1. Peer Aware Communication MAC Frame Structure
<month year>
doc.: IEEE <doc#>
Peer Aware Communication MAC Frame Structure
Seong-Soon Joo*,
In-Hwan Lee, Hyo-Chan Bang
ETRI
<author>, <company>

2. MAC Frame Structure Two layered MAC frame structure
Synchronization Interval
fixed number of TDMA subslots (eg. 12 usec long, SI = 8,334 subslots = ms)
pre-assigned subslots for synchronization, peer discovery, peer group control, contention access data channel, contention free data channel slot
Superframe and Cyclic Superframe
superframe is comprised of number of sync intervals
the usage of slots of superframe is configured according to the service type
assign idle period among synchronization, discovery, control/groupcast, connectionless link, connection-oriented link period
cyclic superframe = active period(n*superframe) + inactive period(m*superframe of idle period)
Superframe (ex. active period )
Sync
Period
Discovery
Period
Control
Period CL
Period CO
Period
Sync
Period
Discovery
Period
Idle
Period
Idle
Period CO
Period
subslot
Sync
Slot
Discovery Slot
Control
Slot
CA-Data
Slot
CF-Data
Slot
Sync
Slot
Discovery Slot
Control
Slot
CA-Data
Slot
CF-Data
Slot
Synchronization Interval
Synchronization Interval
cyclic superframe
active
inactive s d c CL CO s d c CL s d s d s d s d

3. MAC Superframe superframe types for data phase of application services
type 1 (uni-directional connectionless message transmission)
advertise or discover with transmitting data
single Sync Interval (sync – discovery – idle – CL – idle period)
type 2 (bidirectional connectionless message transmission)
discover request and response with transmitting data
two Sync Interval (sync – discovery – control– CL – idle period)-(sync – discovery – idle – CL – idle period)
type 3 (delay tolerant message transmission)
establish a contention access link after discovery
(sync – discovery – control – CL – idle period)
type 4 (mixed type of traffic)
support mixed type of traffic
two Sync Interval (sync – discovery – control – CL – CO period)-(sync – discovery – idle – CL – idle period)
type 5 (reliable message transmission)
establish a guaranteed access link after discovery
(sync – discovery – control – idle – CO period)
type 6 (open configurable superframe)
select length of superframe and slot usage of sequentially appeared slots of sync intervals
advertised by superframe structure Information Element
transmission priority of slots among service types
type 6 > type 5 … > type 1

4. MAC Cyclic Superframe configuration of MAC cyclic superframe
service type, number of active superframe, number of inactive superframe
given by higher layer through MAC layer primitives
usage of MAC cyclic superframe in service phase
discovery phase : discovery slots of inactive superframe are also used
peering phase : control slots of inactive superframe are also used
data phase : follow the active superframe configuration
cyclic superframe example
service type 4, active period 1, inactive period 1
(sync – discovery – control – CL – CO period)-(sync – discovery – idle – CL – idle period)
cyclic superframe
active
inactive
discovery s d s d s d s d s d s d
peering s d c s d c s d c s d c s d c s d c
data s d c CL CO s d CL s d s d s d c CL CO s d CL

5. Distributed Resource Reservation
addressing link resource
indicates two ends of a link by peer link IDs
peer link ID = peer device ID (12bits) + peer link ID (4bits)
assign resource for a link
CAP : superframe sequential ID + CL period sequential ID
CFP : superframe sequential ID + CO period sequential ID + slot ID
distributed resource reservation during peering
reservation CL period of service type 3, 4
assign CL period of a cyclic superframe sequentially in the order of peering requests
reservation CO period of service type 4, 5, 6
source peer device of an uni-directional link
before reserving CFP slots, scan neighbor’s control slot
select superframe, CO period, and slots based on the hashed peer link ID
request to reserve slots to other end peer device by sending peering request
destination peer device of an uni-directional link
receive peering request with assigned resource for a link
check available slots by scanning neighbor’s control slot
send ack or adjusted slot assignment to source of a link

6. Distributed Interference Avoidance
interference avoidance among multiple peer groups
access control to multiple peer groups as a participant
follow the priority of service types among peer groups
access control as an initiator
select start time of the cyclic superframe
opportunistic transmission
based on designed statistical access
interference avoidance example
coexist multi peer groups
service type 3 (active 2, inactive 0) peer group
service type 4 (active 1, inactive 1) peer group
apply shorter backoff to access CL period of service type 4
cyclic superframe
service 3 peer group
data phase s d c CL s d c CL s d c CL s d c CL s d c CL
cyclic superframe
service 4 peer group
data phase s d c CL CO s d CL s d s d s d c CL CO s d CL

7. PAC MAC Frame Formats frames MAC frame header
frame control : version, frame type, dest link ID/src link ID/IE indicator
Advertise Req, Discover Req/Resp, Peer Req/Resp, DePeer Req/Resp, RePeer Req, Data
peer group ID : peer group service type (3bits) + local group ID (5bits)
peer link ID : peer device ID (12bits) + peer link ID (4bits)
peer group authenticator
MAC frame information elements
type, length, value
peer group information element : with control & management commands
MAC frame payload
MAC frame tail
frame check sequence
frames
advertise, discover req. : header (3B) + payload (var) + tail (2B)
peer req./resp : header (9B) + IE (4B) + tail (2B)
data : header (5B) + IE (3B) + payload (var) + tail (2B)
Octets: 2 1
0/2/8
0/2
0/variable 2
Frame Control
Peer Group Identifier
Destination Peer Link ID
Source Peer Link ID
Peer Group Authenticator
Peer Group Information Element
Frame Payload
Frame Check Sequence
Peer Link Addressing fields
MAC Frame Header
MAC Frame Information
MAC Frame Payload
MAC Frame Tail

8. Frame Filtering at MAC Layer
the first frame filtering
filtering all the frame
check the peer group service type
if not matched, discard
the second frame filtering
filtering all the frame except advertise, discover req., discover resp. frame
check the local group ID
the third frame filtering
check the peer device ID and peer link ID
if matched without Relaying IE, forward frames to higher layer
the fourth frame filtering
check Relaying IE
if frame arrives on correct link,
relay frames to outward device by transmitting a frame on outward link