions associated with radio equipment <NUM> and logic configured for memory element(s) <NUM>. In at least one embodiment, bus <NUM> can be configured as an interface that enables one or more elements of radio equipment <NUM> (e.g., network interface element(s) <NUM>, processor(s) <NUM>, memory element(s) <NUM> (and logic, etc. configured therein), radio head <NUM>, etc.) to communicate in order to exchange information and/or data, to perform operations, etc. In at least one embodiment, a fast kernel-hosted interconnect may be employed for radio equipment <NUM>, potentially using shared memory between processes (e.g., logic, etc.), which can enable efficient communication paths between the processes.

In various embodiments, network interface element(s) <NUM> enables communications (wired or wireless) between radio equipment <NUM> and other network elements or nodes, via one or more input/output (I/O) elements <NUM> (e.g., any number/combination of CPRI ports, Ethernet ports, transceivers, etc.) at which data, information, etc. is received and transmitted to facilitate operations discussed for various embodiments described herein. In various embodiments, network interface element(s) <NUM> (e.g., hardware, software, firmware, logic, etc.) can be configured to include Ethernet interface elements, CPRI interface elements, RF interface elements (e.g., for WiFi or any other unlicensed spectrum communications, for 3GPP or any other licensed spectrum communications, and/or or any other similar network interface elements to enable communications for radio equipment <NUM> within a fronthaul network (e.g., fronthaul network <NUM>). Radio equipment <NUM> can include any suitable interfaces for receiving, transmitting, and/or otherwise communicating data and/or information in a network environment.

In various embodiments, storage <NUM> can be configured to store data, information and/or instructions associated with radio equipment <NUM> and/or logic configured for memory element(s) <NUM>. Note that in certain examples, storage <NUM> can be consolidated with memory elements <NUM> (or vice versa), and/or the storage/memory elements can overlap/exist in any other suitable manner.

In various embodiments, radio equipment logic <NUM> can include instructions that, when executed (e.g., by processor(s) <NUM>) cause radio equipment <NUM> to perform operations, which can include, but not be limited to: performing control, management, etc. operations associated with radio equipment <NUM> (e.g., CPRI link negotiation operations, radio equipment operations, and/or any other normal operations); cooperating and/or interacting with other logic (internal and/or external to radio equipment <NUM>) and/or network interface element(s) <NUM> (e.g., for CPRI link negotiation operations, radio equipment operations, and/or any other normal operations); maintaining and/or interacting with stored data, information, and/or parameters (e.g., link bit rates); combinations thereof; and/or the like to facilitate operations as discussed for various embodiments described herein.

In summary, presented herein are techniques that provide a method to achieve link auto-negotiation and establishment between an REC and RE in an Ethernet-based fronthaul network, in at least one embodiment. Due to the adoption of massive Multiple-Input Multiple-Output (MIMO) technologies and huge bandwidth requirements for <NUM> communication, current deployments for LTE, LTE-Advanced, LTE-Advanced Pro and new <NUM> technology based deployments need to move to packetized fronthaul based networks. The existing deployments of these technologies where CPRI technology is used for interconnection between REC and RE should also work in Ethernet-based packetized fronthaul networks, i.e., the CPRI streams need to be packetized and sent over the packet network towards the other CPRI end point in packets where the CPRI stream will be extracted again and passed to the actual CPRI end point (REC/RE). This may allow for better adoption of <NUM> in the already existing network deployments.

While, the IEEE <NUM> and IEEE <NUM> Specifications are the standards for packet-based fronthaul transport networks; these standards do not cover how end-to-end link negotiations can happen between REC and RE in the fronthaul networks. Embodiments herein provide techniques to solve this above gap. For example, a network operator can deploy CPRI-based REC and/or RE units of varied capabilities in fronthaul network and the techniques discussed for embodiments herein can be used to achieve end-to-end CPRI link synchronization, which otherwise would require static manual configurations at each CPRI interface which is error prone, inefficient at times, and not scalable. Through fast-sampling by Proxy Slave <NUM>, embodiments herein provide for the ability to achieve deterministic end-to-end CPRI link synchronization between the REC <NUM> and RE <NUM>.

In one form, a computer-implemented method is provided, which may include receiving, by a proxy node, a Common Public Radio Interface (CPRI) bit stream transmitted by a radio equipment controller, wherein the CPRI bit stream is transmitted within a transmit time interval of the radio equipment controller; and fast-sampling, by the proxy node, the CPRI bit stream to determine whether a hyper frame number synchronization with the radio equipment controller at a common matching link bit rate is achievable, wherein the fast-sampling comprises attempting to decode the received CPRI bit stream and achieve the hyper frame number synchronization for each of a plurality of link bit rates configured for a fast-sampling time period during at least one fast-sampling time interval configured for the proxy node. For the method, each fast-sampling time interval comprises one fast-sampling time period. In some instances, each fast-sampling time interval may include multiple fast-sampling time periods. The fast-sampling time interval may be between <NUM> seconds and <NUM> seconds. The transmit time interval of the radio equipment controller may be between <NUM> seconds and <NUM> seconds.

The method may further include, upon the proxy node achieving the hyper frame number synchronization with the radio equipment controller at a particular link bit rate, communicating the received CPRI bit stream and the particular link bit rate to another proxy node via a packet-based network. The particular link bit rate may be communicated using a value that indicates a link bit rate option associated with the particular link bit rate.

In another form, another computer-implemented method is provided, which may include performing, for one or more link bit rates of a plurality of link bit rates configured for a fronthaul network, Common Public Radio Interface (CPRI) Layer <NUM> link auto-negotiation operations to establish a CPRI link between a radio equipment controller and a radio equipment of the fronthaul network. The CPRI Layer <NUM> link auto-negotiation operations may include fast-sampling, by a proxy slave, a first CPRI bit stream transmitted by a radio equipment controller to achieve a hyper frame number synchronization with the radio equipment controller at a link bit rate, wherein the fast-sampling comprises attempting to achieve the hyper frame number synchronization for each of a plurality of link bit rates configured for a fast-sampling time period during at least one fast-sampling time interval configured for the proxy slave. Upon the proxy slave achieving the hyper frame number synchronization with the radio equipment controller, the method may include communicating the first CPRI bit stream and the link bit rate from the proxy slave to a proxy master. The method may further include transmitting, by the proxy master, the first CPRI bit stream to the radio equipment at the link bit rate and the radio equipment attempting to achieve a hyper frame number synchronization with the first CPRI bit stream. Upon the radio equipment achieving the hyper frame number synchronization, the method may include the radio equipment communicating a second CPRI bit stream to the proxy master at the link bit rate. Upon the proxy master achieving a hyper frame number synchronization with the radio equipment for the second CPRI bit stream transmitted by the radio equipment at the link bit rate, the method may include communicating the second CPRI bit stream from the proxy master to the proxy slave transmitting, by the proxy slave, the second CPRI bit stream to the radio equipment controller.

The CPRI Layer <NUM> link auto-negotiation operations are completed and the CPRI link is established between the radio equipment controller and the radio equipment when the radio equipment controller achieves a hyper frame number synchronization for the second CPRI bit stream transmitted by the proxy slave at a particular link bit rate. The CPRI Layer <NUM> link auto-negotiation operations are performed within one transmit time interval of the radio equipment controller. The CPRI Layer <NUM> link auto-negotiation operations may be repeated with the plurality of link bit rates until the radio equipment controller achieves the hyper frame number synchronization for the second CPRI bit stream transmitted by the proxy slave at the particular link bit rate.

Upon achieving the hyper frame number synchronization with the radio equipment controller, the proxy slave does not transmit to the radio equipment controller until the second CPRI bit stream is received from the proxy master. The first CPRI bit steam and the link bit rate may be communicated from the proxy slave to the proxy master using an Ethernet network and the second CPRI bit stream is communicated from the proxy master to the proxy slave using the Ethernet network. Upon the Layer <NUM> link auto-negotiation operations being completed, the proxy slave does not communicate the link bit rate to the proxy master. Communicating the link bit rate may include communicating a value indicating a link bit rate option associated with the link bit rate. The value indicating the link bit rate option may be included within a header of a Radio over Ethernet (RoE) frame that is encapsulated within an Ethernet frame. The value indicating the link bit rate option may be included within a sequence number field of the header. The value indicating the link bit rate option may be included within one to four bits of a sequence number field of the header.

The operations described herein may be identified based upon the application for which they are implemented in a specific embodiment. However, it should be appreciated that any particular operation nomenclature herein is used merely for convenience, and thus the embodiments should not be limited to use solely in any specific application identified and/or implied by such nomenclature.

The environment of the present embodiments may include any number of computer, compute node, network element, or other processing systems (e.g., client or end-user systems, server systems, etc.) and databases or other repositories arranged in any desired fashion, where the present embodiments may be applied to any desired type of computing environment (e.g., cloud computing, client-server, network computing, mainframe, stand-alone systems, etc.). The computer or other processing systems employed by the present embodiments may be implemented by any number of any personal or other type of computer or processing system (e.g., desktop, laptop, personal digital assistant (PDA), mobile devices, etc.), and may include any commercially available operating system and any combination of commercially available and custom software (e.g., machine learning software, etc.). These systems may include any types of monitors and input/output devices (e.g., keyboard, mouse, voice recognition, etc.) to enter and/or view information.

Note that in certain example implementations, operations as outlined herein may be implemented by logic encoded in one or more tangible media, which may be inclusive of non-transitory tangible media and/or non-transitory computer readable storage media (e.g., embedded logic provided in an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), in digital signal processing (DSP) instructions, firmware, software [potentially inclusive of object code and source code] to be executed by a processor, or other similar machine, etc.). In some of these instances, a memory element or storage can store data used for operations described herein. This includes memory elements or storage being able to store software, logic, code, and/or processor instructions that are executed to carry out operations described herein. A processor (e.g., a hardware processor) can execute any type of instructions associated with data to achieve the operations detailed herein. In one example, a processor may transform an element or an article (e.g., data, information) from one state or thing to another state or thing. In another example, operations outlined herein may be implemented with logic, which can include fixed logic, hardware logic, programmable logic, digital logic, etc. (e.g., software/computer instructions executed by a processor) and the elements identified herein could be some type of a programmable processor, programmable digital logic (e.g., an FPGA, a DSP processor, an EPROM, a controller, an electrically erasable PROM (EEPROM), or an ASIC that includes digital logic, software, firmware, code, electronic instructions, or any suitable combination thereof.

In one example implementation, a network element can encompass network appliances, routers, servers, switches, gateways, bridges, load balancers, firewalls, processors, modules, or any other suitable device, component, element, or object operable to exchange information that facilitates or otherwise helps to facilitate various operations as described for various embodiments discussed herein in a network environment (e.g., for networks such as discussed herein).

The above description is intended by way of example only. Although the techniques are illustrated and described herein as embodied in one or more specific examples, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made within the scope of the claims.

Elements and/or systems discussed for various embodiments described herein can couple to one another through simple interfaces and/or through any other suitable connection (wired or wireless), which provides a viable pathway for network communications. As referred to herein, a physical (wired or wireless) interconnection or interface can refer to an interconnection of one element with one or more other element(s), while a logical interconnection or interface can refer to communications, interactions and/or operations of elements with each other, which can be directly or indirectly interconnected, in a network environment. Additionally, any one or more of the elements and/or systems may be combined or removed from a given deployment based on a particular configuration and/or implementation.

In various embodiments, networks can represent a series of points or elements of interconnected communication paths (wired or wireless) for receiving and transmitting packets of information that propagate through networks. In various embodiments, networks can be associated with and/or provided by a single network operator or service provider and/or multiple network operators or service providers. In various embodiments, networks can include and/or overlap with, in whole or in part, one or more packet data network(s). A network may offer communicative interfaces between various elements of the network and may be associated with any local area network (LAN), wireless local area network (WLAN), metropolitan area network (MAN), wide area network (WAN), virtual private network (VPN), Radio Access Network (RAN), virtual local area network (VLAN), enterprise network, Intranet, extranet, or any other appropriate architecture or system that facilitates communications in a network environment.

Networks through which communications propagate in can use any suitable technologies for communication including wireless (e.g., <NUM>/<NUM>/<NUM>/NG network, Institute of Electrical and Electronics Engineers (IEEE) Standard <NUM>™-<NUM>, published March <NUM>, <NUM> (e.g., WiFi), WiMax, IEEE Standard <NUM>™-<NUM>, published August <NUM>, <NUM>, Radio-frequency Identification (RFID), Near Field Communication (NFC), Bluetooth™, etc.) and/or wired (e.g., T1 lines, T3 lines, digital subscriber lines (DSL), Ethernet, etc.) communication. Generally, any suitable means of communication may be used such as electric, sound, light, infrared, and/or radio.

Note that in this disclosure, references to various features (e.g., elements, structures, nodes, modules, components, logic, steps, operations, functions, characteristics, etc.) included in 'one embodiment', 'example embodiment', 'an embodiment', 'another embodiment', 'certain embodiments', 'some embodiments', 'various embodiments', 'other embodiments', 'alternative embodiment', and the like are intended to mean that any such features are included in one or more embodiments of the present disclosure, but may or may not necessarily be combined in the same embodiments. Note also that a module, engine, client, controller, function, logic, or the like as used herein, can be inclusive of an executable file comprising instructions that can be understood and processed on a computer, processor, machine, network element, compute node, combinations thereof, or the like and may further include library modules loaded during execution, object files, system files, hardware logic, software logic, and/or any other executable modules.

The embodiments presented may be implemented in various forms, such as an apparatus, a system, a method, and/or a computer program product at any possible technical detail level of integration. The computer program product may include a non-transitory computer readable storage medium (or media) having computer readable program instructions thereon for causing a processor to carry out aspects of operations presented herein.

It is also important to note that the operations and steps described with reference to the preceding figures illustrate only some of the possible scenarios that may be executed by, or within, a system or network. Some of these operations may be deleted or removed where appropriate, or these steps may be modified or changed considerably without departing from the scope of the discussed concepts. In addition, the timing of these operations may be altered considerably and still achieve the results taught in this disclosure. The preceding operational flows have been offered for purposes of example and discussion. Substantial flexibility is provided by the system in that any suitable arrangements, chronologies, configurations, and timing mechanisms may be provided without departing from the teachings of the discussed concepts.

Note that with the examples provided above, as well as numerous other examples provided herein, interactions may be described in terms of one, two, three, or four elements. However, this has been done for purposes of clarity and example only. In certain cases, it may be easier to describe one or more of the functionalities by only referencing a limited number of network elements. It should be appreciated that networks discussed herein (and their teachings) are readily scalable and can accommodate a large number of components, as well as more complicated/sophisticated arrangements and configurations. Accordingly, the examples provided should not limit the scope or inhibit the broad teachings of networks discussed herein as potentially applied to a myriad of other architectures.

As used herein, unless expressly stated to the contrary, use of the phrase 'at least one of, 'one or more of, 'and/or', variations thereof, or the like are open ended expressions that are both conjunctive and disjunctive in operation for any combination of named elements, conditions, or activities. For example, each of the expressions 'at least one of X, Y and Z', 'at least one of X, Y or Z', 'one or more of X, Y and Z', 'one or more of X, Y or Z' and 'A, B and/or C' can mean any of the following: <NUM>) X, but not Y and not Z; <NUM>) Y, but not X and not Z; <NUM>) Z, but not X and not Y; <NUM>) X and Y, but not Z; <NUM>) X and Z, but not Y; <NUM>) Y and Z, but not X; or <NUM>) X, Y, and Z. Additionally, unless expressly stated to the contrary, the terms 'first', 'second', 'third', etc., are intended to distinguish the particular nouns (e.g., element, condition, node, module, activity, operation, etc.) they modify. Unless expressly stated to the contrary, the use of these terms is not intended to indicate any type of order, rank, importance, temporal sequence, or hierarchy of the modified noun. For example, 'first X' and 'second X' are intended to designate two X elements that are not necessarily limited by any order, rank, importance, temporal sequence, or hierarchy of the two elements. Further as referred to herein, 'at least one of and 'one or more of can be represented using the '(s)' nomenclature (e.g., one or more element(s)).

Claim 1:
A method comprising:
receiving (<NUM>), by a proxy node, a Common Public Radio Interface, CPRI, bit stream transmitted by a radio equipment controller, wherein the CPRI bit stream is transmitted within a transmit time interval of the radio equipment controller;
oversampling (<NUM>), by the proxy node, the CPRI bit stream to determine (<NUM>) whether a hyper frame number synchronization with the radio equipment controller at a common matching link bit rate is achievable, wherein the oversampling comprises attempting to decode the received CPRI bit stream and achieve the hyper frame number synchronization for each of a plurality of link bit rates configured for a oversampling time period during at least one oversampling time interval configured for the proxy node; and
upon the proxy node achieving the hyper frame number synchronization with the radio equipment controller at a particular link bit rate, communicating (<NUM>) the received CPRI bit stream and the particular link bit rate to another proxy node via a packet-based network.