|
Radio Link Control
Radio link control (RLC) is a layer 2 Radio Link Protocol used in UMTS, LTE and 5G on the Air interface. This protocol is specified by 3GPP in TS 25.322 for UMTS, TS 36.322 for LTE and TS 38.322 for 5G New Radio (NR). RLC is located on top of the 3GPP MAC-layer and below the PDCP Packet Data Convergence Protocol (PDCP) is specified by 3GPP in TS 25.323 for UMTS, TS 36.323 for LTE and TS 38.323 for 5G. PDCP is located in the Radio Protocol Stack in the UMTS/LTE/5G air interface on top of the RLC layer. PDCP provides its ...-layer. The main tasks of the RLC protocol are: * Transfer of upper layer Protocol Data Units (PDUs) in one of three modes: Acknowledged Mode (AM), Unacknowledged Mode (UM) and Transparent Mode (TM) * Error correction through ARQ (only for AM data transfer) * Concatenation, segmentation and reassembly of RLC SDUs (UM and AM) * Re-segmentation of RLC data PDUs (AM) * Reordering of RLC data PDUs (UM and AM); * Duplicate detection (UM and AM); * RLC SDU dis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Link Protocol
Radio Link Protocol (RLP) is an automatic repeat request ( ARQ) fragmentation protocol used over a wireless (typically cellular) air interface. Most wireless air interfaces are tuned to provide 1% packet loss, and most Vocoders are mutually tuned to sacrifice very little voice quality at 1% packet loss. However, 1% packet loss is intolerable to all variants of TCP, and so something must be done to improve reliability for voice networks carrying TCP/IP data. A RLP detects packet losses and performs retransmissions to bring packet loss down to .01%, or even .0001%, which is suitable for TCP/IP applications. RLP also implements stream fragmentation and reassembly, and sometimes, in-order delivery. Newer forms of RLP also provide framing and compression, while older forms of RLP rely upon a higher-layer PPP protocols to provide these functions. A RLP transport cannot ask the air interface to provide a certain payload size. Instead, the air interface scheduler determines the packet si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UMTS
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 (3rd Generation Partnership Project), UMTS is a component of the International Telecommunication 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. UMTS specifies a complete network system, which includes the radio access network ( UMTS Terrestrial Radio Access Network, or UTRAN), the core network (Mobile Application Part, or MAP) and the authentication of users via SIM ( subscriber identity module) cards. The technology described in UMTS is sometimes also referred to as Freedom of Mobile Multimedia Access (FOMA) or 3GSM. Unlike EDGE (IMT Single-Carrier, based o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LTE (telecommunication)
In telecommunications, long-term evolution (LTE) is a Technical standard, standard for wireless broadband communication for mobile devices and data terminals, based on the GSM/Enhanced Data Rates for GSM Evolution, EDGE and UMTS/High Speed Packet Access, HSPA standards. It improves on those standards' capacity and speed by using a different radio interface and core network improvements. LTE is the upgrade path for carriers with both GSM/UMTS networks and CDMA2000 networks. Because LTE frequency bands, LTE frequencies and bands differ from country to country, only multi-band phones can use LTE in all countries where it is supported. The standard is developed by the 3GPP (3rd Generation Partnership Project) and is specified in its Release 8 document series, with minor enhancements described in Release 9. LTE is also called 3.95G and has been marketed as "4G LTE" and "Advanced 4G"; but it does not meet the technical criteria of a 4G wireless service, as specified in the 3GPP Relea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Air Interface
The air interface, or access mode, is the communication link between the two stations in mobile or wireless communication. The air interface involves both the physical and data link layers (layer 1 and 2) of the OSI model for a connection. Physical Layer The physical connection of an air interface is generally radio-based. This is usually a point to point link between an active base station and a mobile station. Technologies like Opportunity-Driven Multiple Access (ODMA) may have flexibility regarding which devices serve in which roles. Some types of wireless connections possess the ability to broadcast or multicast. Multiple links can be created in limited spectrum through FDMA, TDMA, or SDMA. Some advanced forms of transmission multiplexing combine frequency- and time-division approaches like OFDM or CDMA. In cellular telephone communications, the air interface is the radio-frequency portion of the circuit between the cellular phone set or wireless modem (usually portable or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Media Access Control
In IEEE 802 LAN/MAN standards, the medium access control (MAC, also called media access control) 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. The LLC provides flow control and multiplexing for the logical link (i.e. EtherType, 802.1Q VLAN tag etc), while the MAC provides flow control and multiplexing for the transmission medium. These two sublayers together correspond to layer 2 of the OSI model. For compatibility reasons, LLC is optional for implementations of IEEE 802.3 (the frames are then "raw"), but compulsory for implementations of other IEEE 802 physical layer standards. Within the hierarchy of the OSI model and IEEE 802 standards, the MAC sublayer provides a control abstraction of the physical layer such that the complexities of physical link control are invisible to the LLC and upper ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PDCP
Packet Data Convergence Protocol (PDCP) is specified by 3GPP in TS 25.323 for UMTS, TS 36.323 for LTE and TS 38.323 for 5G. PDCP is located in the Radio Protocol Stack in the UMTS/LTE/5G air interface on top of the RLC layer. PDCP provides its services to the RRC and user plane upper layers, e.g. IP at the UE or to the relay at the base station. The following services are provided by PDCP to upper layers: * transfer of user plane data; * transfer of control plane data; * header compression; * ciphering; * integrity protection. The header compression technique can be based on either IP header compression (RFC 2507) or Robust Header Compression Robust Header Compression (ROHC) is a standardized method to compress the IP, UDP, UDP-Lite, RTP, and TCP headers of Internet packets. The need for header compression In streaming applications, the overhead of IP, UDP, and RTP is 40 bytes f ... (RFC 3095). If PDCP is configured for ''No Compression'' it will send the IP Packets ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Automatic Repeat Request
Automatic repeat request (ARQ), also known as automatic repeat query, is an error-control method for data transmission that uses acknowledgements (messages sent by the receiver indicating that it has correctly received a packet) and timeouts (specified periods of time allowed to elapse before an acknowledgment is to be received) to achieve reliable data transmission over an unreliable communication channel. If the sender does not receive an acknowledgment before the timeout, it re-transmits the packet until it receives an acknowledgment or exceeds a predefined number of retransmissions. Variations of ARQ protocols include Stop-and-wait ARQ, Go-Back-N ARQ, and Selective Repeat ARQ. All three protocols usually use some form of sliding window protocol to help the sender determine which (if any) packets need to be retransmitted. These protocols reside in the data link or transport layers (layers 2 and 4) of the OSI model. Examples The Transmission Control Protocol uses a varian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mobile Telecommunications Standards
Mobile may refer to: Places * Mobile, Alabama, a U.S. port city * Mobile County, Alabama * Mobile, Arizona, a small town near Phoenix, U.S. * Mobile, Newfoundland and Labrador Arts, entertainment, and media Music Groups and labels * Mobile (band), a Canadian rock band * Mobiles (band), a 1980s British band Other uses in music * ''Mobile'' (album), a 1999 album by Brazilian Paulinho Moska * "Mobile" (song), a 2003 song by Avril Lavigne from ''Let Go'' * "Mobile", a song by Gentle Giant from the album ''Free Hand'' Other uses in arts, entertainment, and media * Mobile (sculpture), a kinetic sculpture constructed to take advantage of the principle of equilibrium * ''Mobile'' (TV series), a British ITV drama * "Mobile", a short story by J. G. Ballard, later renamed "Venus Smiles" * Mobile, a feature of the game ''GunBound'' * ''Mobile Magazine'', a publication on portable electronics Military and law enforcement * '' Garde Mobile'', historic French military unit * Mobile ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
5G (telecommunication)
In telecommunications, 5G is the fifth-List of mobile phone generations, generation Technical standard, technology standard for broadband cellular networks, which mobile network operator, cellular phone companies began deploying worldwide in 2019, and is the planned successor to the 4G networks which provide connectivity to most current cellphones. 5G networks are predicted to have more than 1.7 billion subscribers and account for 25% of the worldwide mobile technology market by 2025, according to the GSMA, GSM Association and Statista. Like its predecessors, 5G networks are cellular networks, in which the service area is divided into small geographical areas called ''cells''. All 5G wireless devices in a cell are connected to the Internet and telephone network by radio waves through a local antenna (radio), antenna in the cell. The new networks have higher download speeds, eventually up to 10 gigabits per second (Gbit/s). In addition to 5G being faster than existing netwo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
