Section 4: cdma2000 MAC Overview 1 Section 4: cdma2000 MAC Section 4: cdma2000 MAC

Section 4: cdma2000 MAC Overview 2 What cdma2000 MAC Provides The cdma2000 MAC sublayer provides: –MAC Control States - procedures for controlling the access of data services (packet and circuit) to the physical layer; –Best Effort Delivery - reasonably reliable transmission over the radio link with a Radio Link Protocol (RLP) that provides a “best effort” level of reliability; and –Multiplexing and QoS Control - enforcement of negotiated QoS levels by mediating conflicting requests from competing services and the appropriate prioritization of access requests. –Enhanced Access Procedures

Section 4: cdma2000 MAC Overview 3 Channel Naming Example: f-csch = Forward Common Signaling CHannel

Section 4: cdma2000 MAC Overview 4 Logical Channels  Dedicated Traffic Channels (dtch) –  data channel dedicated to a single PLICF instance;  Common Traffic Channels (ctch) –  data channel with shared access among many mobile stations and/or PLICF instances;  Dedicated Signaling Channels (dsch) –  Upper Layer Signaling data dedicated to a single PLICF instance; and  Common Signaling Channels (csch) –  Upper Layer Signaling data with shared access among many mobile stations and/or PLICF instances.

Section 4: cdma2000 MAC Overview 5 cdma2000 MAC State Transitions

Section 4: cdma2000 MAC Overview 6 Packet Data States Active State –Dedicated traffic channels (e.g., fundamental or supplemental) are allocated; –The Activity Timer starts when no traffic is exchanged and reset when there is traffic to be exchanged; –Traffic channel is released when the Activity Timer expires. Control Hold State –A dedicated control channel is maintained on which MAC control commands (e.g., to begin a high speed data burst) can be transmitted. –Power control is also maintained so that high speed burst operation can begin with minimum delay. –Reverse pilot may be transmitted in a “gated” mode (i.e. with a duty cycle of less than one) to reduce interference and save power

Section 4: cdma2000 MAC Overview 7 Packet Data States (cont’d) Suspended State –No dedicated channels to or from the user are maintained –The state information for RLP is maintained –Active Set is stored by the BS so that if the Active Set is not changed the BS can instruct the MS to use the stored Active Set –Service Configuration Record is stored by the BS (to avoid Service Negotiation) –Mobile may continue monitoring the Paging Channel in the non- slotted mode for a shot time interval (~ 1-2 sec) after dropping the dedicated channels. This expedites a transition to the Active State shortly after the dedicated channels are released.

Section 4: cdma2000 MAC Overview 8 Example of Packet Data State Transition

Section 4: cdma2000 MAC Overview 9 State Transition Example

Section 4: cdma2000 MAC Overview 10 cdma2000 Layered Structure

Section 4: cdma2000 MAC Overview 11 Simplified Layered Architecture

Section 4: cdma2000 MAC Overview 12 Functional Entity Definitions Signaling –Performs Channel Assignment, Service Negotiation, Handoff, etc Data Service PLICF –Interacts with the Resource Control and the Peer PLICF to coordinate state transitions between the MS and BS DCR (Dedicated/Common Router) PLICF –Controls the behavior of the BS/MS when in Dormant State MUX & QoS –realtime prioritization of the use of dedicated traffic resources –Mux/de-Muxing of the logical channels from/to different physical channels based on the Logical to Physical Mapping table (LPM)

Section 4: cdma2000 MAC Overview 13 Resource Control Locks and Unlocks resources and harmonizes state transition across multiple PLICFs Maintains a database to control the operating configuration of the mobile, including –the current logical to physical channel mapping, and –the currently defined physical channel configuration (e.g., dedicated vs. common control operation; number of active SCHs; DCCH vs. FCH; etc.). 4 = Locked blank = unlocked sr_id = Service Reference ID

Section 4: cdma2000 MAC Overview 14 State Transitions: Active State Active Control Hold

Section 4: cdma2000 MAC Overview 15 Simplified State Transitions ActiveControl HoldSuspended

Section 4: cdma2000 MAC Overview 16 Multiple Services Multiple services with different characteristics may be connected simultaneously. The Resource Control coordinates amongst multiple services State transitions are synchronized (i.e. the RC assures that all the services make the state transition at the same time) This synchronization is necessary because each state (e.g., Active, Suspended) has a certain set of attributes that correspond to the behavior of the BS/MS as a whole

Section 4: cdma2000 MAC Overview 17 Dragging Example Time PLICF A State Resource PLICF B State Resource Control Suspended Traffic... Allocate dmch, dtch Confirm Allocate Indication dmch, dtch Suspended Active dmch, dtch Active dmch, dtch... Control Hold dmch Unlock dtch Release Indication dtch Control Hold dmch PLICF B Dragged to Active... Release Indication dtch PLICF B Dragged to Control Hold... Service ‘A’ requests for a transition to Active from Suspended Service ‘B’ gets dragged up to Active as well

Section 4: cdma2000 MAC Overview 18 Dangling Example Time PLICF A State Resource PLICF B State Resource Control Control Hold dmch Timeout... Unlock dmch Release Indication dmch Control Hold dmch Suspended... Timeout... Unlock dmch Release Indication dmch PLICF A Dangling... Service ‘A’ requests for a transition to Control Hold from Suspended Service ‘A’ dangles in the Control Hold state until service ‘B’ is ready to make the transition

Section 4: cdma2000 MAC Overview 19 Multiple Services: Releasing Resources and Dangling Active State Locked Timer expires Send Request for releasing dtch Timer expires Send Request for releasing dmch Unlocked RC confirmation Unlocked RC confirmation Locked Timer expires Send Request for releasing dtch Timer expires Send Request for releasing dmch Unlocked RC confirmation Unlocked RC confirmation RC releases dmch Locked RC releases dtch Locked RC releases dtch PLICF_APLICF_B [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] Control Hold State Active Control Hold

Section 4: cdma2000 MAC Overview 20 Multiple Services: Allocating Resources and Dragging Active State Unlocked Locked RC Lock confirmation Have Data to Send Send Request for Allocating dtch Unlocked Locked Unlocked Receives Confirmation for Allocation of dtch Receives Indication for Allocation of dtch PLICF_A PLICF_B Has Data to Send Send Request for locking dtch [1] [2] [3] [2] [4] Control Hold State Control HoldActive

Section 4: cdma2000 MAC Overview 21 State Transition Procedure 1 A PLICF locking or unlocking a logical resource 2 The RC determines if the request leads to a release or allocation of a physical resource 3 If a physical resource needs to be release or allocated, then the RC instructs the L3-Signaling to allocate or release the physical resource

Section 4: cdma2000 MAC Overview 22 Mux Sublayer Data block: A block of data that belongs to the same service or signaling MuxPDU: MuxSDU + header –The header specifies the Signaling, Primary, or secondary MuxPDU Type: determines –Rate Set (e.g., 1 or 2) –how to parse the MuxPDU Mux Option: determines –max number of MuxPDUs on the SCH –Single-size or double-size MuxPDUs –Mux PDU Type LTU: Logical Transmission unit: –1, 2, 4, or 8 MuxPDUs that are protected by a CRC which is added at the MUX sublayer

Section 4: cdma2000 MAC Overview 23 PDU Types and New Mux Options Example: Mux Option 0x906: Maximum 1 double- size MuxPDU Type 3 Mux Option 0x822: Maximum 4 single- size MuxPDU Type 3

Section 4: cdma2000 MAC Overview 24 Resource Config. Database (RCD)

Section 4: cdma2000 MAC Overview 25 RRC Messages Extended Supplemental Channel Assignment Message (20 ms) –For each Supplemental Channel it specifies: »Units of Start Time »A list of Active Sets for F-SCH (PN codes, Walsh Codes, and Quasi-orthogonal functions) »Assignment Forward Supplemental Channel Assignment Mini Message (5 ms) –Specifies the Supplemental Ch. ID, Start Time, Duration, and an index to the list Active sets

Section 4: cdma2000 MAC Overview 26 RRC Messages (cont’d) Reverse Supplemental Channel Assignment Mini Message (5 ms) –Specifies the Supplemental Ch. ID, Start Time, Duration, and Rate Reverse Supplemental Channel Request Mini Message (5 ms) –Specifies the Supplemental Ch. ID, Requested Rate, and Requested Duration.

Section 4: cdma2000 MAC Overview 27 MAC Messaging (cont’d) Reverse High-Rate Transmission Forward High-Rate Transmission

Section 4: cdma2000 MAC Overview 28 Existing IS-95 A/B Access IS-95 A/B access scheme is based on a slotted aloha protocol –access channel slots are non-overlapping Accessing mobiles send probes on R-EACH: –probes consist of: »preamble portion (typically 80 ms) »message portion (typically 120 ms) Acknowledgements are transmitted on the paging channel –acknowledgement time-out (typically 320 ms) If no acknowledgement is received, mobile increases power and tries again (i.e. power ramping) –Access slotting is typically 200 ms –back-off delays (multiple of 200 ms) –persistence delay (multiple of 200 ms)

Section 4: cdma2000 MAC Overview 29 IS-95A/B Access Procedure

Section 4: cdma2000 MAC Overview 30 Requirements for Improved Access Increase System Capacity –Minimize power required to service transactions »reduce power on preamble for detection »reduce power on message portion »minimize message retransmission probability –Facilitate better flow control and admissions policies Increase Throughput & Reduce Delay –Minimize service transaction times »increased data rates (9.6, 19.2 and 38.4 kbps) »shortened preamble »reduce message error probability »reduce protocol latency (i.e. slot duration, ack. timeout, etc.)

Section 4: cdma2000 MAC Overview 31 Improved Access Methods Employ overlapped slotting –make long code a function of slot time to prevent hard collisions Improve message error rate performance –closed loop power control –employ adjustable step sizes Protocol Optimization: –reduce slot intervals, timeout params, etc. –for very short messages, closed loop PC provides little gain –closed loop PC can be used to correct gross inaccuracies in open loop estimate –longer messages can be moved to a dedicated channel –soft handoff can be used to improve access performance

Section 4: cdma2000 MAC Overview 32 Overview of Proposed Approach Reservation Multiple Access (RsMA) is composed of three distinct access protocols: –Basic Access Mode (slotted aloha): »best for very short messages (e.g. < 20 ms.) »open loop power control only »no soft handoff –Power Controlled Access Mode (PCA): »best for latency sensitive applications »closed loop power control on RL »no soft handoff –Reservation Mode (RsMA): »best for longer messages »closed loop power control on RL »soft handoff facilitated

Section 4: cdma2000 MAC Overview 33 Access Channels Forward Link: »Common Power Control Channel (F-CPCCH) »Channel Assignment Channel (F-CACH) »Common Control Channel (F-CCCH) Reverse Link: »Reservation Access Channel (R-EACH) »Common Control Channel (R-CCCH)

Section 4: cdma2000 MAC Overview 34 Reverse Reservation Access Channel Reverse Enhanced Access Channel (R-EACH) –Slotted Aloha random access channels –multiple R-EACH’s per F-CCCH R-EACH is operated in 3 primary modes: –BA Mode: short messages sent –PCA Mode: messages sent with closed loop PC –RsMA Mode: reservation requests sent Data rates supported: –9.6 kbps (20 ms frame),19.2 kbps (10, 20 ms frames), 38.4 kbps (5, 10, 20 ms frames) R-EACH Probe Structure: –BA Mode: aloha access probe (AAP) = initial preamble + message –PCA Mode: message access probe (MAP) = initial preamble + mode request frame + message –Reservation Mode: reservation access probe (EAP) = initial preamble + mode request frame

Section 4: cdma2000 MAC Overview 35 Reverse Common Control Channel Reverse Common Control Channel (R-CCCH) –Assigned dedicated access channels –Multiple R-CCCH’s supported –long code can be common or user specific (designated) Data rates supported : –9.6 kbps (20 ms frame),19.2 kbps (10, 20 ms frames), 38.4 kbps (5, 10, 20 ms frames) Soft Handoff : –2-way soft handoff can be accommodated on the R-CCCH »demod at 2 separate BTS’s »PC independently from 2 BTS’s

Section 4: cdma2000 MAC Overview 36 Forward Common Assignment Channel Forward Common Assignment Channel (F-CACH) –single Walsh code control channel supporting multiple R-EACH’s and R-CCCH’s –multiple F-CACH’s supported Modulation format: –single 128-chip Walsh code channel –DTX, QPSK –fixed 9.6 kbps; k=9, rate 1/2 conv. code –fixed 5 ms message duration with CRC Messages: –BTS-level channel assignments/acknowledgements –load & flow control (wait message)

Section 4: cdma2000 MAC Overview 37 Forward Power Control Channel Forward Power Control Channel (F-CPCCH) –multiple F-CPCCH’s supported –single Walsh code channel, divided into multiple sub-channels –Each F-CPCCH subchannel supports a single R-EACH or R-CCCH Number of PC sub-channels per F-CPCCH –depends on PC rate which is a system parameter: »800 bps PC --> 24 subchannels per F-CPCCH »400 bps PC --> 48 subchannels per F-CPCCH »200 bps PC --> 96 subchannels per F-CPCCH Modulation format: –single 128-chip Walsh code channel –DTX, uncoded QPSK –fixed 9.6 kbps bit rate per I-Q phase branch Step Sizes –Access channel specific up & down steps.

Section 4: cdma2000 MAC Overview 38 R-EACH Waveform Description Probe Preamble (sent in all modes): –integer number 1.25 ms. –preamble can be divided into multiple ‘on’ and ‘off’ pieces Mode Request Frame (not sent in Basic Access Mode) –5 ms frame, rate 1/2 coded message –Message Fields: »mode indicator (1 bit): indicates PCA vs. Reservation mode »Hash ID (16 bits):random or managed temporary mobile ID »rate word (3 bits): indicates data rate and frame length of message »neighbor PN (9 bits): PN offset of neighbor (set to 0 if no handoff requested) »CRC (8 bits) and Tail bits (8 bits) »reserved (3 bits) Message Portion (not sent in Reservation mode) –max. message duration is system parameter –rate must be consistent with rate word in Mode Request Frame

Section 4: cdma2000 MAC Overview 39 R-RCCCH Waveform Description Channel Estimation Preamble: –integer number 1.25 ms. –preamble can be divided into multiple ‘on’ and ‘off’ pieces Long Code –common long code mask –designated mode: user specific long code mask Message portion: –message is an integer number of frames –max. duration is system parameter –data rate must be consistent with resource grant –CRC’s per frame

Section 4: cdma2000 MAC Overview 40 F-CACH Waveform Description fixed messages duration (5 ms.) Single 128-chip Walsh Code channel, QPSK modulation with r=1/2, k=9 conv. Coding Channel is DTX –no message --> no power Message types: –Channel assignment message fields: –Wait message (admissions/flow control) –2 reserved message types

Section 4: cdma2000 MAC Overview 41 F-CPCCH Waveform Description PC rate determines the number of PC sub-channels supported: 800 bps, 400 bps, 200 bps. The power control sub-channel id for each F-CPCCH is partitioned as follows:

Section 4: cdma2000 MAC Overview 42 Admission/Flow Control Admission/flow control: –Slow Response Time (~ 200 ms, typical): »access parameters conveyed on F-BCCH give current persistence parameters and time-out values –Moderate Response Time ( 5 ms): »“wait message” is used to affect mobiles already accessing »sent when “overload” or “all busy” condition is near or prevailing »parameters affect: flow on both the R-EACH and R-CCCH for reservation mode traffic system loading »Inhibit Sense mode can be invoked: mobiles required to examine F-CACH prior to transmitting behavior is ISMA-like

Section 4: cdma2000 MAC Overview 43 Channel Organization R-EACH: –up to 32 per F-CCCH F-CACH: –up to 7 F-CACH’s supported R-CCCH: –up to 24 supported F-CPCCH: –up to 7 supported –PC rate determines number of sub-channels per F-CPCCH

Section 4: cdma2000 MAC Overview 44 Pure Aloha Procedures mobile “randomly” selects from the corresponding R-EACH set and transmits a Enhanced Access Probe (EAP) mobile uses persistence parameters to regulate access attempts After EAP transmitted on R-EACH, mobile monitors F-CCCH for acknowledgement: –If no ACK within time out, retry at higher power

Section 4: cdma2000 MAC Overview 45 Basic Access Mode

Section 4: cdma2000 MAC Overview 46 PCA Procedures Mobile “randomly” selects a R-EACH and transmits a Message Access Probe (MAP) conditioned on: –observed Ec/Io > T_rqst dB –“current” persistence parameters and non-blocking condition Mobile uses persistence parameters to regulate access attempts After initial MAP, mobile monitors both F-CPCCH and F-CACH: –Closed loop power control begins after parameterized delay value –Mobile looks for Channel Assignment Message containing its hash ID as confirmation of acquisition Conditions: –If no Channel Assn. Message within time-out, mobile ceases transmission of current MAP and retransmits MAP at higher power some time later –If wait message sent, cease and reretransmit MAP later –Stop transmission if either: »Ec/Io falls below T_fade for T1 seconds »Ec/Io exceeds T_good and Ec/Io of PC bits is below T_bad for L PC bits

Section 4: cdma2000 MAC Overview 47 Power Control Access Mode

Section 4: cdma2000 MAC Overview 48 Reservation Procedure (no SHO) Mobile “randomly” selects a R-EACH and transmits a Enhanced Access Probe (EAP) conditioned on: –observed Ec/Io > T_rqst dB –“current” persistence parameters and non-blocking condition Mobile uses persistence parameters to regulate access attempts After initial EAP, mobile monitors corresponding F-CACH for: –Early Ack. And Channel Assignment Message (EACAM) or Wait Message Conditions: –If no message within time-out, retransmit EAP at higher power –If wait message sent, retransmit EAP later –If channel assignment rcvd., transmit message on assigned R-CCCH at next access slot and begin closed loop power control. –Stop transmission if either: »Ec/Io falls below T_fade for T1 seconds »Ec/Io exceeds T_good and Ec/Io of PC bits is below T_bad for L PC bits

Section 4: cdma2000 MAC Overview 49 Reservation Access Mode (no SHO)

Section 4: cdma2000 MAC Overview 50 RsMA Procedure (SHO) Mobile “randomly” selects a R-EACH and transmits a Enhanced Access Probe (EAP) conditioned on: –observed Ec/Io > T_rqst dB –“current” persistence parameters and non-blocking condition Mobile uses persistence parameters to regulate access attempts After initial EAP, mobile monitors corresponding F-CCCH / F-CACH for: –EACAM Power Control Channel Assignment Message (PCCAM) to get Common PC channel and sub-channel corresponding to the neighbor BS Conditions: –If no PCCAM message within time-out, retransmit EAP at higher power –If PCCAM rcvd., transmit message on assigned R-CCCH at next access slot and begin closed loop power control using F-CPCCH subchannels indicated in PCCAM. –Stop transmission if either: »Ec/Io falls below T_fade for T1 seconds »Ec/Io exceeds T_good and Ec/Io of both PC bit streams falls below T_bad for L PC bits

Section 4: cdma2000 MAC Overview 51 RsMA Mode (w/SHO)

Section 4: cdma2000 MAC Overview 52 System Procedures System monitors R-EACH’s for messages & requests on R-EACH slot boundaries Basic Access Mode: –If EAP detected on R-EACH, system: »demodulates and decodes message »send ACK back on F-CCCH PCA Mode: –If MAP detected on R-EACH, system: »begins closed loop power control, »queue’s channel assignment message, »transmits the message in the assigned F-CACH slot(s).

Section 4: cdma2000 MAC Overview 53 System Procedures (cont.) Reservation Mode: –If EAP detected on R-EACH, system: »queue’s channel assignment/access control message, »transmits the EACAM message on F-CACH –If no SHO request-->EACAM: »system monitors the assigned R-CCCH for channel estimation preamble »If preamble detected system demodulates and power controls message portion »Else if preamble not detected system releases R-CCCH for subsequent requests and ceases sending PC bits on F-CPCCH after timeout –If SHO request -->PCCAM »system exchanges data with neighbor cell »If any base stations detect preamble, start transmitting closed loop PC bits on assigned F-CPCCH sub-channel »PCCAM sent on F-CCCH with F-CPCCH info for the neighbor BS.

Section 4: cdma2000 MAC Overview 54 Acronyms ACH: Access Channel CCCH: Common Control DCCH: Dedicated Control Channel DCR: Dedicated/Common Router DTX: Discontinuous Transmission EACAM: Early Ack & Channel Assignment Msg. EAP: Enhanced Access Probe FCH: Fundamental Channel LAC: Link Access Control MAC: Medium Access Control MAP: Message Access Probe PLIDF: Physical Layer Dependent Function RBP: Radio Burst Protocol RC: Resource Control RLP: Radio Link Protocol SCH: Supplemental Channel PCA: Power Control Access PCCAM: Power Control & Channel Assignment Msg. PCH: Paging Channel PICH: Pilot Channel PLICF: Physical Layer Independent Convergence Function