BSC

BASE STATION CONTROLLER

FUNCTION BSC

BSC controls the most important part of the radio network. The most important task is to ensure the best function of radio resources. The main function of the BSC are:

·         Radio Network Management

·         RBS Management

·         TRC Handling

·         Transmission Network Management

·         Internal BSC Operation and Maintenance

·         Handling of MS Connections

RADIO NETWORK MANAGEMENT

Radio Network Management including the tasks below:

·         Administration of Radio Data Network include:

•         Description of the data cell (eg, cell identity, BCCH channel number, minimum and maximum output power of the cell, the type of RBS, etc.)

•         System data information (eg information on whether a cell can not access, maximum and  minimum power output allowed in a cell, the BCCH channel identity within cell)

•         Data location (eg cell levels used in the HCS and situations where traffic is high) - Data that includes cell division, including the parameters to perform a quick handover of the crowded cell.

·         Traffic and measurement: (example: the number of calls, density, level of traffic for a HP, the number of handover, the number of failed relationships, etc.)

·         Measurement of free channels: RBS collects statistics from HP about the strength and signal quality. These statistics are used for channel allocation process, therefore the weak interference channel is allocated to the relationship.

RBS MANAGEMENT

Implementation of RBS Ericsson is the orientation of the recipient, additional security features that are nice. This means less likely to use multiple transceiver devices together.

This philosophy allows the main link between the BSC and the transceiver in the RBS. Logic model of RBS can be built in the BSC and the RBS can be limited, connected, and not connected.

The main task of the RBS management are:

·         RBS configuration: including allocation of frequencies for the combination of channel and power level for each cell according to the device inventory. If there is damage to the device as you lose an important channel, the device reconfiguration, and the expense of channels is less important.

·         Handling of RBS software: provides control of the load program.

·         Maintenance of the RBS: RBS of damaged and disturbed will be locked automatically.

HANDLING TRC

Although traumatic located in the TRC, BSC, as an inventory control radio resources in GSM networks, routinely coordinate the traumatic situation to call.

During the call set-up, BSC instructs the TRC to allocate equipment to call TRA. If one allows TRC to confirm the allocation of the TRA. And BSC TRA will control the device during the call lasted.

TRANSMISSION NETWORK MANAGEMENT

Transmission Network for the BSC, including the links to and from the MSC / VLR and RBS, including:

·         Transmission Interface Handling: provide administrative functions, supervision, testing and localization of damage from link RBS. BSC configuration, allocation and supervision of the link circuit 64 Kbps PCM into RBS. It also directly controls the remote switch in RBS which allows the use of 64 Kbps circuits efficiently.

OPERATION AND MAINTENANCE OF INTERNAL BSC

Operation and maintenance tasks can be done in the BSC alone or diremote of OSS. Operation and maintenance of internal BSC is as follows:

·         Maintenance of TRH: Administration, supervision and testing of TRH (Trasceiver Handler) implemented in the BSC. TRH consists of hardware and software. A TRH is located in the Regional Processor for Group switch (RPG). One RPG can serve several transciever. In a BSC could have some RPG.

·         Processor Load Control in the BSC: This function ensures long as processors get overloaded, some calls can still be handled by the BSC. If too many calls are received, real-time purposes such as time of set-ups can not be met. To prevent this, several calls have to be rejected in high load conditions. Calls recently received by the system provided full service and is not affected by overload conditions.

COPING WITH MS

Development relations

     Included in the call set-up is the process as follows:

·         Paging: BSC sends the paging message to the RBS-RBS which is limited in scope LA. Load conditions in the BSC inspected prior to the paging command is sent to the RBS.

·         Signalling Set-Up: During the call set-up, MS relationship is transferred to a SDCCH is allocated by a BSC. If MS started building relationships, BSC check processor load before the relationship further processing.

·         assignment of Traffic Channel: After SDCCH divide tasks, call set-up procedure followed by a division of TCH and BSC. During the process, the radio channel control functions in the BSC was informed that the MS has been ordered to change the channel. If all the TCH in a cell occupied by a business can be made using the TCH on the nearest cell.

During the relationship

       The main function of the BSC during the call are:

·         Dynamic Power Control in MS and RBS: BSC take into account the needs of MS and the BTS power output based on measurements received from the uplink and downlink. It was sent to the BTS and MS every 480 ms to maintain a good relationship quality.

·         Locating: The function of locating continually evaluate the radio link to the MS and if necessary, recommend handover to another cell. This recommendation includes a list of cell-cell handover. The decision is based on the measurement of MS and BTS.

·         Handover: When the function of locating proposed that the handover took over, the BSC then decides which ones will dihandover cell and begin the process of handover. If the cell is owned by another BSC, MSC / VLR should be involved in the handover. However, in a handover, the MSC / VLR dicontrol by BSC. There is no decision-making made the MSC because there is no real-time information from the MS and BTS.

·         Frequency Hopping: 2 type hopping is supported by the BSC, namely: - Baseband Hopping: involves hopping between frequencies in different transciever in a cell.

•         Synthesiser Hopping: Engaging hopping from frequency to frequency at the same transciever in a cell.

GS	Group Switch	ETC	Exchange Terminal Circuit
CP	Central Processor	ST-7	Signalling Terminal #7
RP	Regional Processor	SP	Support Processor
SRS	Subrate Switch	TRH	Transciever Handler