Open Base Station Architecture Initiative

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Open Base Station Architecture Initiative
Open Base Station Architecture Initiative logo.jpg
AbbreviationOBSAI
Formation2002
TypeTrade group
PurposeInterface standards
Website www.obsai.com

The Open Base Station Architecture Initiative (OBSAI) was a trade association created by Hyundai, LG Electronics, Nokia, Samsung and ZTE in September 2002 with the aim of creating an open market for cellular network base stations. The hope was that an open market would reduce the development effort and costs traditionally associated with creating base station products.

Hyundai Group is a South Korean conglomerate founded by Chung Ju-yung. The first company in the group was founded in 1947 as a construction company. With government assistance, Chung and his family members rapidly expanded into various industries, eventually becoming South Korea's second Enterprise Group. The company spun off many of its better known businesses after the 1997 Asian financial crisis, including Hyundai Automotive Group, Hyundai Department Store Group, and Hyundai Heavy Industries Group. Chung Ju-yung was directly in control of the company until his death in 2001.

LG Electronics South Korean multinational electronics company

LG Electronics Inc. is a South Korean multinational electronics company headquartered in Yeouido-dong, Seoul, South Korea.

Nokia Finnish technology corporation

Nokia Corporation is a Finnish multinational telecommunications, information technology, and consumer electronics company, founded in 1865. Nokia's headquarters are in Espoo, in the greater Helsinki metropolitan area. In 2018, Nokia employed approximately 103,000 people across over 100 countries, did business in more than 130 countries, and reported annual revenues of around €23 billion. Nokia is a public limited company listed on the Helsinki Stock Exchange and New York Stock Exchange. It is the world's 415th-largest company measured by 2016 revenues according to the Fortune Global 500, having peaked at 85th place in 2009. It is a component of the Euro Stoxx 50 stock market index.

Contents

Goal

The OBSAI specifications provided the architecture, function descriptions and minimum requirements for integration of a set of common modules into a base transceiver station (BTS). It:

Base transceiver station

A base transceiver station (BTS) is a piece of equipment that facilitates wireless communication between user equipment (UE) and a network. UEs are devices like mobile phones (handsets), WLL phones, computers with wireless Internet connectivity. The network can be that of any of the wireless communication technologies like GSM, CDMA, wireless local loop, Wi-Fi, WiMAX or other wide area network (WAN) technology.

GSM standard to describe protocols for second generation digital cellular networks used by mobile phones

The Global System for Mobile Communications (GSM) is a standard developed by the European Telecommunications Standards Institute (ETSI) to describe the protocols for second-generation (2G) digital cellular networks used by mobile devices such as mobile phones and tablets. It was first deployed in Finland in December 1991.By the mid-2010s, it became a global standard for mobile communications achieving over 90% market share, and operating in over 193 countries and territories.

Enhanced Data rates for GSM Evolution (EDGE) is a digital mobile phone technology that allows improved data transmission rates as a backward-compatible extension of GSM. EDGE is considered a pre-3G radio technology and is part of ITU's 3G definition. EDGE was deployed on GSM networks beginning in 2003 – initially by Cingular in the United States.

CDMA2000

CDMA2000 is a family of 3G mobile technology standards for sending voice, data, and signaling data between mobile phones and cell sites. It is developed by 3GPP2 as a backwards-compatible successor to second-generation cdmaOne (IS-95) set of standards and used especially in North America and South Korea.

This was intended to provide the BTS integrator with flexibility. A version 2.0 system reference document was published in 2006. [1]

BTS structure

The OBSAI Reference Architecture defines four functional blocks, interfaces between them, and requirements for external interfaces.

Functional blocks

A base transceiver station (BTS) has four main blocks or logical entities: Radio Frequency (RF) block, Baseband block, Control and Clock block, and Transport block.

Baseband signal that has a very narrow frequency range near zero

Baseband is a signal that has a near-zero frequency range, i.e. a spectral magnitude that is nonzero only for frequencies in the vicinity of the origin and negligible elsewhere. In telecommunications and signal processing, baseband signals are transmitted without modulation, that is, without any shift in the range of frequencies of the signal. Baseband has a low-frequency—contained within the bandwidth frequency close to 0 hertz up to a higher cut-off frequency. Baseband can be synonymous with lowpass or non-modulated, and is differentiated from passband, bandpass, carrier-modulated, intermediate frequency, or radio frequency (RF).

The Radio Frequency Block sends and receives signals to/from portable devices (via the air interface) and converts between digital data and antenna signal. Some of the main functions are D/A and A/D conversion, up/down conversion, carrier selection, linear power amplification, diversity transmit and receive, RF combining and RF filtering.

Digital data, in information theory and information systems, is the discrete, discontinuous representation of information or works. Numbers and letters are commonly used representations.

In telecommunications, a diversity scheme refers to a method for improving the reliability of a message signal by using two or more communication channels with different characteristics. Diversity is mainly used in radio communication and is a common technique for combatting fading and co-channel interference and avoiding error bursts. It is based on the fact that individual channels experience different levels of fading and interference. Multiple versions of the same signal may be transmitted and/or received and combined in the receiver. Alternatively, a redundant forward error correction code may be added and different parts of the message transmitted over different channels. Diversity techniques may exploit the multipath propagation, resulting in a diversity gain, often measured in decibels.

The Baseband Block processes the baseband signal. The functions include encoding/decoding, ciphering/deciphering, frequency hopping (GSM), spreading and Rake receiver (WCDMA), MAC (WiMAX), protocol frame processing, MIMO etc.

The Transport Block interfaces to external network, and provides functions such as QoS, security functions and synchronization.

Coordination between these three blocks is maintained by the Control and Clock Block.

Internal interfaces

Internal interfaces between the functional blocks are called reference points (RP).

RP1 is the interface that allows communication between the control block and the other three blocks. It includes control and clock signals. RP1 specification also specifies UDPCP - a UDP based reliable communication protocol. A version 2.1 of the reference point 1 interface was published in 2008. [2]

RP2 provides a link between the transport and baseband blocks. Version 2.1 of the reference point 2 interface was published in 2008. [3]

RP3 is the interface between baseband block and RF block. RP3-01 is an (alternate) interface between Local Converter and Remote RF block. Version 4.2 of the reference point 3 interface was published in 2010. [4]

RP4 provides the DC power interface between the internal modules and DC power sources. Version 1.1 of the reference point 4 interface was published in 2010. [5]

Most of the industry at the time revolved around achieving lower cost RF modules and power amplifiers (PA), as these two components usually account for nearly 50 percent of the BTS cost. Consequently, OBSAI works to define reference point 3 (RP3) prior to the other reference points to promote more competitive sources in the RF module and PA market.

External interfaces

Transport Block provides external network interface to operator network. Examples are: (lub) to the Radio Network Controller (RNC) for 3GPP systems, R6 to the Access Services Network Gateway (centralized Gateway) or R3 to Connectivity Services Network (CSN) for WiMAX systems.

RF Block provides external radio interface to subscriber devices. Examples are Uu or Um to the user equipment (UE) for 3GPP systems or R1 for WiMAX.

See also

Common Public Radio Interface (CPRI), an alternative, competing, standard.

Related Research Articles

General Packet Radio Service (GPRS) is a packet oriented mobile data standard on the 2G and 3G cellular communication network's global system for mobile communications (GSM). GPRS was established by European Telecommunications Standards Institute (ETSI) in response to the earlier CDPD and i-mode packet-switched cellular technologies. It is now maintained by the 3rd Generation Partnership Project (3GPP).

The Universal Mobile Telecommunications System (UMTS) is a third generation mobile cellular system for networks based on the GSM standard. Developed and maintained by the 3GPP, UMTS is a component of the International Telecommunications Union IMT-2000 standard set and compares with the CDMA2000 standard set for networks based on the competing cdmaOne technology. UMTS uses wideband code division multiple access (W-CDMA) radio access technology to offer greater spectral efficiency and bandwidth to mobile network operators.

Software-defined radio radio communication system implemented in software

Software-defined radio (SDR) is a radio communication system where components that have been traditionally implemented in hardware are instead implemented by means of software on a personal computer or embedded system. While the concept of SDR is not new, the rapidly evolving capabilities of digital electronics render practical many processes which were once only theoretically possible.

Medium access control a service layer in IEEE 802 network standards

In IEEE 802 LAN/MAN standards, the medium access control (MAC) sublayer is the layer that controls the hardware responsible for interaction with the wired, optical or wireless transmission medium. The MAC sublayer and the logical link control (LLC) sublayer together make up the data link layer. Within the data link layer, the LLC provides flow control and multiplexing for the logical link, while the MAC provides flow control and multiplexing for the transmission medium.

The 3rd Generation Partnership Project (3GPP) is a standards organization which develops protocols for mobile telephony. Its best known work is the development and maintenance of:

WiMAX wireless broadband standard

WiMAX is a family of wireless broadband communication standards based on the IEEE 802.16 set of standards, which provide multiple physical layer (PHY) and Media Access Control (MAC) options.

The GPRS core network is the central part of the general packet radio service (GPRS) which allows 2G, 3G and WCDMA mobile networks to transmit IP packets to external networks such as the Internet. The GPRS system is an integrated part of the GSM network switching subsystem.

Base station subsystem The section of a cellular telephone network responsible for handling traffic and signaling

The base station subsystem (BSS) is the section of a traditional cellular telephone network which is responsible for handling traffic and signaling between a mobile phone and the network switching subsystem. The BSS carries out transcoding of speech channels, allocation of radio channels to mobile phones, paging, transmission and reception over the air interface and many other tasks related to the radio network.

Customized Applications for Mobile networks Enhanced Logic (CAMEL) is a set of standards designed to work on either a GSM core network or the Universal Mobile Telecommunications System (UMTS) network. The framework provides tools for operators to define additional features for standard GSM services/UMTS services. The CAMEL architecture is based on the Intelligent Network (IN) standards, and uses the CAP protocol. The protocols are codified in a series of ETSI Technical Specifications.

PHY (chip) integrated circuit that implements functions of the physical layer in the OSI model

A PHY, an abbreviation for "physical layer", is an electronic circuit, usually implemented as a chip, required to implement physical layer functions of the OSI model.

Medium Attachment Unit

A Medium Attachment Unit (MAU) is a transceiver which converts signals on an Ethernet cable to and from Attachment Unit Interface (AUI) signals.

Universal Software Radio Peripheral Product family of software-defined radios

Universal Software Radio Peripheral (USRP) is a range of software-defined radios designed and sold by Ettus Research and its parent company, National Instruments. Developed by a team led by Matt Ettus, the USRP product family is intended to be a comparatively inexpensive hardware platform for software radio, and is commonly used by research labs, universities, and hobbyists.

Node B

Node B is the telecommunications node in particular mobile communication networks, namely those that adhere to the UMTS standard. The Node B provides the connection between mobile phones (UEs) and the wider telephone network. UMTS is the dominating 3G standard.

Communications servers are open, standards-based computing systems that operate as a carrier-grade common platform for a wide range of communications applications and allow equipment providers to add value at many levels of the system architecture.

OpenBTS

OpenBTS is a software-based GSM access point, allowing standard GSM-compatible mobile phones to be used as SIP endpoints in Voice over IP (VoIP) networks. OpenBTS is open-source software developed and maintained by Range Networks. The public release of OpenBTS is notable for being the first free-software implementation of the lower three layers of the industry-standard GSM protocol stack. It is written in C++ and released as free software under the terms of version 3 of the GNU Affero General Public License.

The Um interface is the air interface for the GSM mobile telephone standard. It is the interface between the mobile station (MS) and the Base transceiver station (BTS). It is called Um because it is the mobile analog to the U interface of ISDN. Um is defined in the GSM 04.xx and 05.xx series of specifications. Um can also support GPRS packet-oriented communication.

SIMCom

SIMCom Wireless Solutions is a subsidiary of SIM Technology Group Ltd. It is a fast-growing wireless M2M company, designing and offering a variety of wireless modules based on GSM/GPRS/EDGE, WCDMA/HSDPA and TD-SCDMA technical platforms

Remote radio head

A remote radio head (RRH), also called a remote radio unit (RRU) in wireless networks, is a remote radio transceiver that connects to an operator radio control panel via electrical or wireless interface. When used to describe aircraft radio cockpit radio systems, the control panel is often called the radio head.

C-RAN (Cloud-RAN), sometimes referred to as Centralized-RAN, is an architecture for cellular networks. It was first introduced by China Mobile Research Institute in April 2010 in Beijing, China, 9 years after it was disclosed in patent applications filed by U.S. companies. Simply speaking, C-RAN is a centralized, cloud computing-based architecture for radio access networks that supports 2G, 3G, 4G and future wireless communication standards. Its name comes from the four 'C's in the main characteristics of C-RAN system, "Clean, Centralized processing, Collaborative radio, and a real-time Cloud Radio Access Network".

References

  1. ↑ "BTS System Reference Document Version 2.0" (PDF). Open Base Station Architecture Initiative. November 14, 2006. Retrieved August 16, 2013.
  2. ↑ "Reference Point 1 Specification V2.1" (PDF). Open Base Station Architecture Initiative. July 14, 2008. Retrieved August 16, 2013.
  3. ↑ "Reference Point 2 Specification V2.1" (PDF). Open Base Station Architecture Initiative. July 14, 2008. Retrieved August 16, 2013.
  4. ↑ "Reference Point 3 Specification V4.2" (PDF). Open Base Station Architecture Initiative. March 18, 2010. Retrieved August 16, 2013.
  5. ↑ "Reference Point 4 Specification V1.1" (PDF). Open Base Station Architecture Initiative. November 14, 2006. Retrieved January 26, 2017.
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