Please give me the basic idea about these channels. Which one is better for increasing throughput?
I see orthogonality as the following:
Two transmissions are orthogonal if they have no influence on one another. This can be achieved in four domains: time, space, frequency and code.
With regards to regular ZigBee I follow the opinion of Jun Luo: All channels can be considered as orthogonal channels. (5MHz channel separation and BW of 2 MHz with relatively low sideband noise). Packetloss can occur only in situations where a transmitter is located very closely to a receiver which in turn receives a low power signal. Such a situation typically only occurs when you want to do multihop communication with multiple radios per device.
hope this helps you
see the attached paper for details. orthogonal channels are designed like in OFDM to save bandwidth. In WSN non-orthogonal channels which are not orthogonal can give better performance. orthogonality is achieved by separating frequencies like in OFDM with a minimum frequency spacing
Dear sir,
I already read the same paper. The paper is good to study the concept of non-orthogonal channels. But now I need to develop it on the simulator i.e. NS2. Will it be possible to simulate it as they have designed it on the Testbed using MicaZ motes.
Thanks
Orthogonal channel: Consider you are transmitting two signals using same frequency. There will be interferance between these two sinals if they are not orthogonal. Orthogonality means both signal is having phase difference of 90 degree. Hence, it will not interfere each other. Just like CDMA, all the channels are orthogonal and hence we can use same frequency allocation for all users but signals are decoded based on PN sequence which is used for spreading the signal.
Orthogonal signalling uses carriers which do not correlate with each other (inner product or mean of mutual multiplication is zero). In case of non-dispersive channel this signalling is very efficient, since there is no interference between carriers. However, most of real-life channels are dispersive and inter-carrier interference is present. Moreover, orthogonal signalling is much more sensitive to synchronization errors than non-orthogonal one.
Dear Sir,
Suppose we are talking about the ZigBee standard where the channel center frequency distance is 5MHz. If we want to change the frequency to 3 MHz despite co-channel and inter channel interference then is it useful for me to improve the throughput? Can we say it as a Non-orthogonal channel as we are nearly using the same frequency?
Thanks
2.4GHz zegbee use direct-sequence spread spectrum. Changing bandwidth of the channel will not help. Way how PN sequences are generated is important.
For example, if you have 100 samples long PN sequence, then it is possible to generate exactly 100 mutually orthogonal sequences and therefore provide 100 concurrent transmissions on the same frequency. (Please notice, that there are infinite number of variants how to generate those 100 sequences). Now, if you relax orthogonality condition, you can generate let's say 200 _approximately_ orthogonal sequences and increase number of concurrent transmissions.
If you refer to my paper at https://www.researchgate.net/publication/256456879_FAVOR_Frequency_Allocation_for_Versatile_Occupancy_of_spectRum_in_Wireless_Sensor_Networks?ev=prf_pub , you shall find that it doesn't make too much sense to distinguish between orthorgonal and non-orthorgonal in ZigBee (though this distinction makes sense under WiFi for now).
Conference Paper FAVOR: Frequency Allocation for Versatile Occupancy of spect...
I see orthogonality as the following:
Two transmissions are orthogonal if they have no influence on one another. This can be achieved in four domains: time, space, frequency and code.
With regards to regular ZigBee I follow the opinion of Jun Luo: All channels can be considered as orthogonal channels. (5MHz channel separation and BW of 2 MHz with relatively low sideband noise). Packetloss can occur only in situations where a transmitter is located very closely to a receiver which in turn receives a low power signal. Such a situation typically only occurs when you want to do multihop communication with multiple radios per device.
hope this helps you
I suspect the answer is non-orthogonal: based on probability of mutual interference is low. ie, non-orthogonal implies there will be interference. but if most of the time it is negligible, then perhaps non-orthogonality will mean you can squeeze more waveform simultaneously at the same time,
Hello, Orthogonal signalling uses carriers which do not correlate with each other. In case of non-discursive channel this signalling is very efficient, since there is no interference between carriers. Non- orthogonal will provide multiple results and better in the wireless connectivity.
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