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I propose that the article add 5G-NR to the table. — Preceding unsigned comment added by 2600:1700:8750:6530:8560:8295:8FFF:98C ( talk) 18:55, 21 January 2023 (UTC)
I added D-AMPS to comparison table. some notes:
The definition could be a bit more general as it applies to more than digital. It could apply to analogue. It could apply to how spectrum is allocated by regulatory agencies.
The Shannon theorem formula should be here so that you can calculate bits per Hertz.
Telephone modem example is not strictly correct. If the bandwidth is filtered to the 3100 Hertz you will not get the 56000 bit rate through. To get that rate there will have to be less filtering. The channel will be quantized to 8 bits and so can only carry 16 bits per Hertz at the most.
"In wireless networks, the system spectral efficiency in bit/s/Hz/area unit, bit/s/Hz/cell or bit/s/Hz/site is a measure of the quantity of users or services that can be simultaneously supported by a limited radio frequency bandwidth in a defined geographic area."
This sentence packs in too many units - probably better to break it into two sentences with one unit in the first, and then an extension to the variations. Otherwise it is too confusing to read.
It would be good to add some analogue systems eg single sideband instead of AM or FM. We could have a bit of regulatory requirements. We could also have the tradeoffs, eg more power to get more signal to noise ratio, but more spectrum can reduce the power required.
In the comparason table it would be good to add some more, for example those landline modems, and some amateur digital radio schemes, some satellite transmission systems.
We could have a section on how efficiency can be improved, some techniques are mentioned in passing already.
If I can find the time I may get around to some improvements over the next few months.
GB 22:47, 24 January 2007 (UTC) --
I see that Mehwoot has had a go at recalculating the spectral efficiency of a V.92 modem. However the raw bandwidth at the exchange is 0-4000 Hertz sampled at 8 bits at 8000 samples per second. An antialias filter will reduce this bandwidth somewhat below the 4000 Hertz limit. I will confirm what the rates are for what bandwidths. The maximum data throughput that could happen would be 64000 bits per second or 16 bits per Hertz. GB 06:30, 28 January 2007 (UTC)
Good section. I like the take on bits/hz per area. This is particulary important for wireless broadband and converged wired-wireless networks.
Robert Syputa
Huh? Hz = s-1, therefore Hz-1 = s. Hence, bits * s-1 * Hz-1 = bits * s-1 * s Hence, bits/s/Hz = bits.
So, why use units of bits/s/Hz for spectral efficiency, when "bits/s/Hz" is just a confusing way of saying "bits"? —The preceding unsigned comment was added by 124.189.8.183 ( talk) 03:46, 3 March 2007 (UTC).
By the way bits/s/Hz is not a unit, it violates at least two of metric system rules. If we want to keep Hz and s (which is allowed in metric system and makes sense here), it should be written as bit/Hz·s (or bit/s·Hz).
No, bits/s/Hz = bits is incorrect. Hz is cycles per second, so Hz-1 is seconds per cycle, so bit/s/Hz is bits per cycle. But s and Hz are SI units, and cycle is not, so we say bit/s/Hz or some appropriate variant. Dicklyon ( talk) 02:57, 16 February 2008 (UTC)
Well, at least it is established in literature and publications. A Google search and Google Book Search gives:
Mange01 ( talk) 11:47, 16 February 2008 (UTC)
Revised by Mange01 ( talk) 22:47, 13 April 2008 (UTC)
Cycle measures added. Dicklyon ( talk) 08:10, 27 December 2009 (UTC)
I reverted the addition of this new variant unit. This discussion followed: Dicklyon ( talk) 08:10, 27 December 2009 (UTC)
Please vote at Talk:Eb/N0#Survey on which unit that should be used at Wikipedia for measuring Spectral efficiency. For a background discussion, see Talk:Spectral_efficiency#Bit/s/Hz and Talk:Eb/N0#Bit/s/Hz. Mange01 ( talk) 07:21, 16 April 2008 (UTC)
There was a very nasty picture that made my stomach sick when I opened this page, but it vanished before I could do anything. Did any good soul remove it, or we have a hole in Wikipedia?
There was no image link in page source. Probably reverted between the time I downloaded vandalized version and the time it was fixed. There are some very ill people out there. You have my continuing support in fighting them.
P.S.
Anyone thought of AI software that would try to establish whether the image submitted is something vulgar and notify administrators? I have a few clues to start with. Thx. -- Mtodorov 69 13:47, 7 May 2007 (UTC)
What is the spectral effiency of analog transmission modes as AM ( A3), SSB, FM, analogue TV, etc.? —Preceding unsigned comment added by 91.46.209.184 ( talk) 20:00, 15 April 2008 (UTC)
Not sure if this is the right place to put this but there is a misleading inconsistency in this page and the main wimax page [12] with regards to the spectral efficiency of wimax (802.16d), this page states an efficiency of (4.8 bit/s)/Hz but the main wimax page states for 802.16d a spectral efficiency of 3.7 (bit/s)/Hz
195.59.43.240 ( talk) 13:01, 7 May 2008 (UTC)Rob
I split the table entry for CDMA2000 1x into separate entries for voice and PD (packet data), and made some corrections to the frequency reuse and resultant calculations. Also added a new entry for CDMA2000 1x EV-DO. NX7U ( talk) 04:44, 10 June 2008 (UTC)
I'd like to add that the definition of spectral efficiency assumed on this page is not the only one in use. Another, older and still pretty common definition is the ratio between the capacity of the modulation method used and the Shannon capacity. Under this definition, BPSK has more spectral efficiency than 64-QAM, since the mutual information limit for 64-QAM is so far away from capacity. Whereas this page's definition would simply say that 64-QAM has more "efficiency" because it is sending more bits.
I think at minimum this page should specifically give a literature reference as to where the definition being used came from. —Preceding unsigned comment added by Spope3 ( talk • contribs) 22:04, 2 March 2009 (UTC)
Not sure if that is intentional, but example numbers are not consistent. Example 7 is followed by examples 6 and 7. 93.159.77.200 ( talk) 08:34, 16 July 2009 (UTC)
Maybe this is a naive question: if V.92 is so extremely efficient with spectral bandwidth (14 (bit/s)/Hz ), why is not every system exploiting V.92's modulation scheme? - Abdull ( talk) 13:16, 6 February 2010 (UTC)
Would it be a good idea to move the comparison to a template that is embedded in the end of articles about all compared systems? For example template:spectral efficiency comparison table. The table should be collapsible.
Can it be done? Mange01 ( talk) 21:08, 7 May 2010 (UTC)
We need to add one new column to the table, with Energy per bit, from were we can compare the different Carrier/Noise needed to each modulation. —Preceding unsigned comment added by 85.138.250.13 ( talk) 10:54, 22 October 2010 (UTC)
The reference to: Kolbrun Johanna Runarsdottir (2008). "Comparison of Mobile WiMAX and HSDPA" (PDF). Master of Science Thesis, Stockholm, Sweden. is a dead link now. I've tried to find it on-line, but I can't. If anyone know where to find it, please update the link.
The numbers for 3G WCDMA seems a bit strange, at least without mentioning the number of "mobiles" that can simultaneously access the system. I'd appreciate it anyone have more information about WCDMA. Haakoo ( talk) 15:27, 19 January 2011 (UTC)
How do they seem strange? Could you elaborate as I might be able to help if I knew where the "strangeness" is. WCDMA doesn't really have a hard limit as to how many users can use a cell. Especially with CS voice over HSPA, signalling on HSPA and F-DPCH and other recent advancements have come to play. Practical limits naturally do exist, but as power control can be done with 10 users on a single SF256 code, theoretical values in the downlink could be over 1000. But that's just one limiting factor. Noise from multiple users etc. come into play far sooner. Nasula ( talk) 15:53, 19 January 2011 (UTC)
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I propose that the article add 5G-NR to the table. — Preceding unsigned comment added by 2600:1700:8750:6530:8560:8295:8FFF:98C ( talk) 18:55, 21 January 2023 (UTC)
I added D-AMPS to comparison table. some notes:
The definition could be a bit more general as it applies to more than digital. It could apply to analogue. It could apply to how spectrum is allocated by regulatory agencies.
The Shannon theorem formula should be here so that you can calculate bits per Hertz.
Telephone modem example is not strictly correct. If the bandwidth is filtered to the 3100 Hertz you will not get the 56000 bit rate through. To get that rate there will have to be less filtering. The channel will be quantized to 8 bits and so can only carry 16 bits per Hertz at the most.
"In wireless networks, the system spectral efficiency in bit/s/Hz/area unit, bit/s/Hz/cell or bit/s/Hz/site is a measure of the quantity of users or services that can be simultaneously supported by a limited radio frequency bandwidth in a defined geographic area."
This sentence packs in too many units - probably better to break it into two sentences with one unit in the first, and then an extension to the variations. Otherwise it is too confusing to read.
It would be good to add some analogue systems eg single sideband instead of AM or FM. We could have a bit of regulatory requirements. We could also have the tradeoffs, eg more power to get more signal to noise ratio, but more spectrum can reduce the power required.
In the comparason table it would be good to add some more, for example those landline modems, and some amateur digital radio schemes, some satellite transmission systems.
We could have a section on how efficiency can be improved, some techniques are mentioned in passing already.
If I can find the time I may get around to some improvements over the next few months.
GB 22:47, 24 January 2007 (UTC) --
I see that Mehwoot has had a go at recalculating the spectral efficiency of a V.92 modem. However the raw bandwidth at the exchange is 0-4000 Hertz sampled at 8 bits at 8000 samples per second. An antialias filter will reduce this bandwidth somewhat below the 4000 Hertz limit. I will confirm what the rates are for what bandwidths. The maximum data throughput that could happen would be 64000 bits per second or 16 bits per Hertz. GB 06:30, 28 January 2007 (UTC)
Good section. I like the take on bits/hz per area. This is particulary important for wireless broadband and converged wired-wireless networks.
Robert Syputa
Huh? Hz = s-1, therefore Hz-1 = s. Hence, bits * s-1 * Hz-1 = bits * s-1 * s Hence, bits/s/Hz = bits.
So, why use units of bits/s/Hz for spectral efficiency, when "bits/s/Hz" is just a confusing way of saying "bits"? —The preceding unsigned comment was added by 124.189.8.183 ( talk) 03:46, 3 March 2007 (UTC).
By the way bits/s/Hz is not a unit, it violates at least two of metric system rules. If we want to keep Hz and s (which is allowed in metric system and makes sense here), it should be written as bit/Hz·s (or bit/s·Hz).
No, bits/s/Hz = bits is incorrect. Hz is cycles per second, so Hz-1 is seconds per cycle, so bit/s/Hz is bits per cycle. But s and Hz are SI units, and cycle is not, so we say bit/s/Hz or some appropriate variant. Dicklyon ( talk) 02:57, 16 February 2008 (UTC)
Well, at least it is established in literature and publications. A Google search and Google Book Search gives:
Mange01 ( talk) 11:47, 16 February 2008 (UTC)
Revised by Mange01 ( talk) 22:47, 13 April 2008 (UTC)
Cycle measures added. Dicklyon ( talk) 08:10, 27 December 2009 (UTC)
I reverted the addition of this new variant unit. This discussion followed: Dicklyon ( talk) 08:10, 27 December 2009 (UTC)
Please vote at Talk:Eb/N0#Survey on which unit that should be used at Wikipedia for measuring Spectral efficiency. For a background discussion, see Talk:Spectral_efficiency#Bit/s/Hz and Talk:Eb/N0#Bit/s/Hz. Mange01 ( talk) 07:21, 16 April 2008 (UTC)
There was a very nasty picture that made my stomach sick when I opened this page, but it vanished before I could do anything. Did any good soul remove it, or we have a hole in Wikipedia?
There was no image link in page source. Probably reverted between the time I downloaded vandalized version and the time it was fixed. There are some very ill people out there. You have my continuing support in fighting them.
P.S.
Anyone thought of AI software that would try to establish whether the image submitted is something vulgar and notify administrators? I have a few clues to start with. Thx. -- Mtodorov 69 13:47, 7 May 2007 (UTC)
What is the spectral effiency of analog transmission modes as AM ( A3), SSB, FM, analogue TV, etc.? —Preceding unsigned comment added by 91.46.209.184 ( talk) 20:00, 15 April 2008 (UTC)
Not sure if this is the right place to put this but there is a misleading inconsistency in this page and the main wimax page [12] with regards to the spectral efficiency of wimax (802.16d), this page states an efficiency of (4.8 bit/s)/Hz but the main wimax page states for 802.16d a spectral efficiency of 3.7 (bit/s)/Hz
195.59.43.240 ( talk) 13:01, 7 May 2008 (UTC)Rob
I split the table entry for CDMA2000 1x into separate entries for voice and PD (packet data), and made some corrections to the frequency reuse and resultant calculations. Also added a new entry for CDMA2000 1x EV-DO. NX7U ( talk) 04:44, 10 June 2008 (UTC)
I'd like to add that the definition of spectral efficiency assumed on this page is not the only one in use. Another, older and still pretty common definition is the ratio between the capacity of the modulation method used and the Shannon capacity. Under this definition, BPSK has more spectral efficiency than 64-QAM, since the mutual information limit for 64-QAM is so far away from capacity. Whereas this page's definition would simply say that 64-QAM has more "efficiency" because it is sending more bits.
I think at minimum this page should specifically give a literature reference as to where the definition being used came from. —Preceding unsigned comment added by Spope3 ( talk • contribs) 22:04, 2 March 2009 (UTC)
Not sure if that is intentional, but example numbers are not consistent. Example 7 is followed by examples 6 and 7. 93.159.77.200 ( talk) 08:34, 16 July 2009 (UTC)
Maybe this is a naive question: if V.92 is so extremely efficient with spectral bandwidth (14 (bit/s)/Hz ), why is not every system exploiting V.92's modulation scheme? - Abdull ( talk) 13:16, 6 February 2010 (UTC)
Would it be a good idea to move the comparison to a template that is embedded in the end of articles about all compared systems? For example template:spectral efficiency comparison table. The table should be collapsible.
Can it be done? Mange01 ( talk) 21:08, 7 May 2010 (UTC)
We need to add one new column to the table, with Energy per bit, from were we can compare the different Carrier/Noise needed to each modulation. —Preceding unsigned comment added by 85.138.250.13 ( talk) 10:54, 22 October 2010 (UTC)
The reference to: Kolbrun Johanna Runarsdottir (2008). "Comparison of Mobile WiMAX and HSDPA" (PDF). Master of Science Thesis, Stockholm, Sweden. is a dead link now. I've tried to find it on-line, but I can't. If anyone know where to find it, please update the link.
The numbers for 3G WCDMA seems a bit strange, at least without mentioning the number of "mobiles" that can simultaneously access the system. I'd appreciate it anyone have more information about WCDMA. Haakoo ( talk) 15:27, 19 January 2011 (UTC)
How do they seem strange? Could you elaborate as I might be able to help if I knew where the "strangeness" is. WCDMA doesn't really have a hard limit as to how many users can use a cell. Especially with CS voice over HSPA, signalling on HSPA and F-DPCH and other recent advancements have come to play. Practical limits naturally do exist, but as power control can be done with 10 users on a single SF256 code, theoretical values in the downlink could be over 1000. But that's just one limiting factor. Noise from multiple users etc. come into play far sooner. Nasula ( talk) 15:53, 19 January 2011 (UTC)