Method of tone allocation for tone hopping sequences

• US 20040213326A1
• Filed: 06/18/2002
• Published: 10/28/2004
• Est. Priority Date: 06/21/2001
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Li, Junyi, Parizhsky, Vladimir
• Granted Patent: US 7,212,564 B2
• Time in Patent Office: Days
• US Class Current: 375/133
• CPC Class Codes: H04B 1/7143 Arrangements for generation of hop patterns
• CPC Class Codes: H04L 5/0039 Frequency-contiguous, i.e. with no allocation of frequencies for one user or terminal between the frequencies allocated to another
• CPC Class Codes: H04L 5/023 Multiplexing of multicarrier modulation signals multicarrier modulation H04L27/2601
• CPC Class Codes: H04W 16/02 Resource partitioning among network components, e.g. reuse partitioning
• CPC Class Codes: H04W 16/12 Fixed resource partitioning
• CPC Class Codes: H04W 72/044 based on the type of the allocated resource
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA

Abstract

Methods and apparatus for allocating tones for communications purposes in adjoining cells of an OFDM system are described. Tones used in each cell are allocated to tone hopping sequences according to a tone to tone hopping sequence allocation function. Different cells use different tone to tone hopping sequence allocation functions to minimize the number of collisions between hopping sequences of neighboring cells. Tone hopping sequence to communications channel allocation functions are used to allocate tone hopping sequences to communications channels. Communications channels are used by wireless terminals, e.g., mobile nodes, to transmit data. Over time, a wireless terminal uses the tones included in the tone hopping sequences corresponding to communications channels it is authorized to use. Accordingly, tones are assigned to communications devices by a multi-function, e.g., two level, mapping operation.

Claims

1. A method of allocating tones in a multi-tone communication system, the system including a plurality of communications devices with overlapping transmission areas, the method comprising:

operating a first communications device to allocate each tone in a first set of P tones to one of a first set of P tone hopping sequences according to a first function, each of the first set of P tones being allocated according to said first function to a different one of the P tone hoping sequences during each of a first set of P sequential tone allocation periods; and

repeating said step of operating a first communications device to allocate each tone in said first set of P tones, such that tones in the first set of P tones are allocated to said first set of P hopping sequences in a pattern that repeats after said first plurality of P tone allocation periods.

2. The method of claim 1, further comprising:

operating a second communications device, having a broadcast area that overlaps at least a portion of a broadcast area of said first communications device, to allocate each tone in a second set of P tones to one of a second set of P tone hopping sequences according to a second function, each of the second set of P tones being allocated according to said second function to a different one of the second P tone hoping sequences during each of said first set of P sequential tone allocation periods, said second function being different from said first function.

3. The method of claim 1, wherein said first communications device is a first base station, the method further comprising:

operating the first base station to allocate at least some hopping sequences to a communications channel according to a third function such that the communications channel includes tones from different hopping functions during different tone allocation periods.

4. The method of claim 3, further comprising:

operating the first base station to assign communications channels, at least one of which is said communications channel, to a mobile node for use in communicating with said first base station; and

receiving information from said mobile node transmitted to said first base station using the tones of a hopping sequence corresponding to a communications channel assigned to said mobile node.

5. The method of claim 2, wherein said first and second functions allocate tones to the first and second sets of P hopping sequences in a manner that allows the tones of any one hopping sequence in the first set of hopping sequences to collide with any one hopping sequence in the second set of P hopping sequences at most twice during any P sequential tone allocation periods.

6. The method of claim 5, wherein when the frequency of said tones in said first set of P tones is synchronized to match the frequency of said tones in said second set of P tones, said tones of said any one hopping sequence in the first set of hopping sequences will collide with the tones of any one hopping sequence in the second set of P hopping sequences at most once during any P sequential tone allocation periods.

7. The method of claim 1, wherein the first function can be expressed as follows:

$f_{\left(\mathrm{fo},t\right)}=\{\begin{array}{cc}\frac{s}{\left(t+f_0\right)<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{mod}<br><br>\text{\hspace{1em}<br><br>}<br><br>P}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{mod}<br><br>\text{\hspace{1em}<br><br>}<br><br>P,& \left(t+f_0\right)<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{mod}<br><br>\text{\hspace{1em}<br><br>}<br><br>P\ne <br><br>0\\ 0,& \left(t+f_0\right)<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{mod}<br><br>\text{\hspace{1em}<br><br>}<br><br>P=0\end{array}$(t+f₀)mod P≠

0 (t+f₀)mod P=0

where f_(fo,t) is the index of a tone allocated to hopping sequence f_o for use in a time period corresponding to integer value t, and where s and P are constant integer values.

8. The method of claim 2, wherein the second function differs from the first function by the use of a different value for s in the first and second communications devices.

9. The method of claim 1, further comprising:

operating the first communications device to assign a plurality of tone hopping sequences to a logical communications channel using a third hopping function.

10. The method of claim 9, wherein said step of operating the first communications device to assign a plurality of tone hopping sequences to a logical communications channel includes:

operating the first communications device to assign different tone hopping sequences to said logical communications channel during each of a plurality of sequential tone allocation time periods.

11. The method of claim 2, wherein said first communications device is a first base station which is part of a first communications cell, the method comprising:

operating a mobile node in said first communications cell to implement said first function to determine which tones to transmit on during at least some of said P sequential tone allocation periods.

12. The method of claim 11, wherein said first base station includes an OFDM receiver;

and

wherein said hopping sequences are OFDM tone hopping sequences.

13. A communications system comprising:

a first tone hopping communications device including;

i. means for allocating each tone, in a first set of P tones, once during each of a first plurality of P sequential tone allocation periods to a different one of a first plurality of P tone hopping sequences used to determine tone allocation for communications with another communications device according to a first function, each of the P tones being allocated according to said first function to a different one of the P tone hoping sequences during each of the plurality of P sequential tone allocation periods; and

ii. means for repeating said step operating a first communications device to allocate each tone in said first set of P tones, such that tones are allocated to hopping sequences in a pattern that repeats after said first plurality of P tone allocation periods.

14. The communications system of claim 13, further comprising:

a second communications device having a broadcast area which overlaps at least a portion of the broadcast range of said first communications device, said second communications device including;

means for allocate each tone, in a second set of P tones, once during each of the first plurality of P sequential tone allocation periods to a different one of a second plurality of P tone hopping sequences according to a second function, each of the P tones being allocated according to said second function to a different one of the second plurality of P tone hoping sequences during each of the plurality of P sequential tone allocation periods, said second function being different from said first function.

15. The communications system of claim 13, wherein said first communications device is a first base station, the first base station further including:

means for allocating at least some hopping sequences to a communications channel according to a third function such that the communications channel comprises tones from different hopping functions during different tone allocation periods.

16. The communication system of claim 15, wherein said first base station further includes:

means for assigning communications channels, at least one of which is said communications channel, to a mobile node for use in communicating with said first base station.

17. The communications system of claim 16, wherein said first base station further includes:

a receiver for receiving information from said mobile node transmitted to said first base station using the tones of a hopping sequence corresponding to a communications channel assigned to said mobile node.

18. The communications system of claim 14, wherein said first and second functions allocate tones to the first and second sets of P hopping sequences in a manner that allows the tones of any one hopping sequence in the first set of hopping sequences to collide with any one hopping sequence in the second set of P hopping sequences at most twice during any P sequential tone allocation periods.

19. The communications system of claim 13, wherein the first function can be expressed as follows:

$f_{\left(\mathrm{fo},t\right)}=\{\begin{array}{cc}\frac{s}{\left(t+f_0\right)<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{mod}<br><br>\text{\hspace{1em}<br><br>}<br><br>P}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{mod}<br><br>\text{\hspace{1em}<br><br>}<br><br>P,& \left(t+f_0\right)<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{mod}<br><br>\text{\hspace{1em}<br><br>}<br><br>P\ne <br><br>0\\ 0,& \left(t+f_0\right)<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{mod}<br><br>\text{\hspace{1em}<br><br>}<br><br>P=0\end{array}$(t+f₀)mod P≠

0 (t+f₀)mod P=0

where f_(fo,t) is the index of a tone allocated to hopping sequence f_o for use in a time period corresponding to integer value t, and where s and P are constant integer values stored by said first base station.

20. The communications system of claim 19,

wherein the second function differs from the first function by the use of a different value for s in the first and second communications devices;

and

wherein the second base station includes memory including the value s used to implement said second function.

21. A method of operating a communications device in a multi-tone communications system, comprising:

determining which tones correspond to a first set of tone hopping sequences using a first function which assigns a different tone to each of P different tone hopping sequences during each of P sequential tone allocation periods;

determining which tone hoping sequences correspond to a communications channel during a particular tone allocation period using a second function which assigns at least some of said tone hopping sequences to said communications channel; and

transmitting data using the tones of the tone hopping sequences determined to correspond to said communication channel.