Browse Prior Art Database

Efficient Group Acknowledgement Scheduling in Wireless Data Links

IP.com Disclosure Number: IPCOM000112277D
Original Publication Date: 1994-Apr-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 71K

Publishing Venue

IBM

Related People

Natarajan, KS: AUTHOR

Abstract

In packet data radio communications systems, in which a base station serves as an access point to a wire- or optical fiber-based backbone network, it is often the case that the base station has several packets to send to the mobile units in its coverage area. There may be packets for more than one mobile unit. Because of the possibility that a given packet may not reach its destination, either because of interference or because of temporarily poor radio propagation, it is desirable for the mobile unit to acknowledge receipt of a packet immediately. If this immediate acknowledgement is not received at the base station, it may repeat the packet transmission.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Efficient Group Acknowledgement Scheduling in Wireless Data Links

      In packet data radio communications systems, in which a base
station serves as an access point to a wire- or optical fiber-based
backbone network, it is often the case that the base station has
several packets to send to the mobile units in its coverage area.
There may be packets for more than one mobile unit.  Because of the
possibility that a given packet may not reach its destination, either
because of interference or because of temporarily poor radio
propagation, it is desirable for the mobile unit to acknowledge
receipt of a packet immediately.  If this immediate acknowledgement
is not received at the base station, it may repeat the packet
transmission.

      But it is the case in radio systems that some period of time
must elapse between the conclusion of reception of a packet and the
commencement of the transmission of its acknowledgement.  Simpler,
less expensive radio designs lengthen this period.  If packets are
short, and this period is long, a serious degradation of channel
capacity can result, because either the base or the mobile stations
will be spending inordinate amounts of time waiting for their radios
to switch.  The disclosed invention minimizes the penalty of this
switching time.

      Suppose that the average time a packet spends during
transmission is P, and that the average time an acknowledgement
spends is A, and that the time a radio takes from transmission to
reception (or vice versa) is T. Then the proportion of time spent in
actual data transmission is P/(P+T+A+T).  This is because the time T
must elapse between the end of packet reception and the commencement
of acknowledgement transmission, and also between the end of
acknowledgement transmission and the commencement of the transmission
of the next packet.

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