The uplink frequency range specified for GSM is 933 - 960 MHz (basic 900 MHz band only). The downlink frequency band 890 - 915 MHz (basic 900 MHz band only).
SD blocking means that you are not getting SD resource for the call origination. When MS connects with NW then RACH and AGCH are provided. After AGCH,SDCCH is provided but if SDCCH is not provided at this time due some problems or due to unavailable of SD by BSC ,it's called as SD Blocking.
• There are four basic types of handoffs in GSM network:
- Intra-cell handover. Such a kind of handover is performed to optimize the traffic load in the cell or to improve quality of a connection by changing carrier frequency.
- 2 Inter-cell handover.
- 3 Inter-BSC handover.
- 4 Inter-MSC handover.
TCH Blocking: Reason & Solution. For Ericsson Vendor. When TCH is not allocated to the user after SD allocation ,it is TCH Blocking. It is the failed call attempts which the MS user can notice. It takes place due to lack of TCH Resource.
TCH Drop: Reason & Solution. Drop during conversation is known as TCH drop. It takes place after connect. ACK msg on TCH. TCH drop occurring.
Frame structure is the division of defined length of digital information into different fields (information parts). A GSM frame is 4.615 msec and it is composed of 8 time slots (numbered 0 through 7). During voice communication, one user is typically assigned to each time slot within a frame.
GSM supports full- rate calls and half-rate calls. A full-rate call uses one time slot in every frame, while a half-rate call uses one time slot in every two frames. Once an MS initiates a full-rate (half- rate) call request, the MS will operate in full-rate (half-rate) mode until the call is terminated.
GSM uses a variety of 'channels' in which the data is carried. In GSM, these channels are separated into physical channels and logical channels. The Physical channels are determined by the timeslot, whereas the logical channels are determined by the information carried within the physical channel.
The Base Station Identity Code (BSIC) is a code used in GSM to uniquely identify a base station. The code is needed because it is possible that mobile stations receive the broadcast channel of more than one base station on the same frequency. This is due to frequency re-use in a cellular network.
The Common Control Channel (CCCH) is responsible for transferring control information between all mobiles and the BTS. Random Access Channel (RACH) Used by the mobile when it requires gaining access to the system.
The GSM architecture consists of three major interconnected subsystems that interact with themselves and with users through certain network interface. The subsystems are Base Station Subsystem (BSS), Network Switching Subsystem (NSS) and Operational Support Subsystem (OSS).
GSM Logical Channels. Traffic Channels (TCH) A traffic channel (TCH) is used to carry speech and data traffic. Traffic channels are defined using a 26-frame multi frame, or group of 26 TDMA frames. The length of a 26-frame multi frame is 120ms.
The Absolute Radio Frequency Channel Number (ARFCN) is a unique number given to each radio channel in GSM. The ARFCN can be used to calculate the exact frequency of the radio channel. Within the GSM900 band ARFCN 1 to 124 are used. In the GSM1800 band ARFCN 512 to 885 are used.
Control channels are communication channels used in a system (such as a radio control channel), which are dedicated to the sending and/or receiving of command messages between devices (such as a base station and a mobile radio).
Logical Channel. A logical channel is defined by the type of information it carries and is generally classified as a control channel, used for transmission of control and configuration information necessary for operating an LTE system, or as a traffic channel, used for the user data.
voice channel - Computer Definition
A transmission channel or subchannel that has the bandwidth necessary to carry human voice. See voice grade. Computer Desktop Encyclopedia THIS DEFINITION IS FOR PERSONAL USE ONLY All other reproduction is strictly prohibited without permission from the publisher.GSM architecture is a layered model that is designed to allow communications between two different systems. The lower layers assure the services of the upper-layer protocols. Each layer passes suitable notifications to ensure the transmitted data has been formatted, transmitted, and received accurately.
GSM (Global System for Mobile communication) is a digital mobile network that is widely used by mobile phone users in Europe and other parts of the world. GSM digitizes and compresses data, then sends it down a channel with two other streams of user data, each in its own time slot.
The information flows between the different protocols layers are known as channels. These channels provide interfaces to each layers within the LTE protocol stack and enable an orderly and defined segregation of the data.
The slot is then the time that is allocated to the particular user, and the GSM burst is the transmission that is made in this time. Each GSM slot, and hence each GSM burst lasts for 0.577 mS (15/26 mS). Eight of these burst periods are grouped into what is known as a TDMA frame.
GSM network interfaces list. The Abis interface allows control of the radio equipment and radio frequency allocation in the BTS. A interface The A interface is used to provide communication between the BSS and the MSC.
In 2001, the first UMTS (W-CDMA) network was launched, a 3G technology that is not part of GSM. GSM is a second-generation (2G) standard employing time-division multiple-Access (TDMA) spectrum-sharing, issued by the European Telecommunications Standards Institute (ETSI).
Call flow describes the process by which a network routes a call to a mobile device. Even LTE devices still use 3G networks for most voice calls. 3G call flow is different in a GSM network than in a CDMA network.
A GSM Multiframe is the basic unit, and is 120 ms long. There are 26 Frames in each Multiframe, with each Frame being 4.61538 ms long (120 ms/26). Within each Frame are 8 Timeslots at 576.92 μs per Timeslot (577 μs in round numbers). Finally, there are 156.25 Bits per Timeslot, each Bit being 3.69231 μs long.
A communication channel is the medium, mean, manner or method through which a message is sent to its intended receiver. The basic channels are written (hard copy print or digital formats), oral or spoken, and electronic and multimedia. Different types of communication media have varying channel richness.
Paging • Paging is the one-to-one communication between the mobile and the base station • Paging is a procedure the network uses to find out a subscriber's location before actual call establishment. • Paging is used to alert the mobile station of an incoming call.
Paging is a generic term and it's also used in LTE, so I thought about writing a small but not detailed article on Paging, it's uses and how physical layer is involved in Paging process. Paging is mostly a RRC procedure and it simply means waking up the UE which is Idle, if there is some data for it.
A forward channel refers to the frequencies used by a telephone tower to communicate with all nearby cellular phones. Contrastingly, a reverse channel refers to the frequencies used by cellular telephones to communicate with a telephone tower.
paging system - Computer Definition. A public address, or loudspeaker, system used to make announcements and notify or summon people. In large buildings, paging systems commonly are divided into a number of zones, or coverage areas. If that pager were in range, it beeped, hence the term beeper.
Paging (Wireless Networks) Paging is a method of delivering a message, via a public or private communications system or radio signal, to a person whose exact whereabouts are unknown. Commercial paging service began in 1949 with the allocation of frequencies exclusively dedicated to one-way signaling services.
