IEEE 1900.4 WG on Architecture and Enablers for Optimized Radio & Spectrum Resource Usage Overview of IEEE 1900.4 Standard and P1900.4.1 and P1900.4a Draft Standards

Stanislav Filin, Hiroshi Harada, Homare Murakami, Kentaro Ishizu, and Goh Miyamoto National Institute of Information and Communications Technology (NICT)

Yokosuka, Japan {sfilin, harada, homa, ishidu, miyamoto}@nict.go.jp

Abstract— In general, cognitive radio system (CRS) can be viewed as a radio system using technology that allows it to obtain knowledge of its operational environment, established policies and its internal state; dynamically and autonomously adjust its operational parameters and protocols according to the obtained knowledge and predefined objectives; and to learn from the results obtained. Given such definition many use cases and business cases are possible, including heterogeneous type CRS, spectrum sharing type CRS, and dynamic spectrum assignment type CRS. As a result, several standardization activities have been performed recently to enable such use cases and exploit the corresponding business opportunities. One of such standardization has been performed within the IEEE 1900.4 Working Group (WG) on “Architecture and Enablers for Optimized Radio & Spectrum Resource Usage.” In February 2009, the first IEEE standard defining CRS has been published originating from the IEEE 1900.4 WG and entitled “Architectural Building Blocks Enabling Network-Device Distributed Decision Making for Optimized Radio Resource Usage in Heterogeneous Wireless Access Networks.” This paper gives technical overview of this standard. Also, it describes ongoing activities in the IEEE 1900.4 WG aimed at developing two draft standards: P1900.4.1 for “Interfaces and Protocols Enabling Distributed Decision Making for Optimized Radio Resource Usage in Heterogeneous Wireless Networks” and P1900.4a for “Architecture and Interfaces for Dynamic Spectrum Access Networks in White Space Frequency Bands.”1

Keywords-component; formatting; style; styling; insert (key words)

I. INTRODUCTION

Current wireless environment is characterized by its heterogeneity, as illustrated in Figure 1. Such heterogeneous wireless environment includes multiples operators each operating one or several radio access networks (RAN). These RANs can use different radio access technologies (RAT) to provide wireless services to their users. Also, users may use different RATs to communicate with each other in an ad-hoc mode.

1 The views presented in this paper are those of the authors and do not

necessarily reflect the views of IEEE SCC 41 or IEEE 1900.4 WG. This research was conducted under a contract of R&D for radio resource

enhancement, organized by the Ministry of Internal Affairs and Communications, Japan.

RAN 1

RAN 2

RAN 3

RAN 4

Figure 1. Heterogeneous wireless environment.

Component RANs of heterogeneous wireless environment are of different nature. They include cellular networks operating such RATs as GSM and WCDMA; WiFi hot spots; WiMAX wide area networks; and TV broadcast networks. To communicate with each other, users may use such RATs as Bluetooth and WiFi.

From the radio equipment point of view, different types of base stations (BS) and terminals are currently available on the market and are in use. While some BSs and terminals are designed to operate using a particular RAT, others have reconfiguration capabilities. Reconfigurable BSs can reconfigure themselves to use different RATs, for example, GSM, WCDMA, and Mobile WiMAX. In addition to reconfiguration, terminals may have a capability to support several wireless links in parallel.

From the spectrum usage point of view, component RANs have different frequency bands allocated for their operation. Various RATs could be detected in the frequency range between 400 MHz and 6 GHz. Also, usage of these frequency bands varies a lot in time and region. The main reasons for this are difference in the provided services and in the behavior of users consuming these services.

The described heterogeneous wireless environment has a lot of technical and business opportunities. The examples are: joint management of several RANs within one operator to balance load of these RANs; detecting and using unused spectrum in the allocated frequency bands without interrupting the operation of the primary users of such frequency bands; spectrum trading between several operators.

To exploit such opportunities, the concept of cognitive radio system (CRS) has been developed. In general CRS can be

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characterized as “a radio system employing technology that allows the system: to obtain knowledge of its operational and geographical environment, established policies and its internal state; to dynamically and autonomously adjust its operational parameters and protocols according to its obtained knowledge in order to achieve predefined objectives; and to learn from the results obtained” [1]. Given such definition many use cases and business cases are possible, including heterogeneous type CRS, spectrum sharing type CRS, and dynamic spectrum assignment type CRS, as illustrated in Figure 2.

RAT 5 RAT 6

Frequency band 4

Frequency band 5

RAT 3 RAT 4

Frequency band 3

RAT 1

Frequency band 1

RAT 2

Frequency band 2

Dynamic spectrum assignment type CRS

Frequency sharing type CRS

Heterogeneous type CRS

Figure 2. Types of cognitive radio system.

In heterogeneous type CRS, one or several operators operate several RANs using same or different RATs. Frequency bands assigned to these RANs are fixed. Also, reconfiguration of radio equipment on network side is not considered. These RANs provide services to their users, which use different terminals. One type of terminals is legacy terminals, designed to use a particular RAT. Such terminals can connect to one particular operator or to other operators having roaming agreements with the home operator. Another type of terminals is reconfigurable terminals. Such terminals have capability to reconfigure themselves to use different RATs. Correspondingly, such terminals can handover between different RANs using different RATs and operated by different operators. Optionally, reconfigurable terminals can support multiple simultaneous links with RANs.

Reconfiguration capabilities of terminals in heterogeneous type CRS provide one aspect of CRS – ability to reconfigure parameters a protocols of these terminals. However, two more aspects are required: obtaining knowledge of operational environment and intelligent decision making. To enable these two aspects, additional components need to be introduced in the heterogeneous type CRS.

One effort to define such components has been done by the IEEE 802.21 Working Group (WG), which has described media independent handover function to support handover between different RANs within a heterogeneous wireless network. The IEEE standard 802.21 was published in January 2009 [2].

In spectrum sharing type CRS several RANs using same or different RATs can share the same frequency band. One example of this type of CRS is when several RANs operate in

unlicensed spectrum. In this example CRS features can enable coexistence of such systems. Another example is when a secondary system operates in white space of a TV broadcast operator frequency band. In such example, CRS features should provide protection of primary service (TV broadcast) and coexistence between secondary systems.

An effort to define secondary CRS able to operate in TV white space is currently undergoing in IEEE 802.22 WG [3]. Draft standard P802.22 for “Cognitive Wireless Regional Area Network Medium Access Control (MAC) and Physical (PHY) Layer Specifications: Policies and Procedures for Operation in the TV Bands” is not finalized yet. As long as P802.22 is designed to support only fixed users, IEEE 802.22 WG is currently preparing P80.22a project authorization request to start standardization of secondary mobile wireless access system operating in TV white space.

In dynamic spectrum assignment type CRS one or several operators operate several RANs using same or different RATs in different frequency bands. To improve radio resource usage, configuration of these frequency bands can be dynamically changed. One example application of such type of CRS is joint management of several RANs within one operator, where spectrum allocated to this operator is dynamically redistributed between its RANs. Another example is spectrum trading between different operators.

All considered types of CRS have one common element – intelligent management system, which has three key features enabling:

Obtaining knowledge about operational environment,

Making intelligent decisions on reconfiguration of radio equipment on network and terminal sides according to obtained knowledge and some predefined objectives,

Controlling reconfiguration of radio equipment corresponding to the decisions made.

The IEEE 1900.4 WG was established in February 2007 to standardize such intelligent management system. In February 27, 2009 the IEEE standard 1900.4 for “Architectural Building Blocks Enabling Network-Device Distributed Decision Making for Optimized Radio Resource Usage in Heterogeneous Wireless Access Networks” was published [4]. All three types of CRS described above are included into this standard as use cases.

The scope of the IEEE standard 1900.4 is limited to architectural components of the intelligent management system. In particular, system and functional architectures as well as information model are defined. Detailed definition of service access points (SAP), interfaces, data models etc is left for the further stage. Correspondingly, IEEE 1900.4 WG is currently developing draft standard P1900.4.1 for “Interfaces and Protocols Enabling Distributed Decision Making for Optimized Radio Resource Usage in Heterogeneous Wireless Networks” [5].

In November 2008 FCC has published “Second Report and Order in the Matter of Unlicensed Operation in the TV

Broadcast Bands” allowing secondary operation in TV white space for portable devices [6]. This stimulated a lot of interest in developing standard for secondary mobile wireless access. As mentioned above, IEEE 802.22 WG is currently preparing P80.22a project authorization request.

Use case describing spectrum sharing type CRS is included into IEEE standard 1900.4. Correspondingly, the IEEE 1900.4 WG is currently developing draft standard P1900.4a for “Architecture and interfaces for dynamic spectrum access networks in white space frequency bands” [7].

This paper gives technical overview of IEEE standard 1900.4. Also, it explains scope and current status of P1900.4.1 and P1900.4a draft standards.

II. IEEE STANDARD 1900.4

The key elements of IEEE standard 1900.4 are system architecture, functional architecture, and information model.

A. IEEE 1900.4 System Architecture

The system architecture defined in the IEEE standard 1900.4 is shown in Figure 3. It defines management entities and interfaces comprising the intelligent management system to be deployed on top of a heterogeneous wireless environment.

TRC

TRM

TMC

RAN1

RANN

RMC RRC

OSM

NRM

Terminal Packet based core

network

TRC – Terminal Reconfiguration Controller TRM – Terminal Reconfiguration Manager TMC – Terminal Measurement Collector RMC – RAN Measurement Collector RRC – RAN Reconfiguration Controller OSM – Operator Spectrum Manager NRM – Network Reconfiguration Manager RAN – radio access network

Figure 3. IEEE 1900.4 system architecture.

Four management entities are defined on the network side: the Operator Spectrum Manager (OSM), the RAN Measurement Collector (RMC), the Network Reconfiguration Manager (NRM) and the RAN Reconfiguration Controller (RRC).

Operator Spectrum Manager is the entity that enables operator to control dynamic spectrum assignment decisions to be made by NRM.

For this purpose, the standard defines spectrum assignment policies. These policies express regulatory framework, defining spectrum usage rules for the frequency bands available to this operator. Also, these policies express operator objectives in

radio resource usage optimization related to dynamic spectrum assignment. Spectrum assignment policies are sent from OSM to NRM.

RAN Measurement Collector is the entity that collects RAN context information and provides it to the NRM.

RAN context information, as defined in the standard, may include the following:

RAN radio resource optimization objectives

RAN radio capabilities

RAN measurements

RAN transport capabilities.

Network Reconfiguration Manager is the entity that manages CWNs and terminals for network-terminal distributed optimization of radio resource usage and improvement in QoS.

On network side, NRM makes RAN reconfiguration decisions and sends RAN reconfiguration requests to RRC. In other words, NRM directly decides on reconfiguration of RANs related to dynamic spectrum assignment and dynamic spectrum sharing.

For managing terminal reconfiguration by NRM, the standard defines radio resource selection policies. These policies are sent from NRM to TRMs under its management and create the framework within which, TRMs will make terminal reconfiguration decisions.

To ensure stable operation of CWNs, radio resource selection policies may include the maximum time interval for reconfiguration. The reconfiguration of a terminal must be performed within this time interval starting from the time when this terminal has received these policies.

RAN Reconfiguration Controller is the entity that controls reconfiguration of RANs based on requests from the NRM.

To support scalable operation, RMC, NRM, RRC may be implemented in a distributed manner.

Three management entities are defined on the terminal side: the Terminal Measurement Collector (TMC), the Terminal Reconfiguration Manager (TRM) and the Terminal Reconfiguration Controller (TRC). Each terminal has one TMC, one TRM, and one TRC.

Terminal Measurement Collector is the entity that collects terminal context information and provides it to TRM.

Terminal context information defined in the standard may include the following:

User preferences

Required QoS levels

Terminal capabilities

Terminal measurements

Terminal geo-location information.

Terminal Reconfiguration Manager is the entity that manages the terminal for network-terminal distributed optimization of radio resource usage and improvement of QoS. This optimization is performed within the framework defined by the NRM and expressed by radio resource selection policies, and in a manner consistent with user preferences.

Terminal Reconfiguration Controller is the entity that controls the reconfiguration of terminal based on requests from TRM.

Correspondingly, six interfaces specified in the IEEE standard 1900.4 are used as described in the following (see Figure 3).

The interface between NRM and TRM is used to transmit the following:

From NRM to TRM:

o Radio resource selection policies

o RAN context information

o Terminal context information related to other terminals

From TRM to NRM:

o Terminal context information related to terminal of this TRM.

Two options are considered for the physical implementation of this interface. One option, termed out-band signaling, is to use a dedicated RAN. The other option, termed in-band signaling, is to use RANs having active connections with terminals. The standard supports both options including also a combined variant.

The interface between TRM and TRC is used to transmit the following:

From TRM to TRC:

o Terminal reconfiguration requests

From TRC to TRM:

o Terminal reconfiguration responses.

Interface between TRM and TMC is used to transmit the following:

From TRM to TMC:

o Terminal context information requests

From TMC to TRM:

o Terminal context information.

TRC and TMC provide media-independent standard interfaces for TRM to request terminal reconfiguration and to obtain terminal context information. This ensures that IEEE 1900.4 systems can operate with terminals supporting various radio interface technologies.

The interface between NRM and RRC is used to transmit the following:

From NRM to RRC:

o RAN reconfiguration requests

From RRC to NRM:

o RAN reconfiguration responses.

The interface between NRM and RMC is used to transmit the following:

From NRM to RMC:

o RAN context information requests

From RMC to NRM:

o RAN context information.

RRC and RMC provide media-independent standard interfaces for NRM to request RAN reconfiguration and to obtain RAN context information. This enables IEEE 1900.4 systems to support reconfiguration of various access points and base stations and to obtain context information from RANs using different radio interfaces.

The interface between NRM and OSM is used to transmit the following:

From OSM to NRM:

o Spectrum assignment policies

From NRM to OSM:

o Information on spectrum assignment decisions.

This interface defined in the standard provides the operator with reasonable control over NRM operation.

B. IEEE 1900.4 Functional Architecture

Functional architecture defined in the IEEE standard 1900.4 is shown in Figure 4. Functionality of OSM, RMC, RRC, TMC, and TRC entities is well defined in the system architecture. NRM and TRM are decision making entities. So, IEEE 1900.4 functional description concentrates on the functions inside NRM and TRM.

Six functions defined inside NRM are Policy Derivation, Policy Efficiency Evaluation, Network Reconfiguration Decision and Control, Spectrum Assignment Evaluation, Information Extraction, Collection, and Storage, and RAN Selection functions.

Policy Derivation function generates radio resource selection policies which guide TRMs in terminals reconfiguration decisions. The radio resource selection policies are derived using the context information from Information Extraction, Collection and Storage function. Policy Efficiency Evaluation function evaluates the efficiency of current radio resource selection policies. Evaluation results are used by Policy Derivation function during generating radio resource selection policies.

Network Reconfiguration Decision and Control function makes decisions on RANs reconfiguration compliant with spectrum assignment policies received from OSM. After making these decisions, this function sends corresponding reconfiguration commands to RRC. Also, this function sends information on made decisions to OSM. Spectrum

RAN

Packet based core network

NRM Network Reconfiguration

Decision and Control

Policy Derivation

Policy Efficiency Evaluation

Spectrum Assignment Evaluation

Information Extraction, Collection, and Storage

OSM

Terminal

TRM Terminal

Reconfiguration Decision and

Control

Information Extraction,

Collection, and Storage

TRC

TMC

RRC

RMC

RAN Selection

RAN Selection

- 1900.4 entities - functions related to decision making and reconfiguration - functions related to context awareness

- external interfaces of NRM and TRM functions related to decision making and reconfiguration

- external interfaces of NRM and TRM functions related to context awareness

- internal interfaces of NRM and TRM functions related to decision making and given as implementation example

- internal interfaces of NRM and TRM functions related to context awareness and given as implementation example

- internal interfaces of NRM and TRM functions related to sending radio resource selection policies and given as implementation example

- internal interfaces of NRM and TRM functions related to exchange of context information and given as implementation example

Figure 4. IEEE 1900.4 functional architecture.

Assignment Evaluation function evaluates the efficiency of spectrum usage under the current spectrum assignment. Evaluation results are used by Network Reconfiguration Decision and Control function during making decisions on RANs reconfiguration.

NRM Information Extraction, Collection and Storage function receives, processes, and stores RAN context information and terminal context information. RAN context information may include RAN radio resource optimization objectives, RAN radio and transport capabilities, and RAN measurements. RAN context information is received from RMC. Terminal context information may include user preferences, required QoS level, terminal capabilities, and terminal measurements. Terminal context information is received from TRM. NRM Information Extraction, Collection and Storage function provides information to functions inside NRM. It forwards RAN context information to TRM and may forward terminal context information, related to other terminals, to TRM.

NRM RAN Selection function selects RANs for exchanging radio resource selection policies and context information between NRM and TRM. This is done to minimize signaling overhead and to ensure timely and reliable delivery of radio resource selection policies and context information.

IEEE draft standard P1900.4 defines three functions inside TRM, that is, Terminal Reconfiguration Decision and Control, Information Extraction, Collection, and Storage, and RAN Selection functions.

Terminal Reconfiguration Decision and Control function makes decisions on terminal reconfiguration. These decisions are made within the framework determined by the radio resource selection policies received from NRM. After making these decisions, this function sends corresponding reconfiguration commands to TRC.

TRM Information Extraction, Collection and Storage function receives, processes, and stores terminal context information and RAN context information. Terminal context information is received from TMC. Terminal context information regarding other terminals may be received from NRM. RAN context information is received from NRM. TRM Information Extraction, Collection and Storage function provides information to functions inside TRM. Also, it forwards terminal context information to NRM.

TRM RAN Selection function selects RANs for exchanging radio resource selection policies and context information between NRM and TRM.

C. IEEE 1900.4 Information Model

IEEE standard 1900.4 uses an information model based on an object-oriented approach, where terminals and Composite Wireless Network (CWN) are viewed as managed objects. Three key groups of classes defined in the standard are policy, terminal, and CWN classes.

Policy classes are used to abstract spectrum assignment policies and radio resource selection policies. These classes are

Terminal

User

UserProfile

Application

UserSubscription

UserPreference

ApplicationProfile

ApplicationCapabilitites

ApplicationMeasurements

Device

DeviceProfile

DeviceCapabilitites

DeviceConfiguration

Link

LinkProfile

LinkCapabilitites

LinkMeasurements

DeviceMeasurements

ObservedChannel

ObservedChannelProfile

ObservedChannelCapabilitites

ObservedChannelMeasurements

RRSPolicy

Figure 5. Terminal classes.

used to describe policies of type Event-Condition-Action. Correspondingly, an event that triggers the evaluation of the policy condition, a condition that shall be fulfilled before applying the policy action, and the action that has to be performed if the event has occurred and the condition is fulfilled are described in these classes.

Terminal classes abstract the user, application, device, and radio resource selection policy concepts. They are summarized in Figure 5.

User class describes information related to a user of the terminal. User Profile contains general information about one user of terminal, for example, user ID. User Subscription class contains information about one subscription of the user. It describes which RANs and services the user has been subscribed in and what is the associated cost. User Preference class describes in a formalized form one preference of the user, for example, preferred operator and radio interface, perceived audio, image, or video quality, maximum cost, minimum data rate, etc.

Application class describes one currently active application. Application Profile class contains general information about the application, for example, application ID, traffic class, direction (downlink or uplink), links used to deliver this application, QoS requirements etc. Application Capabilities class contains information about measurements supported by this application, for example, delay, loss, and bandwidth measurements. Application Measurements class contains measurements performed by this application, such as delay, loss, and bandwidth measurements.

Device class describes all radio interface related hardware and software of a terminal, as well as, measurement information related to radio resources within the terminal. Device Profile class contains general information about the terminal, for example, terminal ID. Device Capabilities class contains information about terminal capabilities including both transmission and measurement capabilities, for example, supported radio interfaces, maximum transmission power, etc.

Device Configuration class contains information about the current configuration of terminal. Link class contains information about one active connection between terminal and RANs. Link Profile class contains general information about this active connection, for example, link ID, serving cell ID, channel used, etc. Link Capabilities class contains information about measurements supported on this active connection, such as block error rate, power, and signal-to-interference-plus-noise-ratio measurements. Link Measurements class contains current measurements related to this active connection, such as block error rate, power, and signal-to-interference-plus-noise-ratio measurements. Device Measurements class contains current measurements related to terminal, for example, battery capacity and terminal location measurements, as well as, measurements related to observed channels not having active connections with the terminal. Observed Channel class describes one frequency channel that does not have active connection with the terminal, but is observed by this terminal. Observed Channel Profile class contains general information about this frequency channel, for example, channel ID, frequency range, etc. Observed Channel Capabilities class contains information about measurements supported on this frequency channel, such as interference and load measurements. Observed Channel Measurements class contains current measurements related to this frequency channel, such as interference and load measurements.

RRS Policy class describes one radio resource selection (RRS) policy related to this terminal.

CWN classes abstract the operator and RAN concepts. They are summarized in Figure 6.

Operator class describes operator of this CWN. Operator Profile class contains general information about the operator, for example, operator ID. Operator Capabilities class describes operator capabilities. Assigned Channel class describes one frequency channel assigned to this operator. Assigned Channel Profile class contains general information about this frequency channel, for example, frequency channel ID, frequency range,

CWN

Operator

OperatorProfile

OperatorCapabilities

AssignedChannel

AssignedChannelProfile

RegulatoryRule

SAPolicy

RAN

RANProfile

RANConfiguration

BaseStation

BaseStationProfile

BaseStationCapabilities

BaseStationConfiguration

BaseStationMeasurements

Cell

CellProfile

CellCapabilities

CellConfiguration

CellMeasurements

Figure 6. CWN classes.

and allowed radio interfaces. Regulatory Rule class describes in a formalized form one regulatory rule to be applied to one or several assigned channels. SA Policy class describes one spectrum assignment (SA) policy specified by this operator.

RAN class describes one RAN of this CWN. RAN Profile class contains general information about this RAN, for example, RAN ID. RAN Configuration class describes current configuration of this RAN, for example, RAN users. Base Station class describes one base station of the RAN. Base Station Profile class contains general information about this base station, for example, base station ID, vendor, and location. Base Station Capabilities class contains information about base station capabilities including both transmission and measurement capabilities, for example, supported radio interfaces, supported channels, transport capability, etc. Base Station Configuration class contains information about the current configuration of the base station, for example, frequency channels and radio interfaces used. Base Station Measurements class contains current measurements performed by this base station, for example, transmission power and load measurements. Cell class describes one cell of the base station. Cell Profile class contains general information about this cell, for example, cell ID, location, coverage area, etc. Cell Capabilities class contains information about cell capabilities, for example, supported radio interfaces, supported channels, supported measurements, etc. Cell Configuration class contains information about the current configuration of the cell, for example, terminals served and transport service used. Cell Measurements class contains current measurements related to this cell, for example, transmission power, cell and traffic loads, throughput, and interference measurements.

IEEE 1900.4 information model is developed in an extensible form in order to accommodate future radio access technologies and allow for custom extensions to existing data models.

III. DRAFT STANDARD P1900.4.1

Development of the draft standard P1900.4.1 for “Interfaces and Protocols Enabling Distributed Decision Making for Optimized Radio Resource Usage in Heterogeneous Wireless Networks” started in March 2009.

P1900.4.1 uses the IEEE standard 1900.4 as a baseline standard. It provides detailed description of interfaces and service access points defined in the IEEE standard 1900.4 enabling distributed decision making in heterogeneous wireless

networks and obtaining context information for this decision making.

IEEE standard 1900.4 defines six interfaces between IEEE 1900.4 entities. P1900.4.1 will not define two out of these six interfaces – interface between the TRM and the TMC and interface between the TRM and the TRC – because it is currently assumed in the Working Group 1900.4 that most probably the TRM, the TMC, and the TRC will be produced by the same manufacturer. Also, P1900.4.1 currently plans to define two more interfaces: interface between several NRMs and interface between several TRMs. The interface between several NRMs can be used for the NRM collaboration when these NRMs are operated by different operators. The interface between several TRMs can be used for the TRM collaboration in case of terminal-to-terminal communication, for example, in relay mode. Interfaces to be defined in P1900.4.1 are summarized in Figure 7.

OSM

NRM

TRM

TMC

TRC

RRC

RMC

Terminal RAN Packet-based network

To otherTRM

To otherNRM

IEEE 1900.4 entity

IEEE 1900.4 rCFG_MEDIA_SAP to be further specified in P1900.4.1

IEEE 1900.4 interface to be further specified in P1900.4.1

IEEE 1900.4 interface not to be specified in P1900.4.1

Figure 7. P1900.4.1 interfaces and service access points.

In addition to interfaces, Figure 7 shows rCFG_MEDIA_SAP, which is media-dependent service access point. In general, this service access point provides reconfiguration and measurement services for managing RANs and terminals.

In P1900.4.1 it is planned to define rCFG_MEDIA_SAP for TMC and RMC entities to collect terminal context

information and RAN context information. Also, it is planned to define rCFG_MEDIA_SAP for TRC and RRC entities to control reconfiguration of terminals and RANs. Finally, it is planned to define rCFG_MEDIA_SAP for OSM entity to obtain regulatory information and operator requests regarding radio resource optimization in electronic format.

IV. DRAFT STANDARD P1900.4A

Development of the draft standard P1900.4a for “Architecture and interfaces for dynamic spectrum access networks in white space frequency bands” started in March 2009 together with P1900.4.1.

P1900.4a amends the IEEE standard 1900.4 to enable mobile wireless access service in white space frequency bands without any limitation on used radio interface (physical and media access control layers, carrier frequency, etc) by defining additional components of the IEEE 1900.4 system.

Currently considered architecture of P1900.4a is shown in Figure 8. Compared to IEEE standard 1900.4, four new entities are currently considered in P1900.4a: the Cognitive Base Station (CBS) Measurement Collector (CBSMC), the CBS Reconfiguration Manager (CBSRM), the CBS Reconfiguration Controller (CBSRC), and the White Space Manager (WSM).

WS RAN

RANN

TRC

TRM

TMC

RAN1 RMC

RRC

OSM

NRM

Terminal

Packet based network

CBSRC

CBSRM

CBSMC

CBS

WSM

TRC

TRM

TMC

Terminal

Another TRM

RAN – radio access network WS RAN – white space RAN CBS – Cognitive Base Station OSM – Operator Spectrum Manager NRM – Network Reconfiguration Manager TRM – Terminal Reconfiguration Manager CBSRM – CBS Reconfiguration Manager

RMC – RAN Measurement Collector TMC – Terminal Measurement Collector CBSMC – CBS Measurement Collector RRC – RAN Reconfiguration Controller TRC – Terminal Reconfiguration ControllerCBSRC – CBS Reconfiguration Controller WSM – White Space Manager

Another CBSRM

Another NRM

IEEE 1900.4 system

P1900.4a system

Radio enabler

Figure 8. P1900.4a architecture.

The CBS Measurement Collector is the entity that collects CBS context information and provides it to the CBSRM. Each CBS has one CBSMC.

The CBS Reconfiguration Manager is the entity that manages CBS and terminals for network-terminal distributed optimization of spectrum usage. Each CBS has one CBSRM.

The CBS Reconfiguration Controller is the entity that controls reconfiguration of CBS based on requests from the CBSRM. Each CBS has one CBSRC.

The White Space Manager can be considered as a substitution of the OSM and the NRM in P1900.4a. This entity enables collaboration between P1900.4a system and IEEE 1900.4 system, provides regulatory context information to the CBSRM, and enables communication between the CBSRM and white space database.

V. CONCLUSIONS

CRS can be defined as a radio system using technology that allows it to obtain knowledge of its operational environment, established policies and its internal state; dynamically and autonomously adjust its operational parameters and protocols according to the obtained knowledge and predefined objectives; and to learn from the results obtained.

Given such general definition many use cases and business cases are possible, including heterogeneous type CRS, spectrum sharing type CRS, and dynamic spectrum assignment type CRS. As a result, several standardization activities have been performed recently to enable such use cases and exploit the corresponding business opportunities.

This paper has given overview of standardization activities performing within the IEEE 1900.4 WG. Technical overview of IEEE standard 1900.4 has been presented concentrating on the key elements of the standard: system architecture, functional architecture, and information model.

IEEE standard 1900.4 was published in February 2009. Currently IEEE 1900.4 WG is developing two draft standards: P1900.4.1 for “Interfaces and Protocols Enabling Distributed Decision Making for Optimized Radio Resource Usage in Heterogeneous Wireless Networks” and P1900.4a for “Architecture and interfaces for dynamic spectrum access networks in white space frequency bands.” The paper has presented some insights on the scope and current status of these two draft standards.

REFERENCES [1] ITU-R WP 1B Liaison statement to WP 5A, “On the study of software-

defined radio and cognitive radio systems,” Mar. 20, 2009.

[2] IEEE Standard 802.21 for Local and metropolitan area networks – Part 21: Media Independent Handover Services, Jan. 21, 2009.

[3] http://www.ieee802.org/22/

[4] IEEE Standard 1900.4 for Architectural Building Blocks Enabling Network-Device Distributed Decision Making for Optimized Radio Resource Usage in Heterogeneous Wireless Access Networks, Feb. 27, 2009.

[5] IEEE P1900.4.1 PAR, “Interfaces and protocols enabling distributed decision making for optimized radio resource usage in heterogeneous wireless networks,” Mar. 19, 2009.

[6] FCC 08-260, “Second Report and Order in the Matter of Unlicensed Operation in the TV Broadcast Bands,” Nov. 14, 2008.

[7] IEEE P1900.4a PAR, “Architecture and interfaces for dynamic spectrum access networks in white space frequency bands,” Mar. 19, 2009.