IEEE 1914.3-2018 pdf download

IEEE 1914.3-2018 pdf download.IEEE Standard for Radio over Ethernet Encapsulations and Mappings
The presentation time is relative to a reference plane, as shown in Figure 11 (in Clause 6) for the mapper and de-mapper, which is itself referenced to a timescale (see 6.2). Both the transmitting and receiving endpoints must be referenced to the same timescale for the information to be presented at the appropriate time. The ToD used for the presentation time mechanism shall be tracked with a 24-bit nanosecond counter and a 5-bit fractional nanosecond counter.
The presentation time counters at the associated endpoints shall be aligned so that their 29-bit ToD values are consistent (to a specified uncertainty) with the ToD of a counter that started at zero at the chosen common timescale’s epoch and that increments with that timescale’s definition of the duration of 1/32 ns. An example of how this alignment is achieved for a Precision Time Protocol (PTP) timescale is shown inAnnex C.
The format of the timeStamp field is shown in Figure 10.
Bit 0 is the start of frame (SoF) marker and is an indication of a radio frame boundary. An SoF bit is set to 1 indicates that the start of the payload field (not counting the rbMap field; see Figure 18 in 8.5.2) is the start of the radio frame.
An SoF bit is set to 0 indicates that the start of the payload is not the start of the radio frame. For data packets, the orderInfo value is the sequence number or timestamp that applies to the start of the RoE payload data (not counting the rbMap field; see Figure 18). Bit 1 and bit 2 contain the 2 least significant bits (LSBs) of the p-counter from the .seqNum information. Bit 3 to bit 26 of the timeStamp field is the integer nanosecond portion of the presentation timestamp. It counts in units of nanoseconds, and the value ranges from 0 ns to 16 777 215 ns (0x0 to 0xFF FFFF, respectively). Bit 27 to bit 31 of the timeStamp field is the fractional nanosecond portion of the presentation timestamp. It counts in fractions of a nanosecond (0.03125 ns) where 0x0 represents 0 ns and 0x1F represents 0.96875 ns. If sub-nanosecond timestamping is not used, these 5 bits shall be set to 0 at the sender and shall be ignored at the receiver. The size of the presentation timestamp permits the mapper to specify a presentation time that is up to 16 777 215.96875 ns in the future.
Under non-erroneous conditions, the presentation timestamp value shall correspond to the same absolute ToD value at the mapper and the de-mapper to the nanosecond level or better (the use of fractional nanoseconds bits is optional). Examples of how the presentation timestamp value is generated at the mapper and interpreted at the de-mapper for both non-erroneous and erroneous conditions are given inAnnex C. 5.5.6 Payload field The content, structure, and size of the payload field are specific to an RoE subtype and its definition.
The payload may contain a flow of I/Q samples for a single antenna carrier (AxC) or a group of AxCs. Both single and group content is identified by a flowID between two RoE nodes. Furthermore, when specific RoE mappers are applied, the payload field can contain, for example, an individual AxC component flow of a decomposed CPRI basic frame. For RoE control packets, the payload may contain appropriate C&M information,such as in the form of type-length-value (TLV) messages.
The total RoE payload field size shall consist of full octets.
RoE payloads shall have a minimum size of 64 B.
6. Timing and synchronization considerations
6.1 General
For an RoE interface to work, both ends of the link need some knowledge of time. To comply with radio requirements, the presentation time of the radio signal needs to be tightly controlled. See Figure 11. The mechanism for achieving this, however, is not specified by this standard.IEEE 1914.3 pdf download.IEEE 1914.3-2018 pdf download