D-Link DWC-1000 User Manual - Page 76

Short Guard Interval, Enable, Disable, Space Time Block Code, Radio Resource Management, No ACK,

Page 76 highlights

Wireless Controller User Manual S hort Guard Interval : Th e g u ard in t erv al is t h e d ead t ime, in n an o second s , b et ween OFDM s y mb o ls . Th e g u ard in t erv al p rev en t s In t er -Sy mb o l an d In t er-Carrier In t erferen ce (ISI, ICI). Th e 802.11n mo d e allo ws fo r a reduction in this guard interval from the a and g definition of 800 nanoseconds to 400 nanos econds . Reducing the guard interval can yield a 10% imp ro v emen t in d at a t h ro ugh p u t . Select o n e o f t h e fo llo win g o p t io n s : • Enabl e : Th e A P t ran s mit s d at a u s in g a 400 n s g u ard In t erv al wh en co mmu n icat in g wit h clien t s t h at als o s u p p o rt t h e 400 n s guard interval. • Di s abl e : Th e A P t ran s mit s d at a u s in g an 800 n s g u ard in t erv al. S pace Ti me B l ock Code : Sp ace Time Blo ck Co d in g (STBC) is an 802.11n t ech n iq ue in t ended t o imp ro v e t h e reliab ilit y o f d at a t ransmis sio ns. Th e d ata s t ream is t ran s mit t ed o n mu lt ip le an t en n as s o t h e receiv in g s y s t em h as a b et t er ch ance o f d et ect ing at least o n e o f t h e d at a s t reams . Select o n e o f t h e following options : • Enabl e : Th e A P t ran s mit s t h e s ame d at a s t ream o n mu lt ip le an t en n as at t h e s ame t ime. • Di s abl e : Th e A P d o es n o t t ran s mit s t h e s ame d at a o n mu lt ip le antennas. Radi o Res ource Manag ement: Rad io Re s o u rce M eas u remen t (RRM ) mo d e req u ires t h e W ireles s Sy s t em t o s en d ad d it io n al in fo rmat io n in b eaco n s , p ro b e res p onses, an d associat io n res p o n s es . En ab le o r d is ab le t h e s u p p o rt fo r rad io res o u rce meas uremen t feat ure in t h e A P p ro file. Th e feat u re is s et independently for each radio and is enabled by default. No ACK: Select En ab le t o s p ecify t h at t h e A P s h o u ld n o t ackn o wled g e frames wit h Qo s No A ck as t h e s erv ice clas s v alu e. Mul ti cas t Tx Rate (Mbps ): Select t h e 802.11 rat e at wh ich t h e rad io t ran s mit s mu lt icas t frames . Th e rat e is in M b p s . Th e lo wes t rat e in t h e 5 GHz b an d is 6 M b p s . 74

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Wireless Controller
User Manual
74
Short Guard Interval
: The guard interval is the dead time, in nanoseconds,
between OFDM symbols. The guard interval prevents Inter-Symbol and
Inter-Carrier Interference (ISI, ICI). The 802.11n mode allows for a
reduction in this guard interval from the a and g definition of 800
nanoseconds to 400 nanoseconds. Reducing the guard interval can yield a
10% improvement in data throughput. Select one of the following options:
Enable
: The AP transmits data using a 400 ns guard Interval
when communicating with clients that also support the 400 ns
guard interval.
Disable
: The AP transmits data using an 800 ns guard interval.
Space Time Block Code
: Space Time Block Coding (STBC) is an 802.11n
technique intended to improve the reliability of data transmissions. The data
stream is transmitted on multiple antennas so the receiving system has a
better chance of detecting at least one of the data streams. Select one of the
following options:
Enable
: The AP transmits the same data stream on multiple
antennas at the same time.
Disable
: The AP does not transmits the same data on multiple
antennas.
Radio Resource Management
: Radio Resource Measurement (RRM) mode
requires the Wireless System to send additional information in beacons,
probe responses, and association responses. Enable or disable the support
for radio resource measurement feature in the AP profile. The feature is set
independently for each radio and is enabled by default.
No ACK
: Select Enable to specify that the AP should not acknowledge
frames with QosNoAck as the service class value.
Multicast Tx Rate (Mbps)
: Select the 802.11 rate at which the radio
transmits multicast frames. The rate is in Mbps. The lowest rate in the 5
GHz band is 6 Mbps.