ETSI TR 102 944 V1.1.1 (2011-07)

Reconfigurable Radio Systems (RRS); Use Cases for Baseband Interfaces for Unified Radio Applications of Mobile Device

DTR/RRS-02005

General Information

• Status: Published
• Publication Date: 21-Jul-2011
• Technical Committee: RRS 2 - REA - Reconfigurable Radio Equipment Architecture
• Current Stage: 12 - Completion
• Due Date: 25-Jul-2011
• Completion Date: 22-Jul-2011

Standards Content (Sample)

Technical Report
Reconfigurable Radio Systems (RRS);
Use Cases for Baseband Interfaces for
Unified Radio Applications of Mobile Device

2 ETSI TR 102 944 V1.1.1 (2011-07)

Reference
DTR/RRS-02005
Keywords
CRS, SDR
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3 ETSI TR 102 944 V1.1.1 (2011-07)
Contents
Intellectual Property Rights . 4
Foreword . 4
1 Scope . 5
2 References . 5
2.1 Normative references . 5
2.2 Informative references . 5
3 Definitions and abbreviations . 6
3.1 Definitions . 6
3.2 Abbreviations . 7
4 Information . 8
4.1 Background . 8
4.2 Hardware/Software Framework . 9
5 Use Cases . 11
5.1 Use Case 1: Fixed Pipeline . 11
5.2 Use Case 2: Programmable Pipeline . 12
5.2.1 Without the capability of User Defined Function Block. 12
5.2.2 With the capability of User Defined Function Block . 12
5.2.3 With additional capability for BBA to support the IR . 13
5.3 Use Case 3: Hybrid Pipeline. 14
5.4 Use Case 4: Context information processing . 15
6 Challenges . 17
7 Conclusion . 17
History . 19

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4 ETSI TR 102 944 V1.1.1 (2011-07)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (http://ipr.etsi.org).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This Technical Report (TR) has been produced by ETSI Technical Committee Reconfigurable Radio Systems (RRS).
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5 ETSI TR 102 944 V1.1.1 (2011-07)
1 Scope
The objective of the present document is to collect Use Cases that are needed for standardizing the BaseBand Interface
(BBI) of Mobile Device (MD) that enables the MD to be configured into various radio applications. The Use Cases to
be defined in the present document are related to the internal interface of Unified Radio Application (URA) which has
been defined in [i.1]. In order to support the flexible configuration of MD into various radio applications, a standard set
of baseband interfaces should be adopted in the URA of MD. Therefore, the present document suggests variety of Use
Cases related to the configuration method using the standard interface to be defined later in ETSI TC RRS. The present
document will suggest component level Use Cases not system level Use Cases, which particularly means that the Use
Cases to be specified in the present document are for supporting interoperations among baseband signal processing
modules inside MD which are needed for multiradio application configuration of MD which adopts the standard
baseband interface.
2 References
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the
referenced document (including any amendments) applies.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
NOTE: While any hyperlinks included in this clause were valid at the time of publication ETSI cannot guarantee
their long term validity.
2.1 Normative references
The following referenced documents are necessary for the application of the present document.
Not applicable.
2.2 Informative references
The following referenced documents are not necessary for the application of the present document but they assist the
user with regard to a particular subject area.
[i.1] ETSI TR 102 680 (V1.1.1): "Reconfigurable Radio Systems (RRS); SDR Reference Architecture
for Mobile Device".
[i.2] ETSI TR 102 839 (V1.1.1): "Reconfigurable Radio Systems (RRS); Multiradio Interface for
Software Defined Radio (SDR) Mobile Device Architecture and Services".
[i.3] ETSI TR 103 062 (V1.1.1): "Reconfigurable Radio Systems (RRS) Use Cases and Scenarios for
Software Defined Radio (SDR) Reference Architecture for Mobile Device".
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6 ETSI TR 102 944 V1.1.1 (2011-07)
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
radio application package: package containing Radio Controller (RC) code, user defined function block code, and
metadata needed for setting up and running radio application(s)
NOTE: RC code is downloaded into application processor while the user defined function block is downloaded
into baseband processor in accordance with the contents of the metadata. Metadata indicate which
function blocks are to be combined in what order for implementing given radio application(s) in the
baseband processor.
Radio Controller (RC): software component performing the following functions:
1) transferring context information from corresponding function block(s) in baseband processor to monitor;
2) transferring receive user data packet from Medium Access Control (MAC) buffer to networking stack; and
3) transferring transmit source data packet from networking stack to MAC buffer.
NOTE: An RC performs also upper layer processing of radio application that operates in non real-time. The
monitor, to which the context information is transferred, denotes an application that uses the context
information in non real-time such as Mobility Policy Manager (MPM). An RC, which operates in
application processor in non real-time, can access function block, which operates in baseband processor
in real-time, through driver which is prepared in application processor.
BaseBand Interface (BBI): interface consisting of a Radio Application Interface (RAI) and a Context Information
Interface (CII)
NOTE: RAI is for baseband signal processing and CII is for transferring the context information to monitor. BBI
includes:
1) function block definition of radio application;
2) interface among the function blocks;
3) interface between RC and each of corresponding function block(s).
function block: each modem function needed for real-time implementation of radio application(s)
NOTE: A function block includes not only the modem functions in Layer1 (L1), L2, and L3 but also all the
control functions that should be processed in real-time for implementing given radio application(s).
Function block is categorized into standard function block and user defined function block. In more
details:
1) Standard function block can be shared by many radio applications. For example, Forward Error
Correction (FEC), Fast Fourier Transform (FFT)/Inverse Fast Fourier Transform (IFFT),
(de)interleaver, Turbo coding, Viterbi coding, Multiple Input Multiple Output (MIMO),
Beamforming, etc are the typical category of standard function block.
2) User defined function block includes those function blocks that are dependent upon a specific radio
application. It is used to support special function(s) required in a specific radio application or to
support a special algorithm used for performance improvement. In addition, the user defined
function block can be used as baseband controller function block which is to control the function
blocks operating in baseband processor in real-time and to control some context information that
are to be processed in real-time such as Channel State Information (CSI).
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7 ETSI TR 102 944 V1.1.1 (2011-07)
driver: set of software components that includes installer, loader, back-end compiler or full compiler (if necessary),
standard function block pool (if necessary), and any other components needed for setting up and running radio
application(s)
NOTE: A driver provides the following functions as well:
1) enabling RC, which operates in application processor mostly in non real-time, to access each of
corresponding function block(s) operating in baseband processor in real-time;
2) back-end compiler for translating platform-independent IR into vendor assembly in the case of
using platform independent IR for user defined function block;
3) full compiler for compiling source code into vendor assembly in the case of using source code for
user defined function block;
4) installer for storing radio application package to storage device such as flash memory;
5) loader for loading RC code to application processor; and
6) loader for loading function block(s) code to baseband processor.
A driver which is provided by a modem chip manufacturer is prepared in application processor and
includes standard function blocks needed for the configuration of various radio applications. During the
configuration of radio application, RC is loaded in application processor and standard function blocks and
user defined function blocks are loaded in baseband processor in accordance with the contents of
metadata. It particularly means that Driver includes two loaders: one is to load RC in application
processor and the other is to load the function blocks in baseband processor. Although there are varieties
of modem chip vendors each of which has its own architecture and functioning in baseband processor, the
RC which operates in application processor can access each of corresponding function block(s) in
baseband processor using the driver which is provided in compliance with BBI by the modem chip
vendor.
Intermediate Representation (IR): code obtained as a result of compiling high level code with front-end compiler
NOTE: IR is a non-executable code and independent of baseband processor. It is a structural and behavioural
representation of radio application code. Since a user defined function block should be used in every kind
of modem chip, user defined function block in radio application package is provided in IR in mid- or
long-term scenario. The reason why user defined function block is to be provided in IR instead of
executable code is to resolve the portability problem existing in executable code. When user defined
function block is provided in IR (platform-independent), the user defined function block is translated into
vendor assembly which is executable in a specific baseband processor using back-end compiler that is
provided by modem chip manufacturer in the driver of application processor.
vendor assembly: code obtained as a result of compiling the IR with back-end compiler
NOTE: Vendor assembly is executable code and, thus, applicable only to a specific baseband processor. The
back-end compiler is provided by modem chip provider because vendor assembly has to be prepared for
each of baseband processors. In short, back-end compiler translates IR into vendor assembly, which can
be ported on a specific baseband processor for which the back-end compiler translates IR.
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
BB BaseBand
BBA BB Accelerator
BBI BB Interface
BPA Baseband Parameter Aggregation
CII Context Information Interface
CSI Channel State Information
FEC Forward Error Correction
FFT Fast Fourier Transform
GSM Global System for Mobile communications
IFFT Inverse Fast Fourier Transform
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8 ETSI TR 102 944 V1.1.1 (2011-07)
IR Intermediate Representation
LTE Long Term Evolution
MAC Medium Access Control
MD Mobile Device
MIMO Multiple Input Multiple Output
MPM Mobility Policy Manager
MURI MUltiRadio Interface
RAI Radio Application Interface
RC Radio Controller
RLC Radio Link Control
RRC Radio Resource Control
RRS Reconfigurable Radio System
RSSI Received Signal Strength Indication
SDR Software Defined Radio
TR Technical Report
URA Unified Radio Application
URAI Unified Radio Application Interface
WiMAX Worldwide Interoperability for Microwave Access
4 Information
4.1 Background
This clause describes the background and scope of Use Cases of BBI. Particularly, we are interested in how the Use
Cases to be discussed in the present document are related to the SDR architecture, Unified Radio Application Interface
(URAI), and Multiradio Interface (MURI), which are the main topics of [i.1] and [i.2], respectively.

Figure 1: Functional architecture of SDR equipment
In [i.1] and [i.2], the functional architecture of multiradio computer device has been shown as in Figure 1 that is based
on the multiradio computer concept. The BBIs are related to the interfaces mainly in the Unified Radio Application
(URA) shown in Figure 1 except the ones that are to be defined for transferring the context information.
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9 ETSI TR 102 944 V1.1.1 (2011-07)

Figure 2: Compile-time and run-time functions of Radio Computer
Figure 2 illustrates compile-time and run-time functions of radio computer [i.2]. According to the scenario shown in
Figure 2, radio program is built into radio package through radio compiler. Radio package contains not only the binary
code of the radio program components but also metadata about the radio system. The loader component of the radio
operating system will install and load radio packages into the execution environment of the radio computer. Use Cases
described in the present document follows the scenario shown in Figure 2. Particularly, the present document shows
Use Cases of the standard BB interface needed for the configuration of various radio applications focusing on baseband
signal processing modules of URA.
4.2 Hardware/Software Framework
This clause introduces hardware and software framework of baseband processor and application processor in MD that
are basis of BBI Use Cases to be provided in the present document.

Figure 3: Hardware and software structure of radio computer according to
radio application configuration
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Figure 3 illustrates hardware and software structure of radio computer set up as a result of radio application
configuration. It can be observed that the radio application configuration shown in Figure 3 is in accordance with the
radio computer concept shown in [i.2]. Radio application package contains RC code, user defined function block(s)
code and metadata. Radio application package that is prepared in compliance with the BBI is installed in a storage and
loaded by installer and loader, respectively. RC is loaded in application processor which operates in most cases in non
real-time. RC controls transmitting and receiving user data packet. It also transfers context information to monitor for
MPM to refer to it. Function blocks are loaded in baseband processor which operates in real-time. Standard function
blocks which are installed in driver are loaded in baseband processor together with user defined function block which
was included in radio application package. Note that user defined function block should be translated into vendor
assembly before loading in baseband processor because radio application package provides it in platform-independent
IR. Loader refers to the contents of metadata when it loads the function blocks in baseband processor.
Depending on the radio computer deployment scenarios as detailed in clause 5.4 of [i.2], the translation of function
blocks into vendor assembly may be performed off-line by the vendor delivering executable, platform-specific code to
the mobile devices or by translating platform-independent code into platform-specific code by the back-end compiler on
th
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