Multiple access frequency hopping network with interference anticipation
First Claim
1. A data communication system comprising:
- a plurality of radio devices communicating together in groups defining networks, at least certain member devices of the networks transmitting on the respective said network during time slots and at radio frequencies determined by a frequency hopping sequence;
wherein at least two of said groups having different frequency hopping sequences are sufficiently related that messages transmitted by at least two of the member devices can collide by causing at least one of co-channel and related channel interference between messages of the at least two said groups;
wherein at least one of the devices compares the different radio frequency hopping sequences of the at least two said groups and identifies time slots at which said sequences coincide sufficiently to produce said interference; and
, wherein at least one of said networks alters its behavior during the time slots at which the sequences coincide sufficiently to produce said interference, in a manner that reduces one of an incidence and an effect of collisions during the time slots when the sequences collide.
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Accused Products
Abstract
Spread spectrum packet-switching radio devices are operated in two or more ad-hoc networks or pico-networks that share frequency-hopping channels and time slots that may collide. The piconets can be short range wireless associations of communicating devices, for example according to the Bluetooth, Home RF or similar industry protocols. One device in each piconet is a synchronizing master and others are slaves that follow the master'"'"'s frequency hopping sequence. The sequences of two or more operating piconets (masters) occasionally coincide, which could cause simultaneous transmissions that interfere or collide. The frequency hopping sequences of two or more masters are exchanged using identity codes, permitting the devices to anticipate collision time slots. Priorities are assigned to the simultaneously operating piconets during collision slots, e.g., as a function of their message queue size or latency, or other factors. Lower priority devices may abstain from transmitting during predicted collision slots, and/or a higher priority device may employ enhanced transmission resources during those slots, such as higher error correction levels, or various combinations of abstinence and error correction may be applied. Collisions are avoided or the higher priority piconet is made likely to prevail in a collision. Priorities are repetitively re-determined and re-assigned, to allocate communications resources among all the devices and piconets.
174 Citations
19 Claims
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1. A data communication system comprising:
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a plurality of radio devices communicating together in groups defining networks, at least certain member devices of the networks transmitting on the respective said network during time slots and at radio frequencies determined by a frequency hopping sequence;
wherein at least two of said groups having different frequency hopping sequences are sufficiently related that messages transmitted by at least two of the member devices can collide by causing at least one of co-channel and related channel interference between messages of the at least two said groups;
wherein at least one of the devices compares the different radio frequency hopping sequences of the at least two said groups and identifies time slots at which said sequences coincide sufficiently to produce said interference; and
,wherein at least one of said networks alters its behavior during the time slots at which the sequences coincide sufficiently to produce said interference, in a manner that reduces one of an incidence and an effect of collisions during the time slots when the sequences collide. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 18, 19)
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12. A method of data communication using a plurality of peer devices, comprising the steps of:
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establishing wireless frequency hopping communications between two or more of the devices such that a plurality of the devices associated as members of a first wireless network are synchronized to time slots and operable to step through a predetermined frequency hopping sequence;
establishing wireless frequency hopping communications between two or more of the devices such that a different plurality of the devices are similarly associated as members of a second wireless network operable to step through a different predetermined frequency hopping sequence, wherein the frequency hopping sequences of the first and second wireless networks differ but can coincide in particular time slots;
comparing the frequency hopping sequences of the first and second wireless networks over a prediction interval and identifying time slots in which said frequency hopping sequences coincide;
altering a behavior of at least one of the first and second wireless networks such that one of the first and second wireless networks has improved ability to receive during said time slots in which the frequency hopping sequences coincide.
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Specification