A communications system transfers information between a source and a destination. Generally, a communications system includes a transmitter and a receiver which transmit and receive information signals over some media. This media may be cable wiring or atmosphere. When communications occur over atmosphere, or airwaves, they are commonly referred to as "wireless" communications. Examples of wireless communications systems include digital cellular, packet data, paging and digital cordless telephones, wireless modems, wireless local and wide area networks, digital satellite communications and personal communications networks.
Inherent in some wireless communications systems is equipment mobility. In other words, since the communication media is air, wireless communications equipment may be portable. If the equipment is portable, this communication equipment must provide its own source of power, such as a battery unit.
In order to increase utility of such portable wireless communications equipment, recent efforts have focused on lowering the DC power consumption of the circuitry. By lowering the DC power consumption, the unit's size may be reduced and/or the unit's battery life may be extended. One prior art technique for reducing the power consumption of the circuitry in portable wireless communications equipment is referred to as duty cycling. Conventional duty cycling provides power to a transmitter or a receiver at periodic intervals for a predetermined amount of time. During this time interval, data is sent or received by the transmitter and receiver respectively. The amount of time that the unit is powered depends on the system protocol. Duty cycling is useful when the data being transferred need not be sent continuously and provides power savings proportional to the ratio of the on-time to the off-time.
Presently, in digital communications systems, the receiving or transmitting circuitry is powered continuously during data reception or transmission. That is, even though a transmitter or receiver employs duty cycling, power is being consumed continuously during the periodic intervals. The narrow bandwidth of the available radio frequency spectrum limits the data transmission in a wireless communications systems to rates which are generally much lower than what would otherwise be processable given the speed of the portable unit's internal circuitry. Because of this, much of the power that is consumed during transmission and reception is wasted. Therefore, it is desirable in a digital communications systems to reduce this waste by taking advantage of the circuitry speed.
The present invention provides a digital communications system that has reduced power consumption in digital communications applications. The present invention reduces power consumption during reception or transmission using the speed of the internal circuitry of the communications unit.