3 DECT

 DECT, or Digital Enhanced Cordless Telecommunications, is a fully digital cellular network system designed to replace older analog cordless phone systems like CT1 and CT1+

1. Purpose and Scope:

   • DECT is designed for use in various environments such as offices, campuses, trade shows, and homes.
   • It can also be used to establish access points to the PSTN (Public Switched Telephone Network) in locations like railway stations, government buildings, and hospitals.
   • DECT can bridge the gap between network operators and customers, offering local loop services without extensive infrastructure installation.

2. Interworking Capabilities:

   • DECT systems can interwork with GSM, ISDN, and data networks, facilitating seamless connectivity and integration with existing telecommunications infrastructure.
   • Over 100 million DECT units are currently in use, highlighting its widespread adoption and versatility.

3. Cell Diameter and Capacity:

   • Unlike GSM, which is designed for outdoor use with larger cell diameters (up to 70 km), DECT has a limited range of about 300 meters from the base station (around 50 meters indoors).
   • Despite its limited range, DECT can accommodate up to 10,000 users within one square kilometer, making it suitable for densely populated urban areas.

4. Base Station Cost and Deployment:

   • DECT base stations, along with mobile stations, are more affordable (in the range of €100) compared to GSM base stations (several €10,000).
   • DECT base stations can be used by individuals for private networks, unlike GSM base stations, which require licensing and are typically operated by network operators.

5. Frequency and Channel Allocation:

   • DECT operates in the frequency range of 1880–1990 MHz, offering 120 full duplex channels.
   • It utilizes Time Division Duplexing (TDD) with 10 ms frames, subdividing the frequency range into 10 carrier frequencies using Frequency Division Multiple Access (FDMA) and dividing each frame into 24 slots using Time Division Multiple Access (TDMA).
   • The digital modulation scheme used in DECT is Gaussian Minimum Shift Keying (GMSK), with each station having an average transmission power of 10 mW (maximum 250 mW).

In summary, DECT provides a cost-effective and versatile solution for wireless telecommunication in various settings, offering interworking capabilities, efficient channel allocation, and widespread adoption. Its characteristics make it suitable for indoor and short-range outdoor applications, enabling reliable voice and data communication for both individual and commercial use.

DECT (Digital Enhanced Cordless Telecommunications) systems offer several features that make them suitable for various telecommunication applications. Here are some key features of DECT systems:

1. Wide Coverage Range: DECT systems provide reliable wireless communication over a wide coverage area, typically up to 300 meters outdoors and around 50 meters indoors from the base station.

2. High Capacity: Despite their limited coverage range, DECT systems can support a large number of users within their coverage area, making them suitable for crowded environments like offices, campuses, and trade shows.

3. Voice and Data Support: DECT systems support both voice and data transmission, enabling users to make phone calls and transmit data wirelessly.

4. Interference-Free Communication: DECT operates in a frequency range of 1880-1990 MHz, which is separate from the frequencies used by other wireless communication technologies like Wi-Fi and Bluetooth. This separation reduces interference and ensures reliable communication.

5. Security: DECT systems incorporate encryption and authentication mechanisms to ensure the security of voice and data transmissions, protecting against eavesdropping and unauthorized access.

6. Mobility and Handover: DECT supports seamless handover between base stations as users move within the coverage area. This mobility feature allows users to maintain ongoing calls without interruption while moving from one location to another.

7. Scalability: DECT systems can be easily expanded by adding additional base stations to extend coverage or accommodate more users, making them highly scalable to meet changing communication needs.

8. Integration with Other Networks: DECT systems can integrate with various telecommunication networks, including PSTN (Public Switched Telephone Network), ISDN (Integrated Services Digital Network), GSM (Global System for Mobile Communications), and IP networks, enabling interoperability and seamless communication between different networks.

9. Support for Additional Services: DECT systems support additional telecommunication services such as call forwarding, call waiting, caller ID, conference calling, and voice messaging, enhancing user productivity and convenience.

10. Low Power Consumption: DECT handsets are designed to operate efficiently on battery power, resulting in extended battery life and prolonged usage between charges.

architecture

In the DECT system architecture, various physical implementations can exist depending on the specific use case. However, they are all based on the same logical reference model, as depicted in Figure 4.18. Here's an overview of the key components and their roles within the DECT system architecture:

1. Global Network (GN):

   • Connects the local communication structure to external networks such as ISDN, PSTN, PLMN (e.g., GSM), or PSPDN.
   • Offers services through interface D1, including data transportation, address translation, and routing between local and global networks.

2. Local Networks:

   • Provide local telecommunication services, ranging from basic switching to advanced features like intelligent call forwarding and address translation.
   • Examples include analog or digital Private Branch Exchanges (PBXs) and Local Area Networks (LANs) following IEEE 802.x standards.
   • Typical network functions are integrated into local or global networks, where databases like Home Data Base (HDB) and Visitor Data Base (VDB) are located.
   • HDB and VDB support mobility functions similar to those in HLR (Home Location Register) and VLR (Visitor Location Register) in GSM systems.

3. DECT Core Network:

   • Consists of Fixed Radio Termination (FT) and Portable Radio Termination (PT), providing multiplexing services.
   • FT covers layers one to three on the fixed network side, while PT covers layers one to three on the mobile network side.
   • Several Portable Applications (PA) can be implemented on devices within the DECT core network.

Overall, the DECT system architecture facilitates communication between local and global networks, supporting various telecommunication services while ensuring mobility and seamless integration with external networks. The core network components, FT and PT, play crucial roles in managing communication and providing multiplexing services within the DECT system.

The DECT protocol reference architecture aligns with the OSI reference model, that facilitate communication within the DECT system. Here's an overview of each layer:

1. Physical Layer:

   • Handles modulation/demodulation, signal detection, synchronization, and status information collection.
   • Generates the physical channel structure with guaranteed throughput.
   • Assigns channels for data transmission upon request from the MAC layer.
   • Utilizes a TDMA frame structure with 12 slots for both downlink and uplink in the basic connection mode.
   • Each slot contains a synchronization pattern followed by data fields for network control, user data, and transmission quality.

2. Medium Access Control (MAC) Layer:

   • Establishes, maintains, and releases channels for higher layers by activating and deactivating physical channels.
   • Multiplexes several logical channels onto physical channels.
   • Manages logical channels for signaling, network control, user data transmission, paging, and broadcast messages.
   • Provides services for segmentation/reassembly of packets and error control/correction.

3. Data Link Control (DLC) Layer:

   • Creates and maintains reliable connections between the mobile terminal and the base station.
   • Defines services for both the Control Plane (C-Plane) and User Plane (U-Plane).
   • C-Plane services include a connectionless broadcast service for paging and a point-to-point protocol similar to LAPD in ISDN (LAPC+Lc).
   • U-Plane services include various types of services such as transparent unprotected service, forward error correction service, rate adaptation services, and services for future enhancements.

4. Network Layer:

   • Exists only for the C-Plane and is similar to those in ISDN and GSM.
   • Provides services for requesting, checking, reserving, controlling, and releasing resources at fixed stations and mobile terminals.
   • Handles mobility management responsible for identity management, authentication, and management of location databases.
   • Manages call control for connection setup, release, and negotiation.
   • Supports two message services: connection-oriented message service (COMS) and connectionless message service (CLMS) for data transfer to and from the interworking unit connecting the DECT system with external networks.

Overall, the DECT protocol reference architecture encompasses layers for physical transmission, channel management, reliable connection establishment, and network resource management, ensuring efficient communication within DECT systems.

TETRA (Terrestrial Trunked Radio) is a digital radio communication standard primarily used for professional mobile radio (PMR) and public safety communication systems. It provides a secure and reliable means of communication for organizations such as emergency services, transportation agencies, utilities, and other industries requiring robust and efficient radio communication.

Here are some key features and aspects of TETRA:

1. Digital Communication: TETRA employs digital modulation techniques for voice and data transmission, offering improved audio quality, clarity, and reliability compared to traditional analog systems. It utilizes Time Division Multiple Access (TDMA) technology to divide radio channels into time slots, allowing multiple users to share the same frequency channel efficiently.

2. Secure Communication: Security is a critical aspect of TETRA systems, with built-in encryption algorithms to protect sensitive communications from interception and unauthorized access. TETRA supports end-to-end encryption of voice and data transmissions, ensuring confidentiality and integrity of information.

3. Efficient Spectrum Usage: TETRA optimizes spectrum utilization through TDMA, enabling multiple users to communicate simultaneously on the same frequency channel without interference. This efficient use of spectrum resources maximizes the capacity of the communication system, allowing for more users and channels within a limited frequency bandwidth.

4. Reliable Coverage: TETRA systems are designed to provide reliable coverage in various environments, including urban, suburban, and rural areas, as well as indoor and underground locations. Repeaters and infrastructure components are strategically deployed to ensure seamless communication coverage across the operational area.

5. Group Communication: TETRA supports group communication features, allowing users to communicate within predefined talk groups or channels. This facilitates coordinated operations and collaboration among team members, essential for emergency response and public safety organizations.

6. Priority and Preemption: TETRA systems offer priority access for critical communications, ensuring that emergency calls and high-priority users receive immediate attention and channel allocation, even during periods of network congestion. Preemption features allow authorized users to override ongoing calls to transmit urgent messages when necessary.

7. Data Services: In addition to voice communication, TETRA supports various data services such as short data messaging (SDM), packet data services, status messaging, and location-based services. These data capabilities enhance operational efficiency and enable applications like fleet management, telemetry, and remote control.

8. Interoperability: TETRA systems are designed to be interoperable with legacy analog radio systems as well as other digital communication standards, allowing seamless integration with existing infrastructure and equipment. This interoperability ensures smooth transition and compatibility with diverse communication networks and devices.

9. Network Management: TETRA networks are managed through centralized network management systems (NMS), which provide monitoring, configuration, and maintenance capabilities for network operators. NMS tools enable administrators to optimize network performance, troubleshoot issues, and ensure service reliability.

10. International Standardization: TETRA is an internationally recognized standard governed by standards bodies such as the European Telecommunications Standards Institute (ETSI) and the Telecommunications Industry Association (TIA). Its standardized specifications ensure compatibility and interoperability among TETRA-compliant equipment and systems worldwide.

Overall, TETRA is a versatile and robust communication solution tailored to the needs of mission-critical users, offering secure, reliable, and efficient voice and data communication capabilities essential for public safety, emergency response, and industrial operations.

UMTS (Universal Mobile Telecommunications System) is a third-generation (3G) mobile communication technology that is part of the International Mobile Telecommunications-2000 (IMT-2000) family of standards. IMT-2000 is a global standard framework established by the International Telecommunication Union (ITU) for mobile telecommunications systems that provide a wide range of services, including voice, data, and multimedia, over wireless networks.

Here's an overview of UMTS and its relationship to IMT-2000:

1. UMTS (Universal Mobile Telecommunications System):

   • UMTS is a 3G wireless communication technology developed to succeed second-generation (2G) mobile systems like GSM (Global System for Mobile Communications).
   • It provides higher data speeds, enhanced multimedia capabilities, and better spectrum efficiency compared to 2G systems.
   • UMTS supports various services, including voice calls, high-speed data transmission, video streaming, mobile internet access, and multimedia messaging.
   • The UMTS standard is based on the Wideband Code Division Multiple Access (WCDMA) air interface, which uses CDMA technology for multiple users to share the same frequency spectrum efficiently.

2. IMT-2000 (International Mobile Telecommunications-2000):

   • IMT-2000 is a global standard framework developed by the ITU to define requirements for 3G mobile communication systems.
   • It aims to ensure interoperability and compatibility among different 3G systems deployed worldwide, allowing users to roam seamlessly across networks and access services internationally.
   • IMT-2000 standards encompass a range of technologies and air interfaces, including UMTS (WCDMA), CDMA2000, and TD-SCDMA (Time Division-Synchronous Code Division Multiple Access).
   • The primary goals of IMT-2000 are to provide high-speed data transmission, multimedia support, global roaming, and improved quality of service (QoS) for mobile communication services.

3. Relationship between UMTS and IMT-2000:

   • UMTS is one of the air interface technologies specified under the IMT-2000 standard.
   • It represents the European and international implementation of IMT-2000, adhering to the technical requirements and performance criteria set forth by the ITU.
   • Other technologies like CDMA2000 and TD-SCDMA also fall under the IMT-2000 umbrella, offering alternative approaches to achieving 3G mobile communication objectives.
   • UMTS networks deployed worldwide conform to the IMT-2000 standards, ensuring compatibility and interoperability with other IMT-2000-compliant systems.

In summary, UMTS is a 3G mobile communication technology that operates within the IMT-2000 standard framework established by the ITU. It provides high-speed data, multimedia, and voice services, while IMT-2000 defines the global requirements and specifications for 3G mobile systems to ensure interoperability and compatibility across networks worldwide.

The UMTS reference architecture consists of several components and domains to facilitate the provision of mobile communication services. Here's an overview of the simplified UMTS reference architecture:

1. UTRAN (UMTS Terrestrial Radio Access Network):

   • UTRAN handles cell-level mobility and includes multiple Radio Network Subsystems (RNS).
   • Functions of RNS include radio channel ciphering and deciphering, handover control, and radio resource management.
   • UTRAN communicates with User Equipment (UE) via the Uu radio interface, which is comparable to the Um interface in GSM.
   • Via the Iu interface, which is similar to the A interface in GSM, UTRAN connects to the Core Network (CN).

2. Core Network (CN):

   • The CN contains functions for inter-system handover, gateways to other networks (fixed or wireless), and performs location management.
   • It is connected to UTRAN via the Iu interface.
   • The CN further subdivides into domains, each serving specific functions:

   a. User Equipment Domain:

   • Assigned to a single user and comprises functions needed to access UMTS services.
   • Includes the USIM domain and the mobile equipment domain.

   b. USIM (UMTS Subscriber Identity Module) Domain:

   • Contains the USIM, which performs encryption, authentication, and stores user-related data for UMTS.

   c. Mobile Equipment Domain:

   • Contains the end device itself, where all functions for radio transmission and user interfaces are located.

   d. Infrastructure Domain:

   • Shared among all users and offers UMTS services to accepted users.
   • Includes the access network domain and the core network domain.

   e. Access Network Domain:

   • Contains the radio access networks (RAN), responsible for connecting UE to UTRAN.

   f. Core Network Domain:

• Contains access network-independent functions.

• Further divided into three domains:

  • Serving Network Domain: Functions used by a user for accessing UMTS services.
  • Home Network Domain: Functions related to the home network of a user, such as user data look-up.
  • Transit Network Domain: Necessary if the serving network cannot directly contact the home network.

• These domains describe functionalities and may be part of the same physical network.