Communication systems are known to support wireless and wired communications between wireless and/or wired communication devices. Such communication systems range from national and/or international cellular telephone systems to the Internet to point-to-point in-home wireless networks. Each type of communication system is designed, and hence operates, in accordance with one or more communication standards. For instance, wireless communication systems may operate in accordance with one or more standards including, but not limited to, IEEE 802.11, Bluetooth, advanced mobile phone services (AMPS), digital AMPS, global system for mobile communications (GSM), code division multiple access (CDMA), local multi-point distribution systems (LMDS), multi-channel-multi-point distribution systems (MMDS), and/or variations thereof.
Depending on the type of wireless communication system, a wireless communication device, such as a cellular telephone, two-way radio, personal digital assistant (PDA), personal computer (PC), laptop computer, and/or home entertainment equipment, communicates directly or indirectly with other wireless communication devices. For direct communications, also known as point-to-point communications, participating wireless communication devices may tune their receivers and transmitters to the same channel, or channels, such as one or more of the plurality of radio frequency (RF) carriers of the wireless communication system, and communicate over one or more of those channels. For indirect wireless communications, each wireless communication device communicates directly with an associated base station for use of cellular services, for example, and/or an associated access point for use of an in-home or in-building wireless network, for example, via an assigned channel, or channels. To complete a communication connection between the wireless communication devices, the associated base stations and/or associated access points communicate with each other directly, via a system controller, via the public switch telephone network, via the internet, and/or via some other wide area network.
For each wireless communication device to participate in a wireless communications session, it may include a built-in radio transceiver comprising a receiver and transmitter, or it may be coupled to an associated radio transceiver, such as a station for in-home and/or in-building wireless communication networks, and/or an RF modem. The transmitter may be adapted to convert data into RF signals by modulating the data in accordance with the particular wireless communication standard to produce baseband signals and mixes the baseband signal with a local oscillator signal in one or more intermediate frequency stages to produce the RF signals. The radio receiver may comprise an antenna section, a filtering section, a low noise amplifier, an intermediate frequency (IF) stage, an equalization stage, and/or a demodulator. The antenna section may receive RF signals and may provide them to the filtering section, which, in turn, may pass RF signals of interest to the low noise amplifier (LNA).
The LNA may amplify the received RF signals of interest and may provide them as amplified RF signals to the IF stage. The IF stage may step down the frequency of the RF signals of interest to an intermediate frequency or to baseband. The IF stage may then provide the intermediate frequency signals, or baseband signals, to the equalization stage. The equalization stage may add loss or delay to specific frequencies to produce a flat frequency response. The equalization stage may then output an in-phase (I) and/or a quadrature (Q) component to the demodulator. The demodulator may be adapted to synchronize the signal and/or to recapture the data in accordance with a demodulation protocol. During operation, the signal quality of a received signal may be utilized to determine how best to receive and demodulate the signal.
In some conventional systems, signal quality of an RF signal is usually estimated by using received signal strength indicator (RSSI) measurement and packet error rate (PER). However, due to interference environment, the received signal strength indicator measurement and packet error rate measurement may not provide an accurate estimation of the signal quality. During reception, due to interference, it may be difficult to determine whether a received signal is an intended received signal or interference. For example, a strong signal may be received with good signal quality, but this signal may be interference rather then the intended received signal. Furthermore, to get an accurate estimate of the packet error rate, a large enough population of packets is required and this may take a substantial amount of time.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.