Hardware/software complexity: FDA with constant element spacing may not be an ideal configuration due to the frequency diversity
. We can employ larger element spacing to reduce the array complexity.
CSI contains both amplitude and phase measurements separately for each OFDM subcarrier, which reflects the varying multipath reflection caused by people's existence due to its significant frequency diversity
. Compared with RSS, CSI provides fine-grained channel information in the physical layer, which can now be read from modified device drivers for several off-the-shelf WiFi network interface cards (NIC), such as the Intel WiFi Link 5300 NIC  and the Atheros AR9580 chipset .
In this paper, we combine the multiple-input multiple-output (MIMO) concept with the sparse spectrum signal and convert the temporal frequency diversity
to spatial frequency diversity
Under the interference of background, research has shown that the time and frequency diversity
of frequency hopping signal, if proper frequency coding, can get good time delay and Doppler resolution features.
To achieve diversity communication, several communication techniques, for instance, micro diversity, macro diversity, space diversity, frequency diversity
and time diversity have been used .
It can also receive data using one or two bands from the same source, a frequency diversity
technique that helps to overcome a range of nuisances including interference, interruptions to the line of sight, multipath interference and platform shading.
MC-CDMA system combines the robustness to multipath fading accomplished by orthogonal frequency division multiplexing (OFDM) with the enhanced frequency diversity
and narrowband interference rejection capability that can be achieved by code division multiple access (CDMA).
* Time diversity, frequency diversity
, and physical diversity.
Sharjah TV's newly acquired wireless system consists of six channels of AXT400 receiver units, six AXT100 Axient Bodypack Transmitters and four AXT200 Axient Handheld Frequency Diversity
Transmitters with KSM9 capsule.
is a diversity method where the information signal is transmitted on L carriers.
CDD transforms a multiple-input single-output (MISO) channel into an equivalent single-input single-output (SISO) channel with increased frequency-selectivity so that the available spatial diversity is transformed into additional frequency diversity
. However, the increased frequency selectivity of channel characteristic can be a problem for post fast Fourier transform (FFT) estimation such as the channel estimation and frequency offset estimation -.