Ø 4 Parameters
o Service precedence
§ 3 Classes
o Reliability parameter
§ 3 Classes
o Delay parameters
§ 4 Classes
o Through parameter
§ Maximum and mean bit rates
Ø QoS profile is included in Packet Data Protocol (PDP) context
Ø Negotiation managed through PDP procedures (activation, modification and deactivation)
HSCSD: (High Speed Circuit Switched Data)
Ø Works in circuit switch mode.
Ø Speed increased by allowing single user to use consecutive time slots in GSM standard
Ø Relaxes error control coding algorithms specified in GSM increasing data rate from 9.600 to 14.400 Kbps
Ø By using 4 slots, raw data rate of up to 57.6 kbps to individual user.
Ø Ideal for dedicated streaming or real-time interactive web sessions.
EDGE: (Enhanced Data rates for GSM Evolution) (2.75 G)
Ø More advanced upgrade to 2G that requires addition of new hardware and software
Ø Developed as a path to become eventual 3G high speed data access
Ø New modulation 8-PSK in addition to GSM standard GMSK.
Ø Allows nine different formats known as Multiple modulation and Coding Scheme(MCS)
Ø Each state may either use GMSK (low rate) or 8-PSK (high rate).
Ø A family of MCS for each GSM slot and users can adaptively determine best MCS setting
Ø User start first with max error protection and max data rate until the link has unacceptable outage or delay
Ø By combining different channels (multi-carrier trans), EDGE provides upto several megabits per second data throughput.
IS-95 Reverse Link:
Ø Consists of upto 94 logical channels each occupying same bandwidth of 1228 KHz.
Ø It supports 32 access channels and 62 traffic channels
Ø Access channel is used to initiate a call, to respond to paging channel and for location update.
Ø In reverse, convolutional encoder has a rate of 1/3, thus tripling the effective rate to a max of 28.8 kbps
Near –far Problem:
Ø Signals closer to the receiver are received with less attenuation than signals farther away
Identifiers in the GSM Network:
Ø GSM uses several identifiers for
o The routing of calls
o Identifying subscribers (e.g. for charging)
o Locating the HLR, identifying equipment, etc.
Ø International Mobile Subscriber Identity (IMSI)
o It is embedded on the SIM card and is used to identify a subscriber.
Ø International Mobile Equipment identifier
o IMEI is used to identify the ME
Ø Mobile Station Roaming Number
o MSRN is used in the GSM network for routing a call to a MS.
Ø Mobile Station Integrated Services Digital Network Number (MSISDN Number)
o The MSISDN is used to identify the subscriber when, among other things, establishing a call to that subscriber or sending an SMS to that subscriber.
Absolute bandwidth:
Ø Width of the spectrum of a signal
Effective bandwidth:
Ø Narrow band of frequencies that most of the signal’s energy is contained in
Logical Channels:
Ø Mapped by the MAC to physical channels
Ø Control channels for control, synchronization and signaling
o Common
o Broadcast
o Dedicated
Ø Packet Traffic channels
o Encoded speech
o Encoded data
Reservation ALOHA:
Ø Adv:
o Higher throughput under heavy loads
o Max throughput upto 80% of channel capacity
Ø Dis-Adv:
o More demanding on users as they have to obtain / keep ‘reservation list’ up-to-date.
BCH Codes:
Ø BCH à Discoverer: Bose, Chaudhuri and Hocquenghem
Ø Multiple error correcting codes
Ø Generalization of Hamming Code
Ø Flexibility in choice of parameters
o Block length, code rate
Ø Working:
o For positive pair of integers m and t,
§ a(n, k)
o BCH code has parameters
§ Block length: n= 2m-1
§ Number of check bits: n-k <=mt
§ Minimum distance: dmin>=2t+1
o Correct combinations of t or fewer errors
o The generator polynomial can be constructed from the factors of (X2m-1+1)
Call Routing in GSM:
A/Gb mode:
Ø Class A: MS can operate simultaneous packet switched and circuit switched services
Ø Class B: MS can operate either one at one time
o Most common for handsets today
Ø Classs C: MS can operate only packet switched services
o E.g. expansion cards for laptops
Cell Splitting: -
Ø Achieve ‘capacity improvement’ by decreasing R and keeping D/R (cell reuse ratio) unchanged
Ø Divide the congested cells into smaller cells
o Smaller cells are called micro cells
Ø If radius of cell is cut to half, approximately four cells would be required
o Increased number of cells would increase the number of clusters, which in turn increase the capacity
Ø Allows a system to grow by replacing larger cells with smaller cells without upsetting the allocation scheme
Sectoring:
Ø Keep cell radius unchanged and decrease D/R
Ø Increases SIR so that cluster size may be reduced
o SIR is improved using directional antennas
o Hence increasing frequency reuse without changing transmission power
Ø Cell is partitioned into 3 120o sectors or 6 60o sectors
Cluster:
Ø N cells, which collectively use the complete set of available frequencies
Ø If a cluster is replicated M times in the system, the number of duplex channels C as a measure of capacity is C= MkN= MS
Ø So capacity is directly proportional to the replication factor in a fixed area.
Ø Clusters are inversely proportion to N
o Capacity is directly proportional to ClustersQoS Profile for GPRS Bearers
Ø 4 Parameters
o Service precedence
§ 3 Classes
o Reliability parameter
§ 3 Classes
o Delay parameters
§ 4 Classes
o Through parameter
§ Maximum and mean bit rates
Ø QoS profile is included in Packet Data Protocol (PDP) context
Ø Negotiation managed through PDP procedures (activation, modification and deactivation)
HSCSD: (High Speed Circuit Switched Data)
Ø Works in circuit switch mode.
Ø Speed increased by allowing single user to use consecutive time slots in GSM standard
Ø Relaxes error control coding algorithms specified in GSM increasing data rate from 9.600 to 14.400 Kbps
Ø By using 4 slots, raw data rate of up to 57.6 kbps to individual user.
Ø Ideal for dedicated streaming or real-time interactive web sessions.
EDGE: (Enhanced Data rates for GSM Evolution) (2.75 G)
Ø More advanced upgrade to 2G that requires addition of new hardware and software
Ø Developed as a path to become eventual 3G high speed data access
Ø New modulation 8-PSK in addition to GSM standard GMSK.
Ø Allows nine different formats known as Multiple modulation and Coding Scheme(MCS)
Ø Each state may either use GMSK (low rate) or 8-PSK (high rate).
Ø A family of MCS for each GSM slot and users can adaptively determine best MCS setting
Ø User start first with max error protection and max data rate until the link has unacceptable outage or delay
Ø By combining different channels (multi-carrier trans), EDGE provides upto several megabits per second data throughput.
IS-95 Reverse Link:
Ø Consists of upto 94 logical channels each occupying same bandwidth of 1228 KHz.
Ø It supports 32 access channels and 62 traffic channels
Ø Access channel is used to initiate a call, to respond to paging channel and for location update.
Ø In reverse, convolutional encoder has a rate of 1/3, thus tripling the effective rate to a max of 28.8 kbps
Near –far Problem:
Ø Signals closer to the receiver are received with less attenuation than signals farther away
Identifiers in the GSM Network:
Ø GSM uses several identifiers for
o The routing of calls
o Identifying subscribers (e.g. for charging)
o Locating the HLR, identifying equipment, etc.
Ø International Mobile Subscriber Identity (IMSI)
o It is embedded on the SIM card and is used to identify a subscriber.
Ø International Mobile Equipment identifier
o IMEI is used to identify the ME
Ø Mobile Station Roaming Number
o MSRN is used in the GSM network for routing a call to a MS.
Ø Mobile Station Integrated Services Digital Network Number (MSISDN Number)
o The MSISDN is used to identify the subscriber when, among other things, establishing a call to that subscriber or sending an SMS to that subscriber.
Absolute bandwidth:
Ø Width of the spectrum of a signal
Effective bandwidth:
Ø Narrow band of frequencies that most of the signal’s energy is contained in
Logical Channels:
Ø Mapped by the MAC to physical channels
Ø Control channels for control, synchronization and signaling
o Common
o Broadcast
o Dedicated
Ø Packet Traffic channels
o Encoded speech
o Encoded data
Reservation ALOHA:
Ø Adv:
o Higher throughput under heavy loads
o Max throughput upto 80% of channel capacity
Ø Dis-Adv:
o More demanding on users as they have to obtain / keep ‘reservation list’ up-to-date.
BCH Codes:
Ø BCH à Discoverer: Bose, Chaudhuri and Hocquenghem
Ø Multiple error correcting codes
Ø Generalization of Hamming Code
Ø Flexibility in choice of parameters
o Block length, code rate
Ø Working:
o For positive pair of integers m and t,
§ a(n, k)
o BCH code has parameters
§ Block length: n= 2m-1
§ Number of check bits: n-k <=mt
§ Minimum distance: dmin>=2t+1
o Correct combinations of t or fewer errors
o The generator polynomial can be constructed from the factors of (X2m-1+1)
Call Routing in GSM:
A/Gb mode:
Ø Class A: MS can operate simultaneous packet switched and circuit switched services
Ø Class B: MS can operate either one at one time
o Most common for handsets today
Ø Classs C: MS can operate only packet switched services
o E.g. expansion cards for laptops
Cell Splitting: -
Ø Achieve ‘capacity improvement’ by decreasing R and keeping D/R (cell reuse ratio) unchanged
Ø Divide the congested cells into smaller cells
o Smaller cells are called micro cells
Ø If radius of cell is cut to half, approximately four cells would be required
o Increased number of cells would increase the number of clusters, which in turn increase the capacity
Ø Allows a system to grow by replacing larger cells with smaller cells without upsetting the allocation scheme
Sectoring:
Ø Keep cell radius unchanged and decrease D/R
o SIR is improved using directional antennas
o Hence increasing frequency reuse without changing transmission power
Ø Cell is partitioned into 3 120o sectors or 6 60o sectors
Cluster:
Ø N cells, which collectively use the complete set of available frequencies
Ø If a cluster is replicated M times in the system, the number of duplex channels C as a measure of capacity is C= MkN= MS
Ø So capacity is directly proportional to the replication factor in a fixed area.
Ø Clusters are inversely proportion to N
o Capacity is directly proportional to Clusters