From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pj1-x1036.google.com (mail-pj1-x1036.google.com [IPv6:2607:f8b0:4864:20::1036]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 8A2CE3B29D for ; Tue, 4 Jun 2024 14:51:42 -0400 (EDT) Received: by mail-pj1-x1036.google.com with SMTP id 98e67ed59e1d1-2c24109aca8so1792034a91.1 for ; Tue, 04 Jun 2024 11:51:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ieee.org; s=google; t=1717527102; x=1718131902; darn=lists.bufferbloat.net; h=references:to:cc:in-reply-to:date:subject:mime-version:message-id :from:from:to:cc:subject:date:message-id:reply-to; bh=J+u7+gcciKWWBUU3UM6Lud3uY4d5cCeNqk24PX+RHuY=; b=HKbjmLB+ZghZggWppw/EzX8QuXfxtyhoQhGJON7Rbd+Tnxt3M5fzvP1o294++qShdf 0BwDMfpwUe/VkJZUvWQLVKc8/leZuUB5Wn4agHA94wEp8m5pKZtMcZZyIi8QaupF+aFq bVwWjDY9imuRwLR3OLWxdqVx+f4hC0sWD7fmE= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1717527102; x=1718131902; h=references:to:cc:in-reply-to:date:subject:mime-version:message-id :from:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=J+u7+gcciKWWBUU3UM6Lud3uY4d5cCeNqk24PX+RHuY=; b=szI/eaM0BLWVIAQSr0NW/PO4s2kEHBQnpaKzbFWH8cXSlar8P4l/8BFewoT8J+27zn +7glUiOt2+tFAEVfm3hLUqCgw4Yc+HQvUQXvsNEb8h9lkOriJr+HABtxfU2OQEbE7OiY GVuS8XsiG6V4GOdzZIArCsC+SZytydn62Ftf/uJy/Nggki+o4UaoVqTzMWq44bCzarSD f6ESwViH+5CKEJpbUuZtOHMKkonv5UPp5mj0zLNXP+3fCcGStuWzQpIuJvys7szcvmfD vc0Fl/8wlKS8l9YOEVsKmaObYYjD8NmH74u+i7EuDldddUuyF/sp4l70BSitSJuZpjmZ b5Xw== X-Forwarded-Encrypted: i=1; AJvYcCWyCapzNK9xHnI02aaNV+feye88fmvanayAf0XXRvKxAnPpDMj8w+HR4gSocZ4OnjQwDqksnz6RYRI0gQH6fVIeh3TFBgK8oav1Ec/FPoY= X-Gm-Message-State: AOJu0Ywfu77OP7m88m+PC5w9NJAn09zzcBnG2SiB4EhVWAIx/WeqFeG6 NSbEMtIcaSJyU5RgNNHoK6W8DggR2jUvJpKxaCAxaQkHlBV6c94cHW5qJDaIcw== X-Google-Smtp-Source: AGHT+IG29cOSdlB1+3AQwXiSwVHjPV1qdnneaiUAp7qx0zaPM+8CKe66bmlaI5ls7vd3ulueDTROqg== X-Received: by 2002:a17:90b:8c4:b0:2c2:1bb4:f1a9 with SMTP id 98e67ed59e1d1-2c27db0d307mr338913a91.18.1717527101286; Tue, 04 Jun 2024 11:51:41 -0700 (PDT) Received: from smtpclient.apple (dhcp-72-253-192-210.hawaiiantel.net. [72.253.192.210]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2c1c27ec844sm8469997a91.33.2024.06.04.11.51.40 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Tue, 04 Jun 2024 11:51:40 -0700 (PDT) From: Eugene Y Chang Message-Id: <7781D8A8-370F-42BB-BDC4-7B227DFC9313@ieee.org> Content-Type: multipart/signed; boundary="Apple-Mail=_867B2639-0B4D-4F3B-A323-EC8AB4010792"; protocol="application/pgp-signature"; micalg=pgp-sha256 Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3696.120.41.1.8\)) Date: Tue, 4 Jun 2024 08:51:37 -1000 In-Reply-To: <19oo3244-56r9-p310-3005-976081o73n34@ynat.uz> Cc: Eugene Y Chang , Ulrich Speidel , Dave Taht via Starlink To: David Lang References: <32AD770E-336E-4CF4-8B1B-8AE7353981CC@ieee.org> <030p06nr-4169-9341-nn73-4n06nprp9863@ynat.uz> <3F548B50-D476-4E54-B18E-3418978105CE@ieee.org> <1703d7c4-a2f1-4f96-9e3c-85b34e35c448@auckland.ac.nz> <19oo3244-56r9-p310-3005-976081o73n34@ynat.uz> X-Mailer: Apple Mail (2.3696.120.41.1.8) Subject: Re: [Starlink] SpaceX/Starlink says it's ready for a fall satellite-to-cell service with T-Mobile X-BeenThere: starlink@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: "Starlink has bufferbloat. Bad." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 04 Jun 2024 18:51:42 -0000 --Apple-Mail=_867B2639-0B4D-4F3B-A323-EC8AB4010792 Content-Type: multipart/alternative; boundary="Apple-Mail=_4EBD8687-34E6-4261-AC7D-131CBB6C77E3" --Apple-Mail=_4EBD8687-34E6-4261-AC7D-131CBB6C77E3 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 > so it really is going to be low bandwidth for emergancy use or VERY = rural uses Or to drive (unrealistic) consumer demand =E2=80=A6.. Gene ---------------------------------------------- Eugene Chang eugene.chang@ieee.org > On Jun 4, 2024, at 8:10 AM, David Lang via Starlink = wrote: >=20 > And we have statements that the direct to satellite cell service = SpaceX is rolling out will have very large cells, even with the large = antennas on the satellites. >=20 > I seem to remember something about cells beitn 70 miles or so large. >=20 > so it really is going to be low bandwidth for emergancy use or VERY = rural uses >=20 > David Lang >=20 > Ulrich Speidel wrote: >=20 >> Yep. Getting 17 Mb/s from a single satellite to a single cellphone is = one thing. But serving multiple/many users is a different story. Because = if that's what you want to do, you only have a few options: >>=20 >> * Share the beam capacity between them - everyone gets a slice. >> * Have more (and smaller) beams, so the same frequency can be used in >> parallel for multiple users. This requires more and larger antennas >> on the satellite. >> * Up EIRP to get more power down to Earth. This requires larger >> antennas on the satellite. >>=20 >> As a general rule, when it comes to having sharp beams, both antenna = gain (for a fixed size antenna) and path loss between spacecraft and = ground increase with the square of the carrier frequency. Antenna gain = helps us to get a nice signal at the receiver, path loss works against = us in this sense. We have one antenna at each end - and gains multiply - = so that gives us a term that's proportional to frequency to the power of = 4. Divide that by the frequency to the power of 2 from your path loss = and you end up with a signal at the receiver that is proportional to the = frequency squared. What does this mean in practice? Well, it means it's = easier to project sharp beams if your carrier frequency is higher. >>=20 >> Now for the D2D phone spectrum that SpaceX are using, we're between 1 = and 2 GHz. The Ku and Ka spectrum band that Starlink is otherwise = licensed for is between 10 and 30 GHz. That's very much back foot = territory for the D2D beams compared to the Ku and Ka ones. >>=20 >> So low bit rate D2D services with few users are a much easier target = to hit than 4G data rates for the rural populus at large. >>=20 >> On 4/06/2024 11:54 pm, Frantisek Borsik via Starlink wrote: >>> The whole article is worth reading, but tl;dr; >>> "The promise of D2D is alluring =E2=80=93 that we can be connected = wherever we are =E2=80=93 no more not-spots and the certainty of always = being able to contact others. But the reality is some way from this. The = only existing D2D service is Apple=E2=80=99s iPhone emergency = communications which offers messaging to the emergency services and = vehicle assistance in 16 countries. This does not appear to be a service = Apple thinks it can charge for at present. >>> Those offerings that have the greatest potential for ubiquity are = within the MSS spectrum. But here bandwidths are too constrained to = deliver full service capabilities. Other MSS operators such as Iridium = have struggled to put together a commercial D2D proposition (although = their core business remains strong). >>> The other approach of using MS spectrum has strong backers in the = form of SpaceX and T-Mobile as well as multiple promising start-ups. But = it is beset with challenges of avoiding interference with existing = terrestrial use, overcoming restrictions in border areas, ensuring = compliance with hundreds of regulators, of which only one has a defined = policy towards D2D at present, doing deals with hundreds of operators = and managing other regulatory hurdles. Only US-based coverage looks = likely any time soon and the true extent of that remains unclear. >>> With limited offers, the consumer interest will be less. Quite how = much less is very unclear, but it is clear that the business case will = be challenging. Most consumers appear to have limited interest in paying = more per month for better coverage. >>> In summary, D2D=E2=80=99s alluring promise of ubiquitous = fully-featured global connectivity is not likely to be realised any time = soon, if ever, but a reduced service level in a few countries may be = sufficient to justify launching suitable satellites." >>> All the best, >>> Frank >>> Frantisek (Frank) Borsik >>> https://www.linkedin.com/in/frantisekborsik >>> Signal, Telegram, WhatsApp: +421919416714 >>> iMessage, mobile: +420775230885 >>> Skype: casioa5302ca >>> frantisek.borsik@gmail.com >>> On Tue, Jun 4, 2024 at 1:43=E2=80=AFPM Alexandre Petrescu via = Starlink wrote: >>>=20 >>> does it say whether it is text only, data only, or everything >>> including voice? >>>=20 >>> Le 04/06/2024 =C3=A0 13:20, Frantisek Borsik via Starlink a = =C3=A9crit : >>>> Some additional reading from William Webb: >>>>=20 >>>> = https://www.linkedin.com/pulse/satellite-direct-device-workable-william-we= bb-sonke/?trackingId=3DSjha4DY8SqONFA9g%2Bb5b%2Bw%3D%3D >>>>=20 >>>> All the best, >>>>=20 >>>> Frank >>>>=20 >>>> Frantisek (Frank) Borsik >>>>=20 >>>> https://www.linkedin.com/in/frantisekborsik >>>>=20 >>>> Signal, Telegram, WhatsApp: +421919416714 >>>>=20 >>>> iMessage, mobile: +420775230885 >>>>=20 >>>> Skype: casioa5302ca >>>>=20 >>>> frantisek.borsik@gmail.com >>>>=20 >>>> On Tue, Jun 4, 2024 at 2:54=E2=80=AFAM David Lang = wrote: >>>>=20 >>>> Eugene Y Chang wrote: >>>>=20 >>>> >> On Jun 3, 2024, at 12:41 PM, David Lang = wrote: >>>> >> >>>> >> Eugene Y Chang wrote: >>>> >> >>>> >>> I expect low data rate because the distance will fall >>>> back to a lower coding rate. >>>> >> >>>> >> I think it's going to be more a matter of very large >>>> cells, so many people sharing the available bandwidth >>>> >> >>>> >>> I observe a difference in my phone=E2=80=99s batter life = between >>>> urban and rural usage. I expect the battery life to be >>>> significantly reduced with Starlink. >>>> >>> And yes=E2=80=A6 if the phone isn=E2=80=99t = communicating then the >>>> battery life isn=E2=80=99t drawn down much=E2=80=A6 >>>> >> >>>> >> In my experience, a phone that's trying to find a tower >>>> uses more power than one that has a tower, but is otherwise = idle >>>> > >>>> > When the phone is searching for a tower, it is = transmitting >>>> at maximum power. >>>> > Then, the phone adjusts the transmit power according to = the >>>> distance to the tower, >>>> > In an urban environment, the distance to the tower is >>>> usually less (i.e. smaller cells due to subscriber density). >>>> > In a rural environment, there is more distance to the >>>> tower, and the phone is transmitting at higher power (i.e., >>>> towers are farther apart for larger cells due to fewer >>>> subscribers per tower, up to the max tower separation.) >>>> > When you are mobile, the power is proportionate to the = mean >>>> distance to the tower during your operations. >>>>=20 >>>> and for direct-to-satellite, it's going to be a max power >>>> situation, similar to >>>> rural. >>>>=20 >>>> But when a phone is not connected, how frequent are it's >>>> searches for towers >>>> (especially if it has multiple bands to check) compared to >>>> the 'keepalive' pings >>>> when it is connected? if it's doing more transmissions for >>>> it's search and >>>> attempts to connect than it does while connected and just >>>> confirming the >>>> connection, that could eat more power. >>>>=20 >>>> David Lang >>>>=20 >>>> _______________________________________________ >>>> Starlink mailing list >>>> Starlink@lists.bufferbloat.net >>>> https://lists.bufferbloat.net/listinfo/starlink >>> _______________________________________________ >>> Starlink mailing list >>> Starlink@lists.bufferbloat.net >>> https://lists.bufferbloat.net/listinfo/starlink >>> _______________________________________________ >>> Starlink mailing list >>> Starlink@lists.bufferbloat.net >>> https://lists.bufferbloat.net/listinfo/starlink >>=20 > _______________________________________________ > Starlink mailing list > Starlink@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/starlink = > _______________________________________________ > Starlink mailing list > Starlink@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/starlink = --Apple-Mail=_4EBD8687-34E6-4261-AC7D-131CBB6C77E3 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8
so it = really is going to be low bandwidth for emergancy use or VERY rural = uses


Or to drive = (unrealistic) consumer demand =E2=80=A6..

Gene
-------------------------------------------= ---
Eugene Chang






On Jun 4, 2024, at 8:10 AM, David Lang via Starlink <starlink@lists.bufferbloat.net> wrote:

And we have statements that the direct to satellite cell = service SpaceX is rolling out will have very large cells, even with the = large antennas on the satellites.

I seem to remember something about cells beitn 70 miles or so = large.

so it really = is going to be low bandwidth for emergancy use or VERY rural = uses

David = Lang

Ulrich = Speidel wrote:

Yep. Getting 17 Mb/s from a single = satellite to a single cellphone is one thing. But serving multiple/many = users is a different story. Because if that's what you want to do, you = only have a few options:

* Share the beam = capacity between them - everyone gets a slice.
* Have more = (and smaller) beams, so the same frequency can be used in
 parallel for multiple users. This requires more and = larger antennas
 on the satellite.
* Up = EIRP to get more power down to Earth. This requires larger
 antennas on the satellite.

As a general rule, when it comes to having sharp beams, both = antenna gain (for a fixed size antenna) and path loss between spacecraft = and ground increase with the square of the carrier frequency. Antenna = gain helps us to get a nice signal at the receiver, path loss works = against us in this sense. We have one antenna at each end - and gains = multiply - so that gives us a term that's proportional to frequency to = the power of 4. Divide that by the frequency to the power of 2 from your = path loss and you end up with a signal at the receiver that is = proportional to the frequency squared. What does this mean in practice? = Well, it means it's easier to project sharp beams if your carrier = frequency is higher.

Now for the D2D phone = spectrum that SpaceX are using, we're between 1 and 2 GHz. The Ku and Ka = spectrum band that Starlink is otherwise licensed for is between 10 and = 30 GHz. That's very much back foot territory for the D2D beams compared = to the Ku and Ka ones.

So low bit rate D2D = services with few users are a much easier target to hit than 4G data = rates for the rural populus at large.

On = 4/06/2024 11:54 pm, Frantisek Borsik via Starlink wrote:
The whole article is = worth reading, but tl;dr;
"The promise of D2D is alluring = =E2=80=93 that we can be connected wherever we are =E2=80=93 no more = not-spots and the certainty of always being able to contact others. But = the reality is some way from this. The only existing D2D service is = Apple=E2=80=99s iPhone emergency communications which offers messaging = to the emergency services and vehicle assistance in 16 countries. This = does not appear to be a service Apple thinks it can charge for at = present.
Those offerings that have the greatest potential = for ubiquity are within the MSS spectrum. But here bandwidths are too = constrained to deliver full service capabilities. Other MSS operators = such as Iridium have struggled to put together a commercial D2D = proposition (although their core business remains strong).
The other approach of using MS spectrum has strong backers in = the form of SpaceX and T-Mobile as well as multiple promising start-ups. = But it is beset with challenges of avoiding interference with existing = terrestrial use, overcoming restrictions in border areas, ensuring = compliance with hundreds of regulators, of which only one has a defined = policy towards D2D at present, doing deals with hundreds of operators = and managing other regulatory hurdles. Only US-based coverage looks = likely any time soon and the true extent of that remains unclear.
With limited offers, the consumer interest will be less. = Quite how much less is very unclear, but it is clear that the business = case will be challenging. Most consumers appear to have limited interest = in paying more per month for better coverage.
In summary, = D2D=E2=80=99s alluring promise of ubiquitous fully-featured global = connectivity is not likely to be realised any time soon, if ever, but a = reduced service level in a few countries may be sufficient to justify = launching suitable satellites."
All the best,
Frank
Frantisek (Frank) Borsik
https://www.linkedin.com/in/frantisekborsik
Signal, Telegram, WhatsApp: +421919416714
iMessage, mobile: +420775230885
Skype: = casioa5302ca
frantisek.borsik@gmail.com
On = Tue, Jun 4, 2024 at 1:43=E2=80=AFPM Alexandre Petrescu via Starlink = <starlink@lists.bufferbloat.net> wrote:

   does it say whether it is text only, data = only, or everything
   including voice?

   Le 04/06/2024 =C3=A0 13:20, = Frantisek Borsik via Starlink a =C3=A9crit :
   Some = additional reading from William Webb:

   https://www.linkedin.com/pulse/satellite-dire= ct-device-workable-william-webb-sonke/?trackingId=3DSjha4DY8SqONFA9g%2Bb5b= %2Bw%3D%3D

   All the = best,

   Frank

   Frantisek (Frank) Borsik

   https://www.linkedin.com/in/frantisekborsik
   Signal, Telegram, = WhatsApp: +421919416714

   iMessage, mobile: +420775230885

   Skype: casioa5302ca

   frantisek.borsik@gmail.com

   On Tue, Jun 4, 2024 at = 2:54=E2=80=AFAM David Lang <david@lang.hm> wrote:

       Eugene Y Chang = wrote:

       >> On Jun 3, = 2024, at 12:41 PM, David Lang <david@lang.hm> wrote:
       >>
       >> Eugene Y = Chang wrote:
       >>
       >>> I = expect low data rate because the distance will fall
       back to a lower = coding rate.
       >>
       >> I think = it's going to be more a matter of very large
       cells, so many = people sharing the available bandwidth
       >>
       >>> I = observe a difference in my phone=E2=80=99s batter life between
       urban and rural = usage. I expect the battery life to be
       significantly = reduced with Starlink.
       >>> And = yes=E2=80=A6 if the phone isn=E2=80=99t communicating then the
       battery life = isn=E2=80=99t drawn down much=E2=80=A6
       >>
       >> In my = experience, a phone that's trying to find a tower
       uses more power = than one that has a tower, but is otherwise idle
       >
       > When the phone = is searching for a tower, it is transmitting
       at maximum = power.
       > = Then, the phone adjusts the transmit power according to the
       distance to the = tower,
       > In = an urban environment, the distance to the tower is
       usually less (i.e. = smaller cells due to subscriber density).
       > In a rural = environment, there is more distance to the
       tower, and the = phone is transmitting at higher power (i.e.,
       towers are farther = apart for larger cells due to fewer
       subscribers per = tower, up to the max tower separation.)
       > When you are = mobile, the power is proportionate to the mean
       distance to the = tower during your operations.

       and for = direct-to-satellite, it's going to be a max power
       situation, similar = to
       rural.

       But = when a phone is not connected, how frequent are it's
       searches for = towers
       (especially= if it has multiple bands to check) compared to
       the 'keepalive' = pings
       when it is = connected? if it's doing more transmissions for
       it's search and
       attempts to connect = than it does while connected and just
       confirming the
       connection, that = could eat more power.

       David Lang

   _____________________________________________= __
   Starlink mailing list
   Starlink@lists.bufferbloat.net
   https://lists.bufferbloat.net/listinfo/starli= nk
   ________________________________= _______________
   Starlink mailing list
   Starlink@lists.bufferbloat.net
   https://lists.bufferbloat.net/listinfo/starli= nk
_______________________________________________
Starlink mailing list
Starlink@lists.bufferbloat.net
https://lists.bufferbloat.net/listinfo/starlink

_______________________________________________
Starlink = mailing list
Starlink@lists.bufferbloat.net
https://lists.bufferbloat.net/listinfo/starlink
_______________________________________________
Starlink = mailing list
Starlink@lists.bufferbloat.net
https://lists.bufferbloat.net/listinfo/starlink

= --Apple-Mail=_4EBD8687-34E6-4261-AC7D-131CBB6C77E3-- --Apple-Mail=_867B2639-0B4D-4F3B-A323-EC8AB4010792 Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEERPTGiBqcibajhTSsv0/8FiYdKmAFAmZfYjkACgkQv0/8FiYd KmD5Dw/+NhufSyhE9JXkj5nWkB8fP21bCHDFKP4uG5oQVB7+kQaGpoAkRUYthFPd I854LCGQSwZdCZyIlaSEMZarvG2ycet5hPVUSddepdg3tVCbQuM0mmgX6hTUQXrX TlbL82ucMxTiO5/4w9b/RXWf9FS9wONYF+9AL+QBZfujmcc/47IBMJ1Zz0b9apK+ 453HXRPU3gqDcJpn68kUjQNCm2q1PnhiEzRzKmMm47fHW7g02uvbQPHnMSdNPTLv 0fJsLfaQjzJVe60Q4WP+FiPfu9AilofI5PQ5m7Hb90F2i+d3LhU1F/XZbRWeSLHt 26AB3SvBPfY6tYyZNuM8E4tvyoEsGJv+fZXlESgYqlAicSxvqWPteW11svq77PBV ylKPqTnM1aV17N7B+lxYrCGlNA/zWaGvsTRXsgyeu74+uhBDRoqftXvM5nNPMLe7 yABeM4j/TBw66iGOuA4Nrpow8SYeCE1MjFl6A1BrU99sqlSCzurTrKesBNeuzViZ y7LFxVsQ69SP2v0x+3vbEt2o1uIONxOq0ZbmENjOXkFYFoZONxYciohha/9YW/4e IfoD6Wh6hFEqI5F3SyXNwoS72NAIGritSQ6lUMuNceykfE9i7UwEHgBjY22/zj5r frx6U9yiyWaTz5+i5QqziUDsemjPfGb7PViR3J2pbtvdhIwdhAA= =YKI+ -----END PGP SIGNATURE----- --Apple-Mail=_867B2639-0B4D-4F3B-A323-EC8AB4010792--