ORAN协议v05.00：O-RAN WG4.CUS.0-v05.00技术规范

需积分: 0 144 浏览量更新于2024-01-02 收藏 10.62MB PDF 举报

ORAN协议是O-RAN ALLIANCE发布的一项技术规范，最新版本为v05.00。该规范由O-RAN前传工作组（Fronthaul Working Group）负责制定，主要涵盖了控制、用户和同步平面相关的技术要求。首先，该协议的版权归O-RAN ALLIANCE e.V所有，未经授权不得使用、访问或下载其中的任何部分。用户若使用、复制、保存、分发、展示或准备该规范的衍生作品，则视为同意并受到该规范中附带的O-RAN采纳者许可协议的条款约束。协议声明保留一切其他权利。 ORAN协议的最新版本为v05.00，主要关注控制、用户和同步平面的技术规范。这意味着该协议提供了一套详细的规定，以确保ORAN系统在控制信令传输、用户数据传输和时钟同步等方面的高效性和可靠性。该规范在控制平面方面，确保了ORAN系统的控制信令的正确传输和处理。这包括定义了传输介质、信令参数、信令格式和相关协议等方面的技术要求，以确保控制信令的高效交互和可靠性。在用户平面方面，ORAN协议规定了用户数据的传输要求和特性。这包括对传输介质、数据格式、数据传输速率和相关协议等方面的详细规定，以确保用户数据的高速传输和可靠性。同时，在时钟同步平面方面，ORAN协议规范了时钟同步的要求和机制。这涵盖了时钟同步的传输介质、时钟源、时钟同步算法和时钟精度等方面的规定，以确保ORAN系统中各个节点的时钟同步性能。值得注意的是，ORAN协议的v05.00版本是过去一段时间内的最新发布版本。该版本可能包含了之前版本的改进和更新，以修正已知的问题和提高系统的性能。总结来说，ORAN协议v05.00是O-RAN ALLIANCE发布的一项技术规范，主要涉及控制、用户和同步平面的技术要求。该协议规定了控制信令的传输和处理、用户数据的传输和特性，以及时钟同步的要求和机制。通过遵循该协议，可以确保ORAN系统在控制、用户和同步方面的高效性和可靠性。

________________________________________________________________________________________________

Your use is subject to the terms of the O-RAN Adopter License Agreement in the Annex ZZZ. 16

O-RAN.WG4.CUS.0-v05.00

1.3.2 Abbreviations

For the purposes of the present document, the abbreviations given in 3GPP TR 21.905 [1] and the following apply. An

abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in

3GPP TR 21.905 [1].

eNB e NodeB (applies to LTE)

FHM Fronthaul Multiplexer

gNB g NodeB (applies to NR)

O-DU O-RAN Distributed Unit (see definitions section)

O-RU O-RAN Radio Unit

SMO Service Management and Orchestration

1.3.3 Document Conventions

Terminology: “ignored”

Within this specification, it is sometimes stated that certain information elements are to be “ignored” by the receiver

(generally for “reserved” fields but in some cases other fields too). In this case, the fields shall be ignored for the

purposes of processing at the O-RAN application level, but in the case of certain packet error-checking such as

Ethernet-layer CRC or parity calculations, the fields shall be included in the CRC or parity calculations. As well, in the

event of packet encryption, the “ignored” fields shall be encrypted along with the other packet payload information.

1.3.3.1 Fields and Bitmasks in Messages

This document describes the format of several messages and data structures within messages.

Notation “X[k]” represents k

bit in a field X. Note bit X[0] is the least significant bit of field X. Where applicable, a

sequence of bits in a field X can be interpreted as an unsigned integer value 



calculated with formula:





󰇟󰇠





where N is number of bits in field X.

Notation “X[a:b]” represents a sequence of bits in field X starting from bit X[a] and ending at bit X[b] inclusive.

The tables describing formats of messages and data structures use a notation of which an example is presented in Table

1-1.

Table 1-1 Example of table presenting format of a data structure

0 (msb)

7 (lsb)

# of

bytes

octet

Y[3:0]

X[11:8]

X[7:0]

N+1

The example data structure presented in Table 1-1 is interpreted as follows:

• Field Y has 4 bits. Bits Y[3] to Y[0] of field Y are in octet N; Y[3] - the most significant bit of field Y is in the

most significant bit of octet N.

• Field X has 12 bits. Bits X[11] to X[8] of field X are in octet N; X[8] - is in the least significant bit of octet N.

Bits X[7] to X[0] of field X are in octet N+1; X[7] - is in the most significant bit of octet N+1 and X[0] is in

the least significant bit of octet N+1.

This corresponds to a structure that maps every bit as presented in Table 1-2 below.

________________________________________________________________________________________________

Your use is subject to the terms of the O-RAN Adopter License Agreement in the Annex ZZZ. 18

O-RAN.WG4.CUS.0-v05.00

Chapter 2 Architecture & Requirements

Architectural aspects

The architecture of eNB or gNB with O-DU and O-RUs is shown in Figure 2-1. LLS-C and LLS-U provide C-plane

and U-plane over LLS interface, respectively.

In this architecture, O-DU and O-RU can be defined as follows.

Lower Layer Split Central Unit (O-DU): a logical node that includes the eNB/gNB functions as listed in section 2.1

split option 7-2x, excepting those functions allocated exclusively to the O-RU. The O-DU controls the operation of O-

RUs.

O-RAN Radio Unit (O-RU): a logical node that includes a subset of the eNB/gNB functions as listed in section 2.1

split option 7-2x. The real-time aspects of control & user plane communication with the O-RU are controlled by the O-

DU.

O-DU

LLS-C

O-RU O-RU

LLS-U

LLS-C LLS-U

eNB/gNB

...

Figure 2-1 : eNB/gNB architecture with O-DU and O-RUs

2.1 Functional Split

When considering the functional split defining a fronthaul interface there are two competing interests:

a) There is a benefit in keeping an O-RU as simple as possible because size, weight, and power draw are primary

deciding considerations and the more complex an O-RU, the larger, heavier and more power-hungry the O-RU

tends to be;

b) There is a benefit in having the interface at a higher level which tends to reduce the interface throughput

relative to a lower-level interface – but the higher-level the interface, the more complex the O-RU tends to be.

To resolve this conundrum, O-RAN has selected a single split point, known as “7-2x” but allows a variation, with the

precoding function to be located either “above” the interface in the O-DU or “below” the interface in the O-RU. For the

most part the interface is not affected by this decision, but there are some impacts namely to provide the necessary

information to the O-RU to execute the precoding operation. O-RUs within which the precoding is not done (therefore

of lower complexity) are called “Category A” O-RUs while O-RUs within which the precoding is done are called

“Category B” O-RUs. See Figure 2-2 for a depiction of this dual O-RU concept.

________________________________________________________________________________________________

Your use is subject to the terms of the O-RAN Adopter License Agreement in the Annex ZZZ. 19

O-RAN.WG4.CUS.0-v05.00

RE Mapping

Layer Mapping

Modulation

Scrambling

IQ Compression

O-DU

O-RU

Processing blocks with dotted blocks are not mandatory

for all O-RU categories. Precoding operation for certain

O-RU categories can be done within the O-RU and in this

case precoding in O-DU can be bypassed.

Non-precoding O-RAN

Radio Unit. Precoding in

radio is not supported.

O-RU Category A

Precoding O-RAN Radio

Unit. Precoding in radio is

supported.

Allows support for

modulation compression.

O-RU Category B

Digital Beamforming

iFFT and CP addition

Digital to Analog

Analog Beamforming

IQ Decompression

Digital and Analog

beamforming optional

Digital and Analog

beamforming optional

Precoding

(bypass mode possible)

O-RAN FH

Figure 2-2 : Split Point and Category A and Category B O-RAN Radio Units

The inclusion of these two O-RU categories has certain implications for the LTE and NR functional splits in both DL

and UL which are reflected in the following sections. In particular, for a Category B O-RU to implement precoding for

LTE TM2-TM4 some special C-Plane instructions need to be provided to the O-RU from the O-DU; this is described in

a later section of this document. For LTE TM5-10 and NR, no special instructions are needed because the precoding

may be included in a digital beamforming processing block within the O-RU for a Category B O-RU (even for analog

beamforming O-RUs), while for a Category A O-RU, the precoding would be executed in the O-DU and any

beamforming in the O-RU, if present, would exclude the precoding calculation.

2.1.1 Selected Split 7-2x (DL)

DL functional split for various physical layer channels is illustrated in Figure 2-3 (LTE Category A O-RUs), Figure

2-4 (LTE Category B O-RUs), Figure 2-5 (NR Category A O-RUs), and Figure 2-6 (NR Category B O-RUs).

When O-RU Category A is supported by O-DU it is mandatory to support a total number of precoded streams of up to

8. Support for more than 8 precoded streams is optional.

For LTE (e.g. TM9) and NR PDSCH with UE specific reference signals, the DL processing chain specified by 3GPP

does not include a precoding operation. The detailed precoding operation referred to in Figure 2-3 and Figure 2-4 for

PDSCH with UE specific reference signals is not further described within this specification.

剩余290页未读，继续阅读

hoududubaba

粉丝: 2469
资源: 13

ORAN协议v05.00：O-RAN WG4.CUS.0-v05.00技术规范

O-RAN.WG4.MP.0-v03.00.pdf

O-RAN-WG4.CUS.0-v07.00.pdf

ORAN-WG4.CUS.0-v03.00

ORAN协议 v04.00

"ORAN协议 v04.00——前传工作组技术规范

ORAN-WG4_ORAN-WG4.CUS_ORAN协议_oran.zip

ORAN-WG4.MP.0-v02.00.00.docx

ORAN-WG4.MP.0-v02.00.00.pdf

ORAN-WG4.CUS.0-v02.00.pdf

ORAN-WG4.MP-YANGs-v02.00.rar

最新资源