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gfast map June 2017

Dark blue: Firm commitments from incumbent: BT (10M), Belgacom, Australian NBN, Swisscom,  Austria, Bezeq Israel, Chunghwa Taiwan, Telus Canada, Telekom South Africa, SK Korea, (U.S.) AT&T, Century, Frontier, Windstream

Light blue: Smaller carriers" Germany, Norway, Finland, Japan

Green: Incumbent likely: Belgium, France, Germany, & Poland  Country by country details. 

Telcos could have a massive advantage in upstream speed. Sckipio is confident they will deliver an efficient way to switch bandwidth. I want upstream. Jennie does video and we upload terabytes to Amazon's unlimited cloud. My neighbor probably prefers downstream.

This "dynamic time slot allocation" (DTA) demonstrated by Adtran worked over coax. No vectoring is needed because the shielding minimizes any crosstalk. Calix has previously shown G.fast over coax. The engineers are confident they will soon be able to deliver 750 up, 750 down on coax. Their companies have promised that to AT&T, which acquired coax systems with DirecTV.

Vectoring a DTA system in typical telco multi-line binders is much more challenging.

The calculations to vector at 500+ megabits are demanding. Switching upstream and downstream dynamically adds complexity. A British Telecom engineer suggested DTA wasn't ready and would delay needed standards. Everyone is watching the chipmakers for a breakthrough.

DTA has been understood for at least two decades but not previously extended to DSL. Below is a 1998 patent "Method of time-slot allocation in a TDMA communication system." It has been widely used in GPON and wireless.

Adtran's Paris demo was 106MHz based and demonstrated 750Mbps over 100 Meters of spooled coax. Ronan Kelly assures me the system will deliver the same bandwidth over a longer distance. He writes, "For practicality reasons, we only had a 100 meter spool with us for the event."

They sent me this note. 

Please note that the demo solution had a less than ideal aggregate throughput of  ~750 Mbps. We wanted to demonstrate the effect of DTA/DBA during demo not the overall performance of coax as a medium. We make note of the following demo speed limitations which all affected the overall speed performance compared to our current best estimation of the expected coax performance of future versions of the solution:

  • ·Use of pre-standard DTA implementation within the demo system,
  • ·Attenuation caused from the T-connector from the scope used in demo setup,
  • ·Limited  PON OLT traffic engineering and DBA optimization used as DPU uplink within the demo system

Results of Paris demo were as follows:

Splits in US and DS:

o   Symmetric Case: Mds =18, Mus=17: DS 390Mbps, US 359Mbps

o   DS preferred: Mds =28, Mus=7: DS 610Mbps, US 145Mbps

o   US preferred: Mds = 13, Mus = 22: DS 277Mbps, US 467Mbps

They expect:

The current best estimation of the expected coax DTA customer’s G.fast experience is a Total ETR of 880-900Mbps out to 200 meters or 600 feet RG-6 Coax. Note that on coax distances G.fast rate-reach beyond 200 meters (600 feet) does not matter as much, as the video signal does not reach beyond that distance.

The maximum expected TDD Ratio for DTA is from 30-5 to 5-30.  This would result in the following performance with total ETR of 880-900Mbps:

DS = 900 x (30/35) = 771 Mbps

US = 880 x (30/35) = 754 Mbps

 

From: http://www.google.com/patents/US5748624

Method of time-slot allocation in a TDMA communication system 
US 5748624 A
ABSTRACT
An efficient method of time-slot allocation for a communication in a time division multiple access (TDMA) communication system which allocates one or more time-slots in a TDMA frame is provided. When new call request occurs, availability of idle time-slot for the communication is examined. If there is not enough idle time-slot to be allocated for the new call, it is examined whether there is high transmission speed communication using a plurality of time-slots. When any of the high transmission speed communications exist, time-slots are shared by newly requested communication and the high transmission speed communication using a maximum number of time-slots among the high transmission speed communications. Transmission speed adjustment is performed for such high transmission speed communications sharing a part of time-slot. The probability of occurence of call loss is decreased by this method.
IMAGES(11)
Next page
 
CLAIMS(10)
What is claimed is:
1. A method of time-slot allocation for a communication in a time division multiple access (TDMA) communication system which allocates one time-slot for a low transmission speed communication and a plurality of time-slots for a high transmission communication in a TDMA frame, said method comprising the steps of:
detecting a request for a new communication;
examining whether there exist any high transmission speed communications currently communicating in the TDMA communication system, if the number of idle time-slot required for the new communication are not available;
if there exists at least one high transmission speed communication currently communicating in the TDMA communication system, selecting one of the high transmission speed communications, and instructing a mobile terminal involved in the selected high transmission speed communication to suspend communication due to time-slot reallocation;
releasing at least one time-slot from a plurality of time-slots in the selected high transmission speed communication;
notifying the mobile terminal to resume communication with a reduced number of time-slots without using the at least one time-slot; and
allocating the at least one released time-slot to the new communication requested.
2. The method of time-slot allocation as set forth in claim 1, wherein the examining step determines whether there exist any of high transmission speed communications in the TDMA system by determining whether any current communications in the TDMA system use a plurality of time-slots in one TDMA frame.
3. The method of time-slot allocation as set forth in claim 1, wherein a number of time-slots to be released is one when said new communication requested is a low transmission speed communication.
4. The method of time-slot allocation as set forth in claim 1, wherein the selected high transmission speed communication is operated with the reduced number of time-slots at a same time that the new communication requested is operated with the at least one related time-slot.
5. The method of time-slot allocation as set forth in claim 1, wherein the number of released time-slots from the selected high transmission speed communication is set as close as possible to a number of time-slots to be allocated for said new communication requested when said new communication requested is a high transmission speed communication.
6. A method of time-slot allocation for a communication in a time-division multiple access (TDMA) communication system which allocates one time-slot for a low transmission speed communication and a plurality of time-slots for a high-speed transmission speed communication in a TDMA frame, said method comprising the steps of:
detecting a request for new communication;
examining whether there are a sufficient number of idle time-slots currently available for the new communication;
selecting one of high transmission speed communication currently communicating in the TDMA communication system with a maximum allowable number of time-slots in one TDMA frame, and instructing a mobile terminal involved in the selected high transmission speed communication to suspend communication due to time-slot reallocation;
releasing at least one time-slot from the maximum allowable number of time-slots in the selected high transmission speed communication;
performing transmission speed adjustment for the selected high transmission speed communication, the adjustment depending on the number of time-slots being released,
informing the mobile terminal to resume communication with a reduced number of time-slots for the selected high transmission speed communication, the reduced number of time-slots not including the released time-slots; and
allocating at least one released time-slot from the selected high transmission speed communication to the new communication requested.
7. The method of time-slot allocation as set forth in claim 6, wherein a number of time-slots to be released is one when said new communication requested is a low transmission speed communication.
8. The method of time-slot allocation as set forth in claim 6, wherein the selected high transmission speed communication is operated with the reduced number of time-slots at a same time that the new communication requested is operated with the at least one related time-slot.
9. The method of time-slot allocation as set forth in claim 6, wherein the number of released time-slots from the selected high transmission speed communication is set as close as possible to a number of time-slots to be allocated for said new communication requested when said new communication requested is a high transmission speed communication.
10. A method of time-slot allocation for a communication in a time-division multiple access (TDMA) communication system which allocates one time-slot for a low transmission speed communication and a plurality of time-slots for a high-speed transmission speed communication in a TDMA frame, said method comprising the steps of:
detecting any of idle time-slots becoming available due to completion of communication in the TDMA communication system;
finding a high transmission speed communication performing transmission speed adjustment with an insufficient number of time-slots in a carrier with no more idle time-slot available;
finding a different carrier having sufficient idle time-slots becoming available for use of a plurality of time-slots of said high transmission speed communication being found; and
reallocating complete time-slots of said high transmission speed communication to the different carrier for allowing the high transmission speed communication to use a sufficient number of time-slots.
DESCRIPTION
BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of time-slot allocation in a time division multiple access (TDMA) communication system which allocates one or more time-slots in a TDMA frame for a communication signal to perform the communication, and, more particularly, to a method of efficient time-slot allocation for high transmission speed data communication.

2. Description of the Related Art

In conventional TDMA communication systems, there has been proposed a method in which a plurality of fixed number of time-slots are allocated to a communication signal having a higher transmission speed than the transmission speed of one time-slot in a TDMA frame.

An example of conventional methods of allocating a plurality of fixed number of time-slots in a TDMA frame is described in Japanese Patent Application Laid-Open No. Hei 2-203632.

FIGS. 1(A) and 1(B) show a system construction and a TDMA frame, respectively, for explaining this conventional technique.

This system is constituted by a public telephone network 10, a gateway exchange 20 for switching and connecting the public telephone network 10 and a mobile radio communication system which is adopting a TDMA communication system. The mobile radio communication system is constituted by a radio channel control station 35 connected to the gateway exchange 20, a base station 40 connected to the radio channel control station 35 and a plurality of mobile terminals 60 which can communicate, within a cell 50 where the base station 40 covers, with the base station 40 by radio signals.

The radio channel control station 35 has a function of allocating a plurality of fixed number of time-slots to a communication signal having a higher transmission speed than the transmission speed provided for one time-slot in a TDMA frame.

FIG. 1(B) is a diagram showing an example of the TDMA frame construction of the carrier when a plurality of time-slots are allocated to a communication signal having a higher transmission speed than the transmission speed provided for one time-slot in the TDMA frame. In this case, one time-slot is capable of transferring one channel of low transmission speed communication signal indicated by T1 or T2. In this time-slot provision, 4 time-slots are allocated to high transmission speed communication signal indicated by D1.

For an example, if one time-slot is provided for having a capability of transferring 32 kbps signal, communication signal of 64 kbps is allocated to two time-slots, and communication signal of 128 kbps is allocated to four time-slots.

In the aforementioned conventional time-slot allocating method, the TDMA frame is constructed such that one time-slot corresponds to the lowest transmission speed signal, and with respect to a higher transmission speed signal, various kinds of transmission speed signals are dealt with by allocating a plurality of fixed number of time-slots enough for transferring the data. Therefore, if a ratio of the number of higher transmission speed communication is larger than the lowest transmission speed communication in the TDMA communication system, the probability of requiring a plurality of idle time-slots to be allocated at the same time to a new communication request will be increased. As the result, there is the drawback that the probability of call loss is increased because the call request which needs a plurality of time-slots enough for transferring the data is rejected if sufficient idle time-slots are not available at the time of time-slots allocation.

SUMMARY OF THE INVENTION

The objective of the present invention is to provide an efficient TDMA time-slot allocating method which is capable of flexible time-slots allocation for a high transmission speed communication for reducing the call loss of a newly requested call when a ratio of high transmission speed communication is relatively large in the communication system.

A method of time-slot allocation for a communication in a time division multiple access (TDMA) communication system which allocates one or more time-slots in a TDMA frame, comprises the following steps:

(1) detecting a request for new communication;

(2) examining whether number of idle time-slot required for the new communication detected is available;

(3) examining whether any of high transmission speed communication using a plurality of time-slots exist, if the number of idle time-slot required for the new communication is not available;

(4) releasing at least one time-slot from a plurality of time-slots being used for one of the high transmission speed communications existing; and

(5) allocating the released time-slot to the new communication requested.

According to the present invention, allocation of time-slots for the high transmission speed communication has a flexibility. Although all time-slots required for transmitting the data in the normal speed is preferable, it can be reduced depending on the availability of idle time-slot for a newly requested call. If there is not enough idle time-slot for the new call, a part of time-slots currently being used for the high transmission speed communication is released and used for the new call to avoid rejection of a call request due to non-availability of idle time-slot.

The method of time-slot allocation as set forth above further comprises the following steps in releasing at least one time-slot from a plurality of time-slots being used for one of the high transmission speed communications existing:

(1) examining the high transmission speed communication using a maximum number of time-slots;

(2) releasing at least one time-slot from a plurality of time-slots being used for the high transmission speed communication examined; and

(3) performing transmission speed adjustment depending on the number of time-slots being released.

The high transmission speed communication whose time-slot is partially released is selected from those which are using a maximum number of time-slots, and transmission speed adjustment should be performed because it is no longer being allocated a sufficient number of time-slots to support the current transmission speed.

When releasing time-slot of the high transmission speed communication, the following should also be considered:

(1) releasing at least one time-slot so that a number of time-slots of the high transmission speed communication being examined and a number of time-slots of the new high transmission speed communication become as equal as possible.

There is another aspect of the present invention.

A method of time-slot allocation for a communication in a TDMA communication system comprises the following steps:

(1) detecting any of idle time-slots becoming available due to completion of other communication;

(2) finding a high transmission speed communication using an insufficient number of time-slots; and

(3) allocating time-slots becoming available to the high transmission speed communication that is using the insufficient number of time-slots.

This is time-slot reallocation when idle time-slot becomes available. Those time-slots are to be reallocated to a high transmission speed communication having an insufficient number of time-slots.

The method of time-slot allocation as set forth (time-slot reallocation), further comprises the step of:

(1) changing over a high transmission speed communication from a different carrier, when the idle time-slots becoming available are no longer used in the same carrier but demand exists in a different carrier.

It means that idle time-slots becoming available are allowed to be allocated to a high transmission speed communication currently being allocated in the different carrier as far as this allocation contributes to efficient use of the communication system.

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